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nixos/doc: convert Chapter 7, 9, 10, 11, 12, 14, 15, 48 to CommonMark
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@ -15,17 +15,17 @@
</partintro>
<xi:include href="config-syntax.xml" />
<xi:include href="package-mgmt.xml" />
<xi:include href="user-mgmt.xml" />
<xi:include href="../from_md/configuration/user-mgmt.chapter.xml" />
<xi:include href="file-systems.xml" />
<xi:include href="x-windows.xml" />
<xi:include href="wayland.xml" />
<xi:include href="gpu-accel.xml" />
<xi:include href="xfce.xml" />
<xi:include href="../from_md/configuration/x-windows.chapter.xml" />
<xi:include href="../from_md/configuration/wayland.chapter.xml" />
<xi:include href="../from_md/configuration/gpu-accel.chapter.xml" />
<xi:include href="../from_md/configuration/xfce.chapter.xml" />
<xi:include href="networking.xml" />
<xi:include href="linux-kernel.xml" />
<xi:include href="subversion.xml" />
<xi:include href="../from_md/configuration/linux-kernel.chapter.xml" />
<xi:include href="../from_md/configuration/subversion.chapter.xml" />
<xi:include href="../generated/modules.xml" xpointer="xpointer(//section[@id='modules']/*)" />
<xi:include href="profiles.xml" />
<xi:include href="kubernetes.xml" />
<xi:include href="../from_md/configuration/kubernetes.chapter.xml" />
<!-- Apache; libvirtd virtualisation -->
</part>

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@ -0,0 +1,204 @@
# GPU acceleration {#sec-gpu-accel}
NixOS provides various APIs that benefit from GPU hardware acceleration,
such as VA-API and VDPAU for video playback; OpenGL and Vulkan for 3D
graphics; and OpenCL for general-purpose computing. This chapter
describes how to set up GPU hardware acceleration (as far as this is not
done automatically) and how to verify that hardware acceleration is
indeed used.
Most of the aforementioned APIs are agnostic with regards to which
display server is used. Consequently, these instructions should apply
both to the X Window System and Wayland compositors.
## OpenCL {#sec-gpu-accel-opencl}
[OpenCL](https://en.wikipedia.org/wiki/OpenCL) is a general compute API.
It is used by various applications such as Blender and Darktable to
accelerate certain operations.
OpenCL applications load drivers through the *Installable Client Driver*
(ICD) mechanism. In this mechanism, an ICD file specifies the path to
the OpenCL driver for a particular GPU family. In NixOS, there are two
ways to make ICD files visible to the ICD loader. The first is through
the `OCL_ICD_VENDORS` environment variable. This variable can contain a
directory which is scanned by the ICL loader for ICD files. For example:
```ShellSession
$ export \
OCL_ICD_VENDORS=`nix-build '<nixpkgs>' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/
```
The second mechanism is to add the OpenCL driver package to
[](#opt-hardware.opengl.extraPackages).
This links the ICD file under `/run/opengl-driver`, where it will be visible
to the ICD loader.
The proper installation of OpenCL drivers can be verified through the
`clinfo` command of the clinfo package. This command will report the
number of hardware devices that is found and give detailed information
for each device:
```ShellSession
$ clinfo | head -n3
Number of platforms 1
Platform Name AMD Accelerated Parallel Processing
Platform Vendor Advanced Micro Devices, Inc.
```
### AMD {#sec-gpu-accel-opencl-amd}
Modern AMD [Graphics Core
Next](https://en.wikipedia.org/wiki/Graphics_Core_Next) (GCN) GPUs are
supported through the rocm-opencl-icd package. Adding this package to
[](#opt-hardware.opengl.extraPackages)
enables OpenCL support:
```nix
hardware.opengl.extraPackages = [
rocm-opencl-icd
];
```
### Intel {#sec-gpu-accel-opencl-intel}
[Intel Gen8 and later
GPUs](https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen8)
are supported by the Intel NEO OpenCL runtime that is provided by the
intel-compute-runtime package. For Gen7 GPUs, the deprecated Beignet
runtime can be used, which is provided by the beignet package. The
proprietary Intel OpenCL runtime, in the intel-ocl package, is an
alternative for Gen7 GPUs.
The intel-compute-runtime, beignet, or intel-ocl package can be added to
[](#opt-hardware.opengl.extraPackages)
to enable OpenCL support. For example, for Gen8 and later GPUs, the following
configuration can be used:
```nix
hardware.opengl.extraPackages = [
intel-compute-runtime
];
```
## Vulkan {#sec-gpu-accel-vulkan}
[Vulkan](https://en.wikipedia.org/wiki/Vulkan_(API)) is a graphics and
compute API for GPUs. It is used directly by games or indirectly though
compatibility layers like
[DXVK](https://github.com/doitsujin/dxvk/wiki).
By default, if [](#opt-hardware.opengl.driSupport)
is enabled, mesa is installed and provides Vulkan for supported hardware.
Similar to OpenCL, Vulkan drivers are loaded through the *Installable
Client Driver* (ICD) mechanism. ICD files for Vulkan are JSON files that
specify the path to the driver library and the supported Vulkan version.
All successfully loaded drivers are exposed to the application as
different GPUs. In NixOS, there are two ways to make ICD files visible
to Vulkan applications: an environment variable and a module option.
The first option is through the `VK_ICD_FILENAMES` environment variable.
This variable can contain multiple JSON files, separated by `:`. For
example:
```ShellSession
$ export \
VK_ICD_FILENAMES=`nix-build '<nixpkgs>' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json
```
The second mechanism is to add the Vulkan driver package to
[](#opt-hardware.opengl.extraPackages).
This links the ICD file under `/run/opengl-driver`, where it will be
visible to the ICD loader.
The proper installation of Vulkan drivers can be verified through the
`vulkaninfo` command of the vulkan-tools package. This command will
report the hardware devices and drivers found, in this example output
amdvlk and radv:
```ShellSession
$ vulkaninfo | grep GPU
GPU id : 0 (Unknown AMD GPU)
GPU id : 1 (AMD RADV NAVI10 (LLVM 9.0.1))
...
GPU0:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
deviceName = Unknown AMD GPU
GPU1:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
```
A simple graphical application that uses Vulkan is `vkcube` from the
vulkan-tools package.
### AMD {#sec-gpu-accel-vulkan-amd}
Modern AMD [Graphics Core
Next](https://en.wikipedia.org/wiki/Graphics_Core_Next) (GCN) GPUs are
supported through either radv, which is part of mesa, or the amdvlk
package. Adding the amdvlk package to
[](#opt-hardware.opengl.extraPackages)
makes amdvlk the default driver and hides radv and lavapipe from the device list.
A specific driver can be forced as follows:
```nix
hardware.opengl.extraPackages = [
pkgs.amdvlk
];
# To enable Vulkan support for 32-bit applications, also add:
hardware.opengl.extraPackages32 = [
pkgs.driversi686Linux.amdvlk
];
# Force radv
environment.variables.AMD_VULKAN_ICD = "RADV";
# Or
environment.variables.VK_ICD_FILENAMES =
"/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json";
```
## Common issues {#sec-gpu-accel-common-issues}
### User permissions {#sec-gpu-accel-common-issues-permissions}
Except where noted explicitly, it should not be necessary to adjust user
permissions to use these acceleration APIs. In the default
configuration, GPU devices have world-read/write permissions
(`/dev/dri/renderD*`) or are tagged as `uaccess` (`/dev/dri/card*`). The
access control lists of devices with the `uaccess` tag will be updated
automatically when a user logs in through `systemd-logind`. For example,
if the user *jane* is logged in, the access control list should look as
follows:
```ShellSession
$ getfacl /dev/dri/card0
# file: dev/dri/card0
# owner: root
# group: video
user::rw-
user:jane:rw-
group::rw-
mask::rw-
other::---
```
If you disabled (this functionality of) `systemd-logind`, you may need
to add the user to the `video` group and log in again.
### Mixing different versions of nixpkgs {#sec-gpu-accel-common-issues-mixing-nixpkgs}
The *Installable Client Driver* (ICD) mechanism used by OpenCL and
Vulkan loads runtimes into its address space using `dlopen`. Mixing an
ICD loader mechanism and runtimes from different version of nixpkgs may
not work. For example, if the ICD loader uses an older version of glibc
than the runtime, the runtime may not be loadable due to missing
symbols. Unfortunately, the loader will generally be quiet about such
issues.
If you suspect that you are running into library version mismatches
between an ICL loader and a runtime, you could run an application with
the `LD_DEBUG` variable set to get more diagnostic information. For
example, OpenCL can be tested with `LD_DEBUG=files clinfo`, which should
report missing symbols.

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@ -1,262 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-gpu-accel">
<title>GPU acceleration</title>
<para>
NixOS provides various APIs that benefit from GPU hardware
acceleration, such as VA-API and VDPAU for video playback; OpenGL and
Vulkan for 3D graphics; and OpenCL for general-purpose computing.
This chapter describes how to set up GPU hardware acceleration (as far
as this is not done automatically) and how to verify that hardware
acceleration is indeed used.
</para>
<para>
Most of the aforementioned APIs are agnostic with regards to which
display server is used. Consequently, these instructions should apply
both to the X Window System and Wayland compositors.
</para>
<section xml:id="sec-gpu-accel-opencl">
<title>OpenCL</title>
<para>
<link xlink:href="https://en.wikipedia.org/wiki/OpenCL">OpenCL</link> is a
general compute API. It is used by various applications such as
Blender and Darktable to accelerate certain operations.
</para>
<para>
OpenCL applications load drivers through the <emphasis>Installable Client
Driver</emphasis> (ICD) mechanism. In this mechanism, an ICD file
specifies the path to the OpenCL driver for a particular GPU family.
In NixOS, there are two ways to make ICD files visible to the ICD
loader. The first is through the <varname>OCL_ICD_VENDORS</varname>
environment variable. This variable can contain a directory which
is scanned by the ICL loader for ICD files. For example:
<screen><prompt>$</prompt> export \
OCL_ICD_VENDORS=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/</screen>
</para>
<para>
The second mechanism is to add the OpenCL driver package to
<xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
ICD file under <filename>/run/opengl-driver</filename>, where it will
be visible to the ICD loader.
</para>
<para>
The proper installation of OpenCL drivers can be verified through
the <command>clinfo</command> command of the <package>clinfo</package>
package. This command will report the number of hardware devices
that is found and give detailed information for each device:
</para>
<screen><prompt>$</prompt> clinfo | head -n3
Number of platforms 1
Platform Name AMD Accelerated Parallel Processing
Platform Vendor Advanced Micro Devices, Inc.</screen>
<section xml:id="sec-gpu-accel-opencl-amd">
<title>AMD</title>
<para>
Modern AMD <link
xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
Core Next</link> (GCN) GPUs are supported through the
<package>rocm-opencl-icd</package> package. Adding this package to
<xref linkend="opt-hardware.opengl.extraPackages"/> enables OpenCL
support:
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
rocm-opencl-icd
];</programlisting>
</para>
</section>
<section xml:id="sec-gpu-accel-opencl-intel">
<title>Intel</title>
<para>
<link
xlink:href="https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen8">Intel
Gen8 and later GPUs</link> are supported by the Intel NEO OpenCL
runtime that is provided by the
<package>intel-compute-runtime</package> package. For Gen7 GPUs,
the deprecated Beignet runtime can be used, which is provided
by the <package>beignet</package> package. The proprietary Intel
OpenCL runtime, in the <package>intel-ocl</package> package, is
an alternative for Gen7 GPUs.
</para>
<para>
The <package>intel-compute-runtime</package>, <package>beignet</package>,
or <package>intel-ocl</package> package can be added to
<xref linkend="opt-hardware.opengl.extraPackages"/> to enable OpenCL
support. For example, for Gen8 and later GPUs, the following
configuration can be used:
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
intel-compute-runtime
];</programlisting>
</para>
</section>
</section>
<section xml:id="sec-gpu-accel-vulkan">
<title>Vulkan</title>
<para>
<link xlink:href="https://en.wikipedia.org/wiki/Vulkan_(API)">Vulkan</link> is a
graphics and compute API for GPUs. It is used directly by games or indirectly though
compatibility layers like <link xlink:href="https://github.com/doitsujin/dxvk/wiki">DXVK</link>.
</para>
<para>
By default, if <xref linkend="opt-hardware.opengl.driSupport"/> is enabled,
<package>mesa</package> is installed and provides Vulkan for supported hardware.
</para>
<para>
Similar to OpenCL, Vulkan drivers are loaded through the <emphasis>Installable Client
Driver</emphasis> (ICD) mechanism. ICD files for Vulkan are JSON files that specify
the path to the driver library and the supported Vulkan version. All successfully
loaded drivers are exposed to the application as different GPUs.
In NixOS, there are two ways to make ICD files visible to Vulkan applications: an
environment variable and a module option.
</para>
<para>
The first option is through the <varname>VK_ICD_FILENAMES</varname>
environment variable. This variable can contain multiple JSON files, separated by
<literal>:</literal>. For example:
<screen><prompt>$</prompt> export \
VK_ICD_FILENAMES=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json</screen>
</para>
<para>
The second mechanism is to add the Vulkan driver package to
<xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
ICD file under <filename>/run/opengl-driver</filename>, where it will
be visible to the ICD loader.
</para>
<para>
The proper installation of Vulkan drivers can be verified through
the <command>vulkaninfo</command> command of the <package>vulkan-tools</package>
package. This command will report the hardware devices and drivers found,
in this example output amdvlk and radv:
</para>
<screen><prompt>$</prompt> vulkaninfo | grep GPU
GPU id : 0 (Unknown AMD GPU)
GPU id : 1 (AMD RADV NAVI10 (LLVM 9.0.1))
...
GPU0:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
deviceName = Unknown AMD GPU
GPU1:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU</screen>
<para>
A simple graphical application that uses Vulkan is <command>vkcube</command>
from the <package>vulkan-tools</package> package.
</para>
<section xml:id="sec-gpu-accel-vulkan-amd">
<title>AMD</title>
<para>
Modern AMD <link
xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
Core Next</link> (GCN) GPUs are supported through either radv, which is
part of <package>mesa</package>, or the <package>amdvlk</package> package.
Adding the <package>amdvlk</package> package to
<xref linkend="opt-hardware.opengl.extraPackages"/> makes amdvlk the
default driver and hides radv and lavapipe from the device list. A
specific driver can be forced as follows:
<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
pkgs.<package>amdvlk</package>
];
# To enable Vulkan support for 32-bit applications, also add:
<xref linkend="opt-hardware.opengl.extraPackages32"/> = [
pkgs.driversi686Linux.<package>amdvlk</package>
];
# Force radv
<xref linkend="opt-environment.variables"/>.AMD_VULKAN_ICD = "RADV";
# Or
<xref linkend="opt-environment.variables"/>.VK_ICD_FILENAMES =
"/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json";
</programlisting>
</para>
</section>
</section>
<section xml:id="sec-gpu-accel-common-issues">
<title>Common issues</title>
<section xml:id="sec-gpu-accel-common-issues-permissions">
<title>User permissions</title>
<para>
Except where noted explicitly, it should not be necessary to
adjust user permissions to use these acceleration APIs. In the default
configuration, GPU devices have world-read/write permissions
(<filename>/dev/dri/renderD*</filename>) or are tagged as
<code>uaccess</code> (<filename>/dev/dri/card*</filename>). The
access control lists of devices with the <varname>uaccess</varname>
tag will be updated automatically when a user logs in through
<command>systemd-logind</command>. For example, if the user
<emphasis>jane</emphasis> is logged in, the access control list
should look as follows:
<screen><prompt>$</prompt> getfacl /dev/dri/card0
# file: dev/dri/card0
# owner: root
# group: video
user::rw-
user:jane:rw-
group::rw-
mask::rw-
other::---</screen>
If you disabled (this functionality of) <command>systemd-logind</command>,
you may need to add the user to the <code>video</code> group and
log in again.
</para>
</section>
<section xml:id="sec-gpu-accel-common-issues-mixing-nixpkgs">
<title>Mixing different versions of nixpkgs</title>
<para>
The <emphasis>Installable Client Driver</emphasis> (ICD)
mechanism used by OpenCL and Vulkan loads runtimes into its address
space using <code>dlopen</code>. Mixing an ICD loader mechanism and
runtimes from different version of nixpkgs may not work. For example,
if the ICD loader uses an older version of <package>glibc</package>
than the runtime, the runtime may not be loadable due to
missing symbols. Unfortunately, the loader will generally be quiet
about such issues.
</para>
<para>
If you suspect that you are running into library version mismatches
between an ICL loader and a runtime, you could run an application with
the <code>LD_DEBUG</code> variable set to get more diagnostic
information. For example, OpenCL can be tested with
<code>LD_DEBUG=files clinfo</code>, which should report missing
symbols.
</para>
</section>
</section>
</chapter>

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# Kubernetes {#sec-kubernetes}
The NixOS Kubernetes module is a collective term for a handful of
individual submodules implementing the Kubernetes cluster components.
There are generally two ways of enabling Kubernetes on NixOS. One way is
to enable and configure cluster components appropriately by hand:
```nix
services.kubernetes = {
apiserver.enable = true;
controllerManager.enable = true;
scheduler.enable = true;
addonManager.enable = true;
proxy.enable = true;
flannel.enable = true;
};
```
Another way is to assign cluster roles (\"master\" and/or \"node\") to
the host. This enables apiserver, controllerManager, scheduler,
addonManager, kube-proxy and etcd:
```nix
services.kubernetes.roles = [ "master" ];
```
While this will enable the kubelet and kube-proxy only:
```nix
services.kubernetes.roles = [ "node" ];
```
Assigning both the master and node roles is usable if you want a single
node Kubernetes cluster for dev or testing purposes:
```nix
services.kubernetes.roles = [ "master" "node" ];
```
Note: Assigning either role will also default both
[](#opt-services.kubernetes.flannel.enable)
and [](#opt-services.kubernetes.easyCerts)
to true. This sets up flannel as CNI and activates automatic PKI bootstrapping.
As of kubernetes 1.10.X it has been deprecated to open non-tls-enabled
ports on kubernetes components. Thus, from NixOS 19.03 all plain HTTP
ports have been disabled by default. While opening insecure ports is
still possible, it is recommended not to bind these to other interfaces
than loopback. To re-enable the insecure port on the apiserver, see options:
[](#opt-services.kubernetes.apiserver.insecurePort) and
[](#opt-services.kubernetes.apiserver.insecureBindAddress)
::: {.note}
As of NixOS 19.03, it is mandatory to configure:
[](#opt-services.kubernetes.masterAddress).
The masterAddress must be resolveable and routeable by all cluster nodes.
In single node clusters, this can be set to `localhost`.
:::
Role-based access control (RBAC) authorization mode is enabled by
default. This means that anonymous requests to the apiserver secure port
will expectedly cause a permission denied error. All cluster components
must therefore be configured with x509 certificates for two-way tls
communication. The x509 certificate subject section determines the roles
and permissions granted by the apiserver to perform clusterwide or
namespaced operations. See also: [ Using RBAC
Authorization](https://kubernetes.io/docs/reference/access-authn-authz/rbac/).
The NixOS kubernetes module provides an option for automatic certificate
bootstrapping and configuration,
[](#opt-services.kubernetes.easyCerts).
The PKI bootstrapping process involves setting up a certificate authority (CA)
daemon (cfssl) on the kubernetes master node. cfssl generates a CA-cert
for the cluster, and uses the CA-cert for signing subordinate certs issued
to each of the cluster components. Subsequently, the certmgr daemon monitors
active certificates and renews them when needed. For single node Kubernetes
clusters, setting [](#opt-services.kubernetes.easyCerts)
= true is sufficient and no further action is required. For joining extra node
machines to an existing cluster on the other hand, establishing initial
trust is mandatory.
To add new nodes to the cluster: On any (non-master) cluster node where
[](#opt-services.kubernetes.easyCerts)
is enabled, the helper script `nixos-kubernetes-node-join` is available on PATH.
Given a token on stdin, it will copy the token to the kubernetes secrets directory
and restart the certmgr service. As requested certificates are issued, the
script will restart kubernetes cluster components as needed for them to
pick up new keypairs.
::: {.note}
Multi-master (HA) clusters are not supported by the easyCerts module.
:::
In order to interact with an RBAC-enabled cluster as an administrator,
one needs to have cluster-admin privileges. By default, when easyCerts
is enabled, a cluster-admin kubeconfig file is generated and linked into
`/etc/kubernetes/cluster-admin.kubeconfig` as determined by
[](#opt-services.kubernetes.pki.etcClusterAdminKubeconfig).
`export KUBECONFIG=/etc/kubernetes/cluster-admin.kubeconfig` will make
kubectl use this kubeconfig to access and authenticate the cluster. The
cluster-admin kubeconfig references an auto-generated keypair owned by
root. Thus, only root on the kubernetes master may obtain cluster-admin
rights by means of this file.

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@ -1,112 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-kubernetes">
<title>Kubernetes</title>
<para>
The NixOS Kubernetes module is a collective term for a handful of individual
submodules implementing the Kubernetes cluster components.
</para>
<para>
There are generally two ways of enabling Kubernetes on NixOS. One way is to
enable and configure cluster components appropriately by hand:
<programlisting>
services.kubernetes = {
apiserver.enable = true;
controllerManager.enable = true;
scheduler.enable = true;
addonManager.enable = true;
proxy.enable = true;
flannel.enable = true;
};
</programlisting>
Another way is to assign cluster roles ("master" and/or "node") to the host.
This enables apiserver, controllerManager, scheduler, addonManager,
kube-proxy and etcd:
<programlisting>
<xref linkend="opt-services.kubernetes.roles"/> = [ "master" ];
</programlisting>
While this will enable the kubelet and kube-proxy only:
<programlisting>
<xref linkend="opt-services.kubernetes.roles"/> = [ "node" ];
</programlisting>
Assigning both the master and node roles is usable if you want a single node
Kubernetes cluster for dev or testing purposes:
<programlisting>
<xref linkend="opt-services.kubernetes.roles"/> = [ "master" "node" ];
</programlisting>
Note: Assigning either role will also default both
<xref linkend="opt-services.kubernetes.flannel.enable"/> and
<xref linkend="opt-services.kubernetes.easyCerts"/> to true. This sets up
flannel as CNI and activates automatic PKI bootstrapping.
</para>
<para>
As of kubernetes 1.10.X it has been deprecated to open non-tls-enabled ports
on kubernetes components. Thus, from NixOS 19.03 all plain HTTP ports have
been disabled by default. While opening insecure ports is still possible, it
is recommended not to bind these to other interfaces than loopback. To
re-enable the insecure port on the apiserver, see options:
<xref linkend="opt-services.kubernetes.apiserver.insecurePort"/> and
<xref linkend="opt-services.kubernetes.apiserver.insecureBindAddress"/>
</para>
<note>
<para>
As of NixOS 19.03, it is mandatory to configure:
<xref linkend="opt-services.kubernetes.masterAddress"/>. The masterAddress
must be resolveable and routeable by all cluster nodes. In single node
clusters, this can be set to <literal>localhost</literal>.
</para>
</note>
<para>
Role-based access control (RBAC) authorization mode is enabled by default.
This means that anonymous requests to the apiserver secure port will
expectedly cause a permission denied error. All cluster components must
therefore be configured with x509 certificates for two-way tls communication.
The x509 certificate subject section determines the roles and permissions
granted by the apiserver to perform clusterwide or namespaced operations. See
also:
<link
xlink:href="https://kubernetes.io/docs/reference/access-authn-authz/rbac/">
Using RBAC Authorization</link>.
</para>
<para>
The NixOS kubernetes module provides an option for automatic certificate
bootstrapping and configuration,
<xref linkend="opt-services.kubernetes.easyCerts"/>. The PKI bootstrapping
process involves setting up a certificate authority (CA) daemon (cfssl) on
the kubernetes master node. cfssl generates a CA-cert for the cluster, and
uses the CA-cert for signing subordinate certs issued to each of the cluster
components. Subsequently, the certmgr daemon monitors active certificates and
renews them when needed. For single node Kubernetes clusters, setting
<xref linkend="opt-services.kubernetes.easyCerts"/> = true is sufficient and
no further action is required. For joining extra node machines to an existing
cluster on the other hand, establishing initial trust is mandatory.
</para>
<para>
To add new nodes to the cluster: On any (non-master) cluster node where
<xref linkend="opt-services.kubernetes.easyCerts"/> is enabled, the helper
script <literal>nixos-kubernetes-node-join</literal> is available on PATH.
Given a token on stdin, it will copy the token to the kubernetes secrets
directory and restart the certmgr service. As requested certificates are
issued, the script will restart kubernetes cluster components as needed for
them to pick up new keypairs.
</para>
<note>
<para>
Multi-master (HA) clusters are not supported by the easyCerts module.
</para>
</note>
<para>
In order to interact with an RBAC-enabled cluster as an administrator, one
needs to have cluster-admin privileges. By default, when easyCerts is
enabled, a cluster-admin kubeconfig file is generated and linked into
<literal>/etc/kubernetes/cluster-admin.kubeconfig</literal> as determined by
<xref linkend="opt-services.kubernetes.pki.etcClusterAdminKubeconfig"/>.
<literal>export KUBECONFIG=/etc/kubernetes/cluster-admin.kubeconfig</literal>
will make kubectl use this kubeconfig to access and authenticate the cluster.
The cluster-admin kubeconfig references an auto-generated keypair owned by
root. Thus, only root on the kubernetes master may obtain cluster-admin
rights by means of this file.
</para>
</chapter>

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@ -0,0 +1,135 @@
# Linux Kernel {#sec-kernel-config}
You can override the Linux kernel and associated packages using the
option `boot.kernelPackages`. For instance, this selects the Linux 3.10
kernel:
```nix
boot.kernelPackages = pkgs.linuxPackages_3_10;
```
Note that this not only replaces the kernel, but also packages that are
specific to the kernel version, such as the NVIDIA video drivers. This
ensures that driver packages are consistent with the kernel.
The default Linux kernel configuration should be fine for most users.
You can see the configuration of your current kernel with the following
command:
```ShellSession
zcat /proc/config.gz
```
If you want to change the kernel configuration, you can use the
`packageOverrides` feature (see [](#sec-customising-packages)). For
instance, to enable support for the kernel debugger KGDB:
```nix
nixpkgs.config.packageOverrides = pkgs:
{ linux_3_4 = pkgs.linux_3_4.override {
extraConfig =
''
KGDB y
'';
};
};
```
`extraConfig` takes a list of Linux kernel configuration options, one
per line. The name of the option should not include the prefix
`CONFIG_`. The option value is typically `y`, `n` or `m` (to build
something as a kernel module).
Kernel modules for hardware devices are generally loaded automatically
by `udev`. You can force a module to be loaded via
[](#opt-boot.kernelModules), e.g.
```nix
boot.kernelModules = [ "fuse" "kvm-intel" "coretemp" ];
```
If the module is required early during the boot (e.g. to mount the root
file system), you can use [](#opt-boot.initrd.kernelModules):
```nix
boot.initrd.kernelModules = [ "cifs" ];
```
This causes the specified modules and their dependencies to be added to
the initial ramdisk.
Kernel runtime parameters can be set through
[](#opt-boot.kernel.sysctl), e.g.
```nix
boot.kernel.sysctl."net.ipv4.tcp_keepalive_time" = 120;
```
sets the kernel's TCP keepalive time to 120 seconds. To see the
available parameters, run `sysctl -a`.
## Customize your kernel {#sec-linux-config-customizing}
The first step before compiling the kernel is to generate an appropriate
`.config` configuration. Either you pass your own config via the
`configfile` setting of `linuxManualConfig`:
```nix
custom-kernel = super.linuxManualConfig {
inherit (super) stdenv hostPlatform;
inherit (linux_4_9) src;
version = "${linux_4_9.version}-custom";
configfile = /home/me/my_kernel_config;
allowImportFromDerivation = true;
};
```
You can edit the config with this snippet (by default `make
menuconfig` won\'t work out of the box on nixos):
```ShellSession
nix-shell -E 'with import <nixpkgs> {}; kernelToOverride.overrideAttrs (o: {nativeBuildInputs=o.nativeBuildInputs ++ [ pkg-config ncurses ];})'
```
or you can let nixpkgs generate the configuration. Nixpkgs generates it
via answering the interactive kernel utility `make config`. The answers
depend on parameters passed to
`pkgs/os-specific/linux/kernel/generic.nix` (which you can influence by
overriding `extraConfig, autoModules,
modDirVersion, preferBuiltin, extraConfig`).
```nix
mptcp93.override ({
name="mptcp-local";
ignoreConfigErrors = true;
autoModules = false;
kernelPreferBuiltin = true;
enableParallelBuilding = true;
extraConfig = ''
DEBUG_KERNEL y
FRAME_POINTER y
KGDB y
KGDB_SERIAL_CONSOLE y
DEBUG_INFO y
'';
});
```
## Developing kernel modules {#sec-linux-config-developing-modules}
When developing kernel modules it\'s often convenient to run
edit-compile-run loop as quickly as possible. See below snippet as an
example of developing `mellanox` drivers.
```ShellSession
$ nix-build '<nixpkgs>' -A linuxPackages.kernel.dev
$ nix-shell '<nixpkgs>' -A linuxPackages.kernel
$ unpackPhase
$ cd linux-*
$ make -C $dev/lib/modules/*/build M=$(pwd)/drivers/net/ethernet/mellanox modules
# insmod ./drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko
```

View File

@ -1,138 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-kernel-config">
<title>Linux Kernel</title>
<para>
You can override the Linux kernel and associated packages using the option
<option>boot.kernelPackages</option>. For instance, this selects the Linux
3.10 kernel:
<programlisting>
<xref linkend="opt-boot.kernelPackages"/> = pkgs.linuxPackages_3_10;
</programlisting>
Note that this not only replaces the kernel, but also packages that are
specific to the kernel version, such as the NVIDIA video drivers. This
ensures that driver packages are consistent with the kernel.
</para>
<para>
The default Linux kernel configuration should be fine for most users. You can
see the configuration of your current kernel with the following command:
<programlisting>
zcat /proc/config.gz
</programlisting>
If you want to change the kernel configuration, you can use the
<option>packageOverrides</option> feature (see
<xref
linkend="sec-customising-packages" />). For instance, to enable support
for the kernel debugger KGDB:
<programlisting>
nixpkgs.config.packageOverrides = pkgs:
{ linux_3_4 = pkgs.linux_3_4.override {
extraConfig =
''
KGDB y
'';
};
};
</programlisting>
<varname>extraConfig</varname> takes a list of Linux kernel configuration
options, one per line. The name of the option should not include the prefix
<literal>CONFIG_</literal>. The option value is typically
<literal>y</literal>, <literal>n</literal> or <literal>m</literal> (to build
something as a kernel module).
</para>
<para>
Kernel modules for hardware devices are generally loaded automatically by
<command>udev</command>. You can force a module to be loaded via
<xref linkend="opt-boot.kernelModules"/>, e.g.
<programlisting>
<xref linkend="opt-boot.kernelModules"/> = [ "fuse" "kvm-intel" "coretemp" ];
</programlisting>
If the module is required early during the boot (e.g. to mount the root file
system), you can use <xref linkend="opt-boot.initrd.kernelModules"/>:
<programlisting>
<xref linkend="opt-boot.initrd.kernelModules"/> = [ "cifs" ];
</programlisting>
This causes the specified modules and their dependencies to be added to the
initial ramdisk.
</para>
<para>
Kernel runtime parameters can be set through
<xref linkend="opt-boot.kernel.sysctl"/>, e.g.
<programlisting>
<xref linkend="opt-boot.kernel.sysctl"/>."net.ipv4.tcp_keepalive_time" = 120;
</programlisting>
sets the kernels TCP keepalive time to 120 seconds. To see the available
parameters, run <command>sysctl -a</command>.
</para>
<section xml:id="sec-linux-config-customizing">
<title>Customize your kernel</title>
<para>
The first step before compiling the kernel is to generate an appropriate
<literal>.config</literal> configuration. Either you pass your own config
via the <literal>configfile</literal> setting of
<literal>linuxManualConfig</literal>:
<screen><![CDATA[
custom-kernel = super.linuxManualConfig {
inherit (super) stdenv hostPlatform;
inherit (linux_4_9) src;
version = "${linux_4_9.version}-custom";
configfile = /home/me/my_kernel_config;
allowImportFromDerivation = true;
};
]]></screen>
You can edit the config with this snippet (by default <command>make
menuconfig</command> won't work out of the box on nixos):
<screen><![CDATA[
nix-shell -E 'with import <nixpkgs> {}; kernelToOverride.overrideAttrs (o: {nativeBuildInputs=o.nativeBuildInputs ++ [ pkg-config ncurses ];})'
]]></screen>
or you can let nixpkgs generate the configuration. Nixpkgs generates it via
answering the interactive kernel utility <command>make config</command>. The
answers depend on parameters passed to
<filename>pkgs/os-specific/linux/kernel/generic.nix</filename> (which you
can influence by overriding <literal>extraConfig, autoModules,
modDirVersion, preferBuiltin, extraConfig</literal>).
<screen><![CDATA[
mptcp93.override ({
name="mptcp-local";
ignoreConfigErrors = true;
autoModules = false;
kernelPreferBuiltin = true;
enableParallelBuilding = true;
extraConfig = ''
DEBUG_KERNEL y
FRAME_POINTER y
KGDB y
KGDB_SERIAL_CONSOLE y
DEBUG_INFO y
'';
});
]]></screen>
</para>
</section>
<section xml:id="sec-linux-config-developing-modules">
<title>Developing kernel modules</title>
<para>
When developing kernel modules it's often convenient to run edit-compile-run
loop as quickly as possible. See below snippet as an example of developing
<literal>mellanox</literal> drivers.
</para>
<screen>
<prompt>$ </prompt>nix-build '&lt;nixpkgs>' -A linuxPackages.kernel.dev
<prompt>$ </prompt>nix-shell '&lt;nixpkgs>' -A linuxPackages.kernel
<prompt>$ </prompt>unpackPhase
<prompt>$ </prompt>cd linux-*
<prompt>$ </prompt>make -C $dev/lib/modules/*/build M=$(pwd)/drivers/net/ethernet/mellanox modules
<prompt># </prompt>insmod ./drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko
</screen>
</section>
</chapter>

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@ -34,7 +34,7 @@ SHA256:yjxl3UbTn31fLWeyLYTAKYJPRmzknjQZoyG8gSNEoIE my-user@workstation
To keep the key safe, change the ownership to `root:root` and make sure the permissions are `600`:
OpenSSH normally refuses to use the key if it's not well-protected.
The file system can be configured in NixOS via the usual [fileSystems](options.html#opt-fileSystems) option.
The file system can be configured in NixOS via the usual [fileSystems](#opt-fileSystems) option.
Here's a typical setup:
```nix
{

View File

@ -0,0 +1,102 @@
# Subversion {#module-services-subversion}
[Subversion](https://subversion.apache.org/) is a centralized
version-control system. It can use a [variety of
protocols](http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.choosing)
for communication between client and server.
## Subversion inside Apache HTTP {#module-services-subversion-apache-httpd}
This section focuses on configuring a web-based server on top of the
Apache HTTP server, which uses
[WebDAV](http://www.webdav.org/)/[DeltaV](http://www.webdav.org/deltav/WWW10/deltav-intro.htm)
for communication.
For more information on the general setup, please refer to the [the
appropriate section of the Subversion
book](http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.httpd).
To configure, include in `/etc/nixos/configuration.nix` code to activate
Apache HTTP, setting [](#opt-services.httpd.adminAddr)
appropriately:
```nix
services.httpd.enable = true;
services.httpd.adminAddr = ...;
networking.firewall.allowedTCPPorts = [ 80 443 ];
```
For a simple Subversion server with basic authentication, configure the
Subversion module for Apache as follows, setting `hostName` and
`documentRoot` appropriately, and `SVNParentPath` to the parent
directory of the repositories, `AuthzSVNAccessFile` to the location of
the `.authz` file describing access permission, and `AuthUserFile` to
the password file.
```nix
services.httpd.extraModules = [
# note that order is *super* important here
{ name = "dav_svn"; path = "${pkgs.apacheHttpdPackages.subversion}/modules/mod_dav_svn.so"; }
{ name = "authz_svn"; path = "${pkgs.apacheHttpdPackages.subversion}/modules/mod_authz_svn.so"; }
];
services.httpd.virtualHosts = {
"svn" = {
hostName = HOSTNAME;
documentRoot = DOCUMENTROOT;
locations."/svn".extraConfig = ''
DAV svn
SVNParentPath REPO_PARENT
AuthzSVNAccessFile ACCESS_FILE
AuthName "SVN Repositories"
AuthType Basic
AuthUserFile PASSWORD_FILE
Require valid-user
'';
}
```
The key `"svn"` is just a symbolic name identifying the virtual host.
The `"/svn"` in `locations."/svn".extraConfig` is the path underneath
which the repositories will be served.
[This page](https://wiki.archlinux.org/index.php/Subversion) explains
how to set up the Subversion configuration itself. This boils down to
the following:
Underneath `REPO_PARENT` repositories can be set up as follows:
```ShellSession
$ svn create REPO_NAME
```
Repository files need to be accessible by `wwwrun`:
```ShellSession
$ chown -R wwwrun:wwwrun REPO_PARENT
```
The password file `PASSWORD_FILE` can be created as follows:
```ShellSession
$ htpasswd -cs PASSWORD_FILE USER_NAME
```
Additional users can be set up similarly, omitting the `c` flag:
```ShellSession
$ htpasswd -s PASSWORD_FILE USER_NAME
```
The file describing access permissions `ACCESS_FILE` will look something
like the following:
```nix
[/]
* = r
[REPO_NAME:/]
USER_NAME = rw
```
The Subversion repositories will be accessible as
`http://HOSTNAME/svn/REPO_NAME`.

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@ -1,140 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="module-services-subversion">
<title>Subversion</title>
<para>
<link xlink:href="https://subversion.apache.org/">Subversion</link>
is a centralized version-control system. It can use a <link
xlink:href="http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.choosing">variety
of protocols</link> for communication between client and server.
</para>
<section xml:id="module-services-subversion-apache-httpd">
<title>Subversion inside Apache HTTP</title>
<para>
This section focuses on configuring a web-based server on top of
the Apache HTTP server, which uses
<link xlink:href="http://www.webdav.org/">WebDAV</link>/<link
xlink:href="http://www.webdav.org/deltav/WWW10/deltav-intro.htm">DeltaV</link>
for communication.
</para>
<para>For more information on the general setup, please refer to
the <link
xlink:href="http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.httpd">the
appropriate section of the Subversion book</link>.
</para>
<para>To configure, include in
<literal>/etc/nixos/configuration.nix</literal> code to activate
Apache HTTP, setting <xref linkend="opt-services.httpd.adminAddr" />
appropriately:
</para>
<para>
<programlisting>
services.httpd.enable = true;
services.httpd.adminAddr = ...;
networking.firewall.allowedTCPPorts = [ 80 443 ];
</programlisting>
</para>
<para>For a simple Subversion server with basic authentication,
configure the Subversion module for Apache as follows, setting
<literal>hostName</literal> and <literal>documentRoot</literal>
appropriately, and <literal>SVNParentPath</literal> to the parent
directory of the repositories,
<literal>AuthzSVNAccessFile</literal> to the location of the
<code>.authz</code> file describing access permission, and
<literal>AuthUserFile</literal> to the password file.
</para>
<para>
<programlisting>
services.httpd.extraModules = [
# note that order is *super* important here
{ name = "dav_svn"; path = "${pkgs.apacheHttpdPackages.subversion}/modules/mod_dav_svn.so"; }
{ name = "authz_svn"; path = "${pkgs.apacheHttpdPackages.subversion}/modules/mod_authz_svn.so"; }
];
services.httpd.virtualHosts = {
"svn" = {
hostName = HOSTNAME;
documentRoot = DOCUMENTROOT;
locations."/svn".extraConfig = ''
DAV svn
SVNParentPath REPO_PARENT
AuthzSVNAccessFile ACCESS_FILE
AuthName "SVN Repositories"
AuthType Basic
AuthUserFile PASSWORD_FILE
Require valid-user
'';
}
</programlisting>
</para>
<para>
The key <code>"svn"</code> is just a symbolic name identifying the
virtual host. The <code>"/svn"</code> in
<code>locations."/svn".extraConfig</code> is the path underneath
which the repositories will be served.
</para>
<para><link
xlink:href="https://wiki.archlinux.org/index.php/Subversion">This
page</link> explains how to set up the Subversion configuration
itself. This boils down to the following:
</para>
<para>
Underneath <literal>REPO_PARENT</literal> repositories can be set up
as follows:
</para>
<para>
<screen>
<prompt>$ </prompt> svn create REPO_NAME
</screen>
</para>
<para>Repository files need to be accessible by
<literal>wwwrun</literal>:
</para>
<para>
<screen>
<prompt>$ </prompt> chown -R wwwrun:wwwrun REPO_PARENT
</screen>
</para>
<para>
The password file <literal>PASSWORD_FILE</literal> can be created as follows:
</para>
<para>
<screen>
<prompt>$ </prompt> htpasswd -cs PASSWORD_FILE USER_NAME
</screen>
</para>
<para>
Additional users can be set up similarly, omitting the
<code>c</code> flag:
</para>
<para>
<screen>
<prompt>$ </prompt> htpasswd -s PASSWORD_FILE USER_NAME
</screen>
</para>
<para>
The file describing access permissions
<literal>ACCESS_FILE</literal> will look something like
the following:
</para>
<para>
<programlisting>
[/]
* = r
[REPO_NAME:/]
USER_NAME = rw
</programlisting>
</para>
<para>The Subversion repositories will be accessible as <code>http://HOSTNAME/svn/REPO_NAME</code>.</para>
</section>
</chapter>

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@ -0,0 +1,92 @@
# User Management {#sec-user-management}
NixOS supports both declarative and imperative styles of user
management. In the declarative style, users are specified in
`configuration.nix`. For instance, the following states that a user
account named `alice` shall exist:
```nix
users.users.alice = {
isNormalUser = true;
home = "/home/alice";
description = "Alice Foobar";
extraGroups = [ "wheel" "networkmanager" ];
openssh.authorizedKeys.keys = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
};
```
Note that `alice` is a member of the `wheel` and `networkmanager`
groups, which allows her to use `sudo` to execute commands as `root` and
to configure the network, respectively. Also note the SSH public key
that allows remote logins with the corresponding private key. Users
created in this way do not have a password by default, so they cannot
log in via mechanisms that require a password. However, you can use the
`passwd` program to set a password, which is retained across invocations
of `nixos-rebuild`.
If you set [](#opt-users.mutableUsers) to
false, then the contents of `/etc/passwd` and `/etc/group` will be congruent
to your NixOS configuration. For instance, if you remove a user from
[](#opt-users.users) and run nixos-rebuild, the user
account will cease to exist. Also, imperative commands for managing users and
groups, such as useradd, are no longer available. Passwords may still be
assigned by setting the user\'s
[hashedPassword](#opt-users.users._name_.hashedPassword) option. A
hashed password can be generated using `mkpasswd -m
sha-512`.
A user ID (uid) is assigned automatically. You can also specify a uid
manually by adding
```nix
uid = 1000;
```
to the user specification.
Groups can be specified similarly. The following states that a group
named `students` shall exist:
```nix
users.groups.students.gid = 1000;
```
As with users, the group ID (gid) is optional and will be assigned
automatically if it's missing.
In the imperative style, users and groups are managed by commands such
as `useradd`, `groupmod` and so on. For instance, to create a user
account named `alice`:
```ShellSession
# useradd -m alice
```
To make all nix tools available to this new user use \`su - USER\` which
opens a login shell (==shell that loads the profile) for given user.
This will create the \~/.nix-defexpr symlink. So run:
```ShellSession
# su - alice -c "true"
```
The flag `-m` causes the creation of a home directory for the new user,
which is generally what you want. The user does not have an initial
password and therefore cannot log in. A password can be set using the
`passwd` utility:
```ShellSession
# passwd alice
Enter new UNIX password: ***
Retype new UNIX password: ***
```
A user can be deleted using `userdel`:
```ShellSession
# userdel -r alice
```
The flag `-r` deletes the user's home directory. Accounts can be
modified using `usermod`. Unix groups can be managed using `groupadd`,
`groupmod` and `groupdel`.

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@ -1,88 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-user-management">
<title>User Management</title>
<para>
NixOS supports both declarative and imperative styles of user management. In
the declarative style, users are specified in
<filename>configuration.nix</filename>. For instance, the following states
that a user account named <literal>alice</literal> shall exist:
<programlisting>
<xref linkend="opt-users.users"/>.alice = {
<link linkend="opt-users.users._name_.isNormalUser">isNormalUser</link> = true;
<link linkend="opt-users.users._name_.home">home</link> = "/home/alice";
<link linkend="opt-users.users._name_.description">description</link> = "Alice Foobar";
<link linkend="opt-users.users._name_.extraGroups">extraGroups</link> = [ "wheel" "networkmanager" ];
<link linkend="opt-users.users._name_.openssh.authorizedKeys.keys">openssh.authorizedKeys.keys</link> = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
};
</programlisting>
Note that <literal>alice</literal> is a member of the
<literal>wheel</literal> and <literal>networkmanager</literal> groups, which
allows her to use <command>sudo</command> to execute commands as
<literal>root</literal> and to configure the network, respectively. Also note
the SSH public key that allows remote logins with the corresponding private
key. Users created in this way do not have a password by default, so they
cannot log in via mechanisms that require a password. However, you can use
the <command>passwd</command> program to set a password, which is retained
across invocations of <command>nixos-rebuild</command>.
</para>
<para>
If you set <xref linkend="opt-users.mutableUsers"/> to false, then the
contents of <literal>/etc/passwd</literal> and <literal>/etc/group</literal>
will be congruent to your NixOS configuration. For instance, if you remove a
user from <xref linkend="opt-users.users"/> and run nixos-rebuild, the user
account will cease to exist. Also, imperative commands for managing users and
groups, such as useradd, are no longer available. Passwords may still be
assigned by setting the user's
<link linkend="opt-users.users._name_.hashedPassword">hashedPassword</link>
option. A hashed password can be generated using <command>mkpasswd -m
sha-512</command>.
</para>
<para>
A user ID (uid) is assigned automatically. You can also specify a uid
manually by adding
<programlisting>
uid = 1000;
</programlisting>
to the user specification.
</para>
<para>
Groups can be specified similarly. The following states that a group named
<literal>students</literal> shall exist:
<programlisting>
<xref linkend="opt-users.groups"/>.students.gid = 1000;
</programlisting>
As with users, the group ID (gid) is optional and will be assigned
automatically if its missing.
</para>
<para>
In the imperative style, users and groups are managed by commands such as
<command>useradd</command>, <command>groupmod</command> and so on. For
instance, to create a user account named <literal>alice</literal>:
<screen>
<prompt># </prompt>useradd -m <replaceable>alice</replaceable></screen>
To make all nix tools available to this new user use `su - USER` which opens
a login shell (==shell that loads the profile) for given user. This will
create the ~/.nix-defexpr symlink. So run:
<screen>
<prompt># </prompt>su - <replaceable>alice</replaceable> -c "true"</screen>
The flag <option>-m</option> causes the creation of a home directory for the
new user, which is generally what you want. The user does not have an initial
password and therefore cannot log in. A password can be set using the
<command>passwd</command> utility:
<screen>
<prompt># </prompt>passwd <replaceable>alice</replaceable>
Enter new UNIX password: ***
Retype new UNIX password: ***
</screen>
A user can be deleted using <command>userdel</command>:
<screen>
<prompt># </prompt>userdel -r <replaceable>alice</replaceable></screen>
The flag <option>-r</option> deletes the users home directory. Accounts
can be modified using <command>usermod</command>. Unix groups can be managed
using <command>groupadd</command>, <command>groupmod</command> and
<command>groupdel</command>.
</para>
</chapter>

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@ -0,0 +1,27 @@
# Wayland {#sec-wayland}
While X11 (see [](#sec-x11)) is still the primary display technology
on NixOS, Wayland support is steadily improving. Where X11 separates the
X Server and the window manager, on Wayland those are combined: a
Wayland Compositor is like an X11 window manager, but also embeds the
Wayland \'Server\' functionality. This means it is sufficient to install
a Wayland Compositor such as sway without separately enabling a Wayland
server:
```nix
programs.sway.enable = true;
```
This installs the sway compositor along with some essential utilities.
Now you can start sway from the TTY console.
If you are using a wlroots-based compositor, like sway, and want to be
able to share your screen, you might want to activate this option:
```nix
xdg.portal.wlr.enable = true;
```
and configure Pipewire using
[](#opt-services.pipewire.enable)
and related options.

View File

@ -1,33 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-wayland">
<title>Wayland</title>
<para>
While X11 (see <xref linkend="sec-x11"/>) is still the primary display
technology on NixOS, Wayland support is steadily improving.
Where X11 separates the X Server and the window manager, on Wayland those
are combined: a Wayland Compositor is like an X11 window manager, but also
embeds the Wayland 'Server' functionality. This means it is sufficient to
install a Wayland Compositor such as <package>sway</package> without
separately enabling a Wayland server:
<programlisting>
<xref linkend="opt-programs.sway.enable"/> = true;
</programlisting>
This installs the <package>sway</package> compositor along with some
essential utilities. Now you can start <package>sway</package> from the TTY
console.
</para>
<para>
If you are using a wlroots-based compositor, like sway, and want to be able to
share your screen, you might want to activate this option:
<programlisting>
<xref linkend="opt-xdg.portal.wlr.enable"/> = true;
</programlisting>
and configure Pipewire using <xref linkend="opt-services.pipewire.enable"/>
and related options.
</para>
</chapter>

View File

@ -0,0 +1,337 @@
# X Window System {#sec-x11}
The X Window System (X11) provides the basis of NixOS' graphical user
interface. It can be enabled as follows:
```nix
services.xserver.enable = true;
```
The X server will automatically detect and use the appropriate video
driver from a set of X.org drivers (such as `vesa` and `intel`). You can
also specify a driver manually, e.g.
```nix
services.xserver.videoDrivers = [ "r128" ];
```
to enable X.org's `xf86-video-r128` driver.
You also need to enable at least one desktop or window manager.
Otherwise, you can only log into a plain undecorated `xterm` window.
Thus you should pick one or more of the following lines:
```nix
services.xserver.desktopManager.plasma5.enable = true;
services.xserver.desktopManager.xfce.enable = true;
services.xserver.desktopManager.gnome.enable = true;
services.xserver.desktopManager.mate.enable = true;
services.xserver.windowManager.xmonad.enable = true;
services.xserver.windowManager.twm.enable = true;
services.xserver.windowManager.icewm.enable = true;
services.xserver.windowManager.i3.enable = true;
services.xserver.windowManager.herbstluftwm.enable = true;
```
NixOS's default *display manager* (the program that provides a graphical
login prompt and manages the X server) is LightDM. You can select an
alternative one by picking one of the following lines:
```nix
services.xserver.displayManager.sddm.enable = true;
services.xserver.displayManager.gdm.enable = true;
```
You can set the keyboard layout (and optionally the layout variant):
```nix
services.xserver.layout = "de";
services.xserver.xkbVariant = "neo";
```
The X server is started automatically at boot time. If you don't want
this to happen, you can set:
```nix
services.xserver.autorun = false;
```
The X server can then be started manually:
```ShellSession
# systemctl start display-manager.service
```
On 64-bit systems, if you want OpenGL for 32-bit programs such as in
Wine, you should also set the following:
```nix
hardware.opengl.driSupport32Bit = true;
```
## Auto-login {#sec-x11-auto-login .unnumbered}
The x11 login screen can be skipped entirely, automatically logging you
into your window manager and desktop environment when you boot your
computer.
This is especially helpful if you have disk encryption enabled. Since
you already have to provide a password to decrypt your disk, entering a
second password to login can be redundant.
To enable auto-login, you need to define your default window manager and
desktop environment. If you wanted no desktop environment and i3 as your
your window manager, you\'d define:
```nix
services.xserver.displayManager.defaultSession = "none+i3";
```
Every display manager in NixOS supports auto-login, here is an example
using lightdm for a user `alice`:
```nix
services.xserver.displayManager.lightdm.enable = true;
services.xserver.displayManager.autoLogin.enable = true;
services.xserver.displayManager.autoLogin.user = "alice";
```
## Intel Graphics drivers {#sec-x11--graphics-cards-intel .unnumbered}
There are two choices for Intel Graphics drivers in X.org: `modesetting`
(included in the xorg-server itself) and `intel` (provided by the
package xf86-video-intel).
The default and recommended is `modesetting`. It is a generic driver
which uses the kernel [mode
setting](https://en.wikipedia.org/wiki/Mode_setting) (KMS) mechanism. It
supports Glamor (2D graphics acceleration via OpenGL) and is actively
maintained but may perform worse in some cases (like in old chipsets).
The second driver, `intel`, is specific to Intel GPUs, but not
recommended by most distributions: it lacks several modern features (for
example, it doesn\'t support Glamor) and the package hasn\'t been
officially updated since 2015.
The results vary depending on the hardware, so you may have to try both
drivers. Use the option
[](#opt-services.xserver.videoDrivers)
to set one. The recommended configuration for modern systems is:
```nix
services.xserver.videoDrivers = [ "modesetting" ];
services.xserver.useGlamor = true;
```
If you experience screen tearing no matter what, this configuration was
reported to resolve the issue:
```nix
services.xserver.videoDrivers = [ "intel" ];
services.xserver.deviceSection = ''
Option "DRI" "2"
Option "TearFree" "true"
'';
```
Note that this will likely downgrade the performance compared to
`modesetting` or `intel` with DRI 3 (default).
## Proprietary NVIDIA drivers {#sec-x11-graphics-cards-nvidia .unnumbered}
NVIDIA provides a proprietary driver for its graphics cards that has
better 3D performance than the X.org drivers. It is not enabled by
default because it's not free software. You can enable it as follows:
```nix
services.xserver.videoDrivers = [ "nvidia" ];
```
Or if you have an older card, you may have to use one of the legacy
drivers:
```nix
services.xserver.videoDrivers = [ "nvidiaLegacy390" ];
services.xserver.videoDrivers = [ "nvidiaLegacy340" ];
services.xserver.videoDrivers = [ "nvidiaLegacy304" ];
```
You may need to reboot after enabling this driver to prevent a clash
with other kernel modules.
## Proprietary AMD drivers {#sec-x11--graphics-cards-amd .unnumbered}
AMD provides a proprietary driver for its graphics cards that is not
enabled by default because it's not Free Software, is often broken in
nixpkgs and as of this writing doesn\'t offer more features or
performance. If you still want to use it anyway, you need to explicitly
set:
```nix
services.xserver.videoDrivers = [ "amdgpu-pro" ];
```
You will need to reboot after enabling this driver to prevent a clash
with other kernel modules.
## Touchpads {#sec-x11-touchpads .unnumbered}
Support for Synaptics touchpads (found in many laptops such as the Dell
Latitude series) can be enabled as follows:
```nix
services.xserver.libinput.enable = true;
```
The driver has many options (see [](#ch-options)).
For instance, the following disables tap-to-click behavior:
```nix
services.xserver.libinput.touchpad.tapping = false;
```
Note: the use of `services.xserver.synaptics` is deprecated since NixOS
17.09.
## GTK/Qt themes {#sec-x11-gtk-and-qt-themes .unnumbered}
GTK themes can be installed either to user profile or system-wide (via
`environment.systemPackages`). To make Qt 5 applications look similar to
GTK ones, you can use the following configuration:
```nix
qt5.enable = true;
qt5.platformTheme = "gtk2";
qt5.style = "gtk2";
```
## Custom XKB layouts {#custom-xkb-layouts .unnumbered}
It is possible to install custom [ XKB
](https://en.wikipedia.org/wiki/X_keyboard_extension) keyboard layouts
using the option `services.xserver.extraLayouts`.
As a first example, we are going to create a layout based on the basic
US layout, with an additional layer to type some greek symbols by
pressing the right-alt key.
Create a file called `us-greek` with the following content (under a
directory called `symbols`; it\'s an XKB peculiarity that will help with
testing):
```nix
xkb_symbols "us-greek"
{
include "us(basic)" // includes the base US keys
include "level3(ralt_switch)" // configures right alt as a third level switch
key <LatA> { [ a, A, Greek_alpha ] };
key <LatB> { [ b, B, Greek_beta ] };
key <LatG> { [ g, G, Greek_gamma ] };
key <LatD> { [ d, D, Greek_delta ] };
key <LatZ> { [ z, Z, Greek_zeta ] };
};
```
A minimal layout specification must include the following:
```nix
services.xserver.extraLayouts.us-greek = {
description = "US layout with alt-gr greek";
languages = [ "eng" ];
symbolsFile = /yourpath/symbols/us-greek;
};
```
::: {.note}
The name (after `extraLayouts.`) should match the one given to the
`xkb_symbols` block.
:::
Applying this customization requires rebuilding several packages, and a
broken XKB file can lead to the X session crashing at login. Therefore,
you\'re strongly advised to **test your layout before applying it**:
```ShellSession
$ nix-shell -p xorg.xkbcomp
$ setxkbmap -I/yourpath us-greek -print | xkbcomp -I/yourpath - $DISPLAY
```
You can inspect the predefined XKB files for examples:
```ShellSession
$ echo "$(nix-build --no-out-link '<nixpkgs>' -A xorg.xkeyboardconfig)/etc/X11/xkb/"
```
Once the configuration is applied, and you did a logout/login cycle, the
layout should be ready to use. You can try it by e.g. running
`setxkbmap us-greek` and then type `<alt>+a` (it may not get applied in
your terminal straight away). To change the default, the usual
`services.xserver.layout` option can still be used.
A layout can have several other components besides `xkb_symbols`, for
example we will define new keycodes for some multimedia key and bind
these to some symbol.
Use the *xev* utility from `pkgs.xorg.xev` to find the codes of the keys
of interest, then create a `media-key` file to hold the keycodes
definitions
```nix
xkb_keycodes "media"
{
<volUp> = 123;
<volDown> = 456;
}
```
Now use the newly define keycodes in `media-sym`:
```nix
xkb_symbols "media"
{
key.type = "ONE_LEVEL";
key <volUp> { [ XF86AudioLowerVolume ] };
key <volDown> { [ XF86AudioRaiseVolume ] };
}
```
As before, to install the layout do
```nix
services.xserver.extraLayouts.media = {
description = "Multimedia keys remapping";
languages = [ "eng" ];
symbolsFile = /path/to/media-key;
keycodesFile = /path/to/media-sym;
};
```
::: {.note}
The function `pkgs.writeText <filename> <content>` can be useful if you
prefer to keep the layout definitions inside the NixOS configuration.
:::
Unfortunately, the Xorg server does not (currently) support setting a
keymap directly but relies instead on XKB rules to select the matching
components (keycodes, types, \...) of a layout. This means that
components other than symbols won\'t be loaded by default. As a
workaround, you can set the keymap using `setxkbmap` at the start of the
session with:
```nix
services.xserver.displayManager.sessionCommands = "setxkbmap -keycodes media";
```
If you are manually starting the X server, you should set the argument
`-xkbdir /etc/X11/xkb`, otherwise X won\'t find your layout files. For
example with `xinit` run
```ShellSession
$ xinit -- -xkbdir /etc/X11/xkb
```
To learn how to write layouts take a look at the XKB [documentation
](https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts).
More example layouts can also be found [here
](https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples).

View File

@ -1,355 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-x11">
<title>X Window System</title>
<para>
The X Window System (X11) provides the basis of NixOS graphical user
interface. It can be enabled as follows:
<programlisting>
<xref linkend="opt-services.xserver.enable"/> = true;
</programlisting>
The X server will automatically detect and use the appropriate video driver
from a set of X.org drivers (such as <literal>vesa</literal> and
<literal>intel</literal>). You can also specify a driver manually, e.g.
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "r128" ];
</programlisting>
to enable X.orgs <literal>xf86-video-r128</literal> driver.
</para>
<para>
You also need to enable at least one desktop or window manager. Otherwise,
you can only log into a plain undecorated <command>xterm</command> window.
Thus you should pick one or more of the following lines:
<programlisting>
<xref linkend="opt-services.xserver.desktopManager.plasma5.enable"/> = true;
<xref linkend="opt-services.xserver.desktopManager.xfce.enable"/> = true;
<xref linkend="opt-services.xserver.desktopManager.gnome.enable"/> = true;
<xref linkend="opt-services.xserver.desktopManager.mate.enable"/> = true;
<xref linkend="opt-services.xserver.windowManager.xmonad.enable"/> = true;
<xref linkend="opt-services.xserver.windowManager.twm.enable"/> = true;
<xref linkend="opt-services.xserver.windowManager.icewm.enable"/> = true;
<xref linkend="opt-services.xserver.windowManager.i3.enable"/> = true;
<xref linkend="opt-services.xserver.windowManager.herbstluftwm.enable"/> = true;
</programlisting>
</para>
<para>
NixOSs default <emphasis>display manager</emphasis> (the program that
provides a graphical login prompt and manages the X server) is LightDM. You
can select an alternative one by picking one of the following lines:
<programlisting>
<xref linkend="opt-services.xserver.displayManager.sddm.enable"/> = true;
<xref linkend="opt-services.xserver.displayManager.gdm.enable"/> = true;
</programlisting>
</para>
<para>
You can set the keyboard layout (and optionally the layout variant):
<programlisting>
<xref linkend="opt-services.xserver.layout"/> = "de";
<xref linkend="opt-services.xserver.xkbVariant"/> = "neo";
</programlisting>
</para>
<para>
The X server is started automatically at boot time. If you dont want this
to happen, you can set:
<programlisting>
<xref linkend="opt-services.xserver.autorun"/> = false;
</programlisting>
The X server can then be started manually:
<screen>
<prompt># </prompt>systemctl start display-manager.service
</screen>
</para>
<para>
On 64-bit systems, if you want OpenGL for 32-bit programs such as in Wine,
you should also set the following:
<programlisting>
<xref linkend="opt-hardware.opengl.driSupport32Bit"/> = true;
</programlisting>
</para>
<simplesect xml:id="sec-x11-auto-login">
<title>Auto-login</title>
<para>
The x11 login screen can be skipped entirely, automatically logging you into
your window manager and desktop environment when you boot your computer.
</para>
<para>
This is especially helpful if you have disk encryption enabled. Since you
already have to provide a password to decrypt your disk, entering a second
password to login can be redundant.
</para>
<para>
To enable auto-login, you need to define your default window manager and
desktop environment. If you wanted no desktop environment and i3 as your your
window manager, you'd define:
<programlisting>
<xref linkend="opt-services.xserver.displayManager.defaultSession"/> = "none+i3";
</programlisting>
Every display manager in NixOS supports auto-login, here is an example
using lightdm for a user <literal>alice</literal>:
<programlisting>
<xref linkend="opt-services.xserver.displayManager.lightdm.enable"/> = true;
<xref linkend="opt-services.xserver.displayManager.autoLogin.enable"/> = true;
<xref linkend="opt-services.xserver.displayManager.autoLogin.user"/> = "alice";
</programlisting>
</para>
</simplesect>
<simplesect xml:id="sec-x11--graphics-cards-intel">
<title>Intel Graphics drivers</title>
<para>
There are two choices for Intel Graphics drivers in X.org:
<literal>modesetting</literal> (included in the <package>xorg-server</package> itself)
and <literal>intel</literal> (provided by the package <package>xf86-video-intel</package>).
</para>
<para>
The default and recommended is <literal>modesetting</literal>.
It is a generic driver which uses the kernel
<link xlink:href="https://en.wikipedia.org/wiki/Mode_setting">mode setting</link>
(KMS) mechanism. It supports Glamor (2D graphics acceleration via OpenGL)
and is actively maintained but may perform worse in some cases (like in old chipsets).
</para>
<para>
The second driver, <literal>intel</literal>, is specific to Intel GPUs,
but not recommended by most distributions: it lacks several modern features
(for example, it doesn't support Glamor) and the package hasn't been officially
updated since 2015.
</para>
<para>
The results vary depending on the hardware, so you may have to try both drivers.
Use the option <xref linkend="opt-services.xserver.videoDrivers"/> to set one.
The recommended configuration for modern systems is:
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "modesetting" ];
<xref linkend="opt-services.xserver.useGlamor"/> = true;
</programlisting>
If you experience screen tearing no matter what, this configuration was
reported to resolve the issue:
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "intel" ];
<xref linkend="opt-services.xserver.deviceSection"/> = ''
Option "DRI" "2"
Option "TearFree" "true"
'';
</programlisting>
Note that this will likely downgrade the performance compared to
<literal>modesetting</literal> or <literal>intel</literal> with DRI 3 (default).
</para>
</simplesect>
<simplesect xml:id="sec-x11-graphics-cards-nvidia">
<title>Proprietary NVIDIA drivers</title>
<para>
NVIDIA provides a proprietary driver for its graphics cards that has better
3D performance than the X.org drivers. It is not enabled by default because
its not free software. You can enable it as follows:
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "nvidia" ];
</programlisting>
Or if you have an older card, you may have to use one of the legacy drivers:
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "nvidiaLegacy390" ];
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "nvidiaLegacy340" ];
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "nvidiaLegacy304" ];
</programlisting>
You may need to reboot after enabling this driver to prevent a clash with
other kernel modules.
</para>
</simplesect>
<simplesect xml:id="sec-x11--graphics-cards-amd">
<title>Proprietary AMD drivers</title>
<para>
AMD provides a proprietary driver for its graphics cards that is not
enabled by default because its not Free Software, is often broken
in nixpkgs and as of this writing doesn't offer more features or
performance. If you still want to use it anyway, you need to explicitly set:
<programlisting>
<xref linkend="opt-services.xserver.videoDrivers"/> = [ "amdgpu-pro" ];
</programlisting>
You will need to reboot after enabling this driver to prevent a clash with
other kernel modules.
</para>
</simplesect>
<simplesect xml:id="sec-x11-touchpads">
<title>Touchpads</title>
<para>
Support for Synaptics touchpads (found in many laptops such as the Dell
Latitude series) can be enabled as follows:
<programlisting>
<xref linkend="opt-services.xserver.libinput.enable"/> = true;
</programlisting>
The driver has many options (see <xref linkend="ch-options"/>). For
instance, the following disables tap-to-click behavior:
<programlisting>
<xref linkend="opt-services.xserver.libinput.touchpad.tapping"/> = false;
</programlisting>
Note: the use of <literal>services.xserver.synaptics</literal> is deprecated
since NixOS 17.09.
</para>
</simplesect>
<simplesect xml:id="sec-x11-gtk-and-qt-themes">
<title>GTK/Qt themes</title>
<para>
GTK themes can be installed either to user profile or system-wide (via
<literal>environment.systemPackages</literal>). To make Qt 5 applications
look similar to GTK ones, you can use the following configuration:
<programlisting>
<xref linkend="opt-qt5.enable"/> = true;
<xref linkend="opt-qt5.platformTheme"/> = "gtk2";
<xref linkend="opt-qt5.style"/> = "gtk2";
</programlisting>
</para>
</simplesect>
<simplesect xml:id="custom-xkb-layouts">
<title>Custom XKB layouts</title>
<para>
It is possible to install custom
<link xlink:href="https://en.wikipedia.org/wiki/X_keyboard_extension">
XKB
</link>
keyboard layouts using the option
<option><link linkend="opt-services.xserver.extraLayouts">
services.xserver.extraLayouts</link></option>.
</para>
<para>
As a first example, we are going to create a layout based on the basic US
layout, with an additional layer to type some greek symbols by pressing the
right-alt key.
</para>
<para>
Create a file called <literal>us-greek</literal> with the following
content (under a directory called <literal>symbols</literal>; it's
an XKB peculiarity that will help with testing):
</para>
<programlisting>
xkb_symbols &quot;us-greek&quot;
{
include &quot;us(basic)&quot; // includes the base US keys
include &quot;level3(ralt_switch)&quot; // configures right alt as a third level switch
key &lt;LatA&gt; { [ a, A, Greek_alpha ] };
key &lt;LatB&gt; { [ b, B, Greek_beta ] };
key &lt;LatG&gt; { [ g, G, Greek_gamma ] };
key &lt;LatD&gt; { [ d, D, Greek_delta ] };
key &lt;LatZ&gt; { [ z, Z, Greek_zeta ] };
};
</programlisting>
<para>
A minimal layout specification must include the following:
</para>
<programlisting>
<xref linkend="opt-services.xserver.extraLayouts"/>.us-greek = {
description = "US layout with alt-gr greek";
languages = [ "eng" ];
symbolsFile = /yourpath/symbols/us-greek;
};
</programlisting>
<note>
<para>
The name (after <literal>extraLayouts.</literal>) should match the one given to the
<literal>xkb_symbols</literal> block.
</para>
</note>
<para>
Applying this customization requires rebuilding several packages,
and a broken XKB file can lead to the X session crashing at login.
Therefore, you're strongly advised to <emphasis role="strong">test
your layout before applying it</emphasis>:
<screen>
<prompt>$ </prompt>nix-shell -p xorg.xkbcomp
<prompt>$ </prompt>setxkbmap -I/yourpath us-greek -print | xkbcomp -I/yourpath - $DISPLAY
</screen>
</para>
<para>
You can inspect the predefined XKB files for examples:
<screen>
<prompt>$ </prompt>echo "$(nix-build --no-out-link '&lt;nixpkgs&gt;' -A xorg.xkeyboardconfig)/etc/X11/xkb/"
</screen>
</para>
<para>
Once the configuration is applied, and you did a logout/login
cycle, the layout should be ready to use. You can try it by e.g.
running <literal>setxkbmap us-greek</literal> and then type
<literal>&lt;alt&gt;+a</literal> (it may not get applied in your
terminal straight away). To change the default, the usual
<option>
<link linkend="opt-services.xserver.layout">
services.xserver.layout
</link>
</option>
option can still be used.
</para>
<para>
A layout can have several other components besides
<literal>xkb_symbols</literal>, for example we will define new
keycodes for some multimedia key and bind these to some symbol.
</para>
<para>
Use the <emphasis>xev</emphasis> utility from
<literal>pkgs.xorg.xev</literal> to find the codes of the keys of
interest, then create a <literal>media-key</literal> file to hold
the keycodes definitions
</para>
<programlisting>
xkb_keycodes &quot;media&quot;
{
&lt;volUp&gt; = 123;
&lt;volDown&gt; = 456;
}
</programlisting>
<para>
Now use the newly define keycodes in <literal>media-sym</literal>:
</para>
<programlisting>
xkb_symbols &quot;media&quot;
{
key.type = &quot;ONE_LEVEL&quot;;
key &lt;volUp&gt; { [ XF86AudioLowerVolume ] };
key &lt;volDown&gt; { [ XF86AudioRaiseVolume ] };
}
</programlisting>
<para>
As before, to install the layout do
</para>
<programlisting>
<xref linkend="opt-services.xserver.extraLayouts"/>.media = {
description = "Multimedia keys remapping";
languages = [ "eng" ];
symbolsFile = /path/to/media-key;
keycodesFile = /path/to/media-sym;
};
</programlisting>
<note>
<para>
The function <literal>pkgs.writeText &lt;filename&gt; &lt;content&gt;
</literal> can be useful if you prefer to keep the layout definitions
inside the NixOS configuration.
</para>
</note>
<para>
Unfortunately, the Xorg server does not (currently) support setting a
keymap directly but relies instead on XKB rules to select the matching
components (keycodes, types, ...) of a layout. This means that components
other than symbols won't be loaded by default. As a workaround, you
can set the keymap using <literal>setxkbmap</literal> at the start of the
session with:
</para>
<programlisting>
<xref linkend="opt-services.xserver.displayManager.sessionCommands"/> = "setxkbmap -keycodes media";
</programlisting>
<para>
If you are manually starting the X server, you should set the argument
<literal>-xkbdir /etc/X11/xkb</literal>, otherwise X won't find your layout files.
For example with <command>xinit</command> run
<screen><prompt>$ </prompt>xinit -- -xkbdir /etc/X11/xkb</screen>
</para>
<para>
To learn how to write layouts take a look at the XKB
<link xlink:href="https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts">
documentation
</link>. More example layouts can also be found
<link xlink:href="https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples">
here
</link>.
</para>
</simplesect>
</chapter>

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# Xfce Desktop Environment {#sec-xfce}
To enable the Xfce Desktop Environment, set
```nix
services.xserver.desktopManager.xfce.enable = true;
services.xserver.displayManager.defaultSession = "xfce";
```
Optionally, *picom* can be enabled for nice graphical effects, some
example settings:
```nix
services.picom = {
enable = true;
fade = true;
inactiveOpacity = 0.9;
shadow = true;
fadeDelta = 4;
};
```
Some Xfce programs are not installed automatically. To install them
manually (system wide), put them into your
[](#opt-environment.systemPackages) from `pkgs.xfce`.
## Thunar Plugins {#sec-xfce-thunar-plugins .unnumbered}
If you\'d like to add extra plugins to Thunar, add them to
[](#opt-services.xserver.desktopManager.xfce.thunarPlugins).
You shouldn\'t just add them to [](#opt-environment.systemPackages).
## Troubleshooting {#sec-xfce-troubleshooting .unnumbered}
Even after enabling udisks2, volume management might not work. Thunar
and/or the desktop takes time to show up. Thunar will spit out this kind
of message on start (look at `journalctl --user -b`).
```plain
Thunar:2410): GVFS-RemoteVolumeMonitor-WARNING **: remote volume monitor with dbus name org.gtk.Private.UDisks2VolumeMonitor is not supported
```
This is caused by some needed GNOME services not running. This is all
fixed by enabling \"Launch GNOME services on startup\" in the Advanced
tab of the Session and Startup settings panel. Alternatively, you can
run this command to do the same thing.
```ShellSession
$ xfconf-query -c xfce4-session -p /compat/LaunchGNOME -s true
```
A log-out and re-log will be needed for this to take effect.

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@ -1,59 +0,0 @@
<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-xfce">
<title>Xfce Desktop Environment</title>
<para>
To enable the Xfce Desktop Environment, set
<programlisting>
<xref linkend="opt-services.xserver.desktopManager.xfce.enable" /> = true;
<xref linkend="opt-services.xserver.displayManager.defaultSession" /> = "xfce";
</programlisting>
</para>
<para>
Optionally, <emphasis>picom</emphasis> can be enabled for nice graphical
effects, some example settings:
<programlisting>
<link linkend="opt-services.picom.enable">services.picom</link> = {
<link linkend="opt-services.picom.enable">enable</link> = true;
<link linkend="opt-services.picom.fade">fade</link> = true;
<link linkend="opt-services.picom.inactiveOpacity">inactiveOpacity</link> = 0.9;
<link linkend="opt-services.picom.shadow">shadow</link> = true;
<link linkend="opt-services.picom.fadeDelta">fadeDelta</link> = 4;
};
</programlisting>
</para>
<para>
Some Xfce programs are not installed automatically. To install them manually
(system wide), put them into your
<xref linkend="opt-environment.systemPackages"/> from <literal>pkgs.xfce</literal>.
</para>
<simplesect xml:id="sec-xfce-thunar-plugins">
<title>Thunar Plugins</title>
<para>
If you'd like to add extra plugins to Thunar, add them to
<xref linkend="opt-services.xserver.desktopManager.xfce.thunarPlugins"/>.
You shouldn't just add them to <xref linkend="opt-environment.systemPackages"/>.
</para>
</simplesect>
<simplesect xml:id="sec-xfce-troubleshooting">
<title>Troubleshooting</title>
<para>
Even after enabling udisks2, volume management might not work. Thunar and/or
the desktop takes time to show up. Thunar will spit out this kind of message
on start (look at <command>journalctl --user -b</command>).
<programlisting>
Thunar:2410): GVFS-RemoteVolumeMonitor-WARNING **: remote volume monitor with dbus name org.gtk.Private.UDisks2VolumeMonitor is not supported
</programlisting>
This is caused by some needed GNOME services not running. This is all fixed
by enabling "Launch GNOME services on startup" in the Advanced tab of the
Session and Startup settings panel. Alternatively, you can run this command
to do the same thing.
<programlisting>
<prompt>$ </prompt>xfconf-query -c xfce4-session -p /compat/LaunchGNOME -s true
</programlisting>
A log-out and re-log will be needed for this to take effect.
</para>
</simplesect>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-gpu-accel">
<title>GPU acceleration</title>
<para>
NixOS provides various APIs that benefit from GPU hardware
acceleration, such as VA-API and VDPAU for video playback; OpenGL
and Vulkan for 3D graphics; and OpenCL for general-purpose
computing. This chapter describes how to set up GPU hardware
acceleration (as far as this is not done automatically) and how to
verify that hardware acceleration is indeed used.
</para>
<para>
Most of the aforementioned APIs are agnostic with regards to which
display server is used. Consequently, these instructions should
apply both to the X Window System and Wayland compositors.
</para>
<section xml:id="sec-gpu-accel-opencl">
<title>OpenCL</title>
<para>
<link xlink:href="https://en.wikipedia.org/wiki/OpenCL">OpenCL</link>
is a general compute API. It is used by various applications such
as Blender and Darktable to accelerate certain operations.
</para>
<para>
OpenCL applications load drivers through the <emphasis>Installable
Client Driver</emphasis> (ICD) mechanism. In this mechanism, an
ICD file specifies the path to the OpenCL driver for a particular
GPU family. In NixOS, there are two ways to make ICD files visible
to the ICD loader. The first is through the
<literal>OCL_ICD_VENDORS</literal> environment variable. This
variable can contain a directory which is scanned by the ICL
loader for ICD files. For example:
</para>
<programlisting>
$ export \
OCL_ICD_VENDORS=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/
</programlisting>
<para>
The second mechanism is to add the OpenCL driver package to
<xref linkend="opt-hardware.opengl.extraPackages" />. This links
the ICD file under <literal>/run/opengl-driver</literal>, where it
will be visible to the ICD loader.
</para>
<para>
The proper installation of OpenCL drivers can be verified through
the <literal>clinfo</literal> command of the clinfo package. This
command will report the number of hardware devices that is found
and give detailed information for each device:
</para>
<programlisting>
$ clinfo | head -n3
Number of platforms 1
Platform Name AMD Accelerated Parallel Processing
Platform Vendor Advanced Micro Devices, Inc.
</programlisting>
<section xml:id="sec-gpu-accel-opencl-amd">
<title>AMD</title>
<para>
Modern AMD
<link xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
Core Next</link> (GCN) GPUs are supported through the
rocm-opencl-icd package. Adding this package to
<xref linkend="opt-hardware.opengl.extraPackages" /> enables
OpenCL support:
</para>
<programlisting language="bash">
hardware.opengl.extraPackages = [
rocm-opencl-icd
];
</programlisting>
</section>
<section xml:id="sec-gpu-accel-opencl-intel">
<title>Intel</title>
<para>
<link xlink:href="https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen8">Intel
Gen8 and later GPUs</link> are supported by the Intel NEO OpenCL
runtime that is provided by the intel-compute-runtime package.
For Gen7 GPUs, the deprecated Beignet runtime can be used, which
is provided by the beignet package. The proprietary Intel OpenCL
runtime, in the intel-ocl package, is an alternative for Gen7
GPUs.
</para>
<para>
The intel-compute-runtime, beignet, or intel-ocl package can be
added to <xref linkend="opt-hardware.opengl.extraPackages" /> to
enable OpenCL support. For example, for Gen8 and later GPUs, the
following configuration can be used:
</para>
<programlisting language="bash">
hardware.opengl.extraPackages = [
intel-compute-runtime
];
</programlisting>
</section>
</section>
<section xml:id="sec-gpu-accel-vulkan">
<title>Vulkan</title>
<para>
<link xlink:href="https://en.wikipedia.org/wiki/Vulkan_(API)">Vulkan</link>
is a graphics and compute API for GPUs. It is used directly by
games or indirectly though compatibility layers like
<link xlink:href="https://github.com/doitsujin/dxvk/wiki">DXVK</link>.
</para>
<para>
By default, if <xref linkend="opt-hardware.opengl.driSupport" />
is enabled, mesa is installed and provides Vulkan for supported
hardware.
</para>
<para>
Similar to OpenCL, Vulkan drivers are loaded through the
<emphasis>Installable Client Driver</emphasis> (ICD) mechanism.
ICD files for Vulkan are JSON files that specify the path to the
driver library and the supported Vulkan version. All successfully
loaded drivers are exposed to the application as different GPUs.
In NixOS, there are two ways to make ICD files visible to Vulkan
applications: an environment variable and a module option.
</para>
<para>
The first option is through the
<literal>VK_ICD_FILENAMES</literal> environment variable. This
variable can contain multiple JSON files, separated by
<literal>:</literal>. For example:
</para>
<programlisting>
$ export \
VK_ICD_FILENAMES=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json
</programlisting>
<para>
The second mechanism is to add the Vulkan driver package to
<xref linkend="opt-hardware.opengl.extraPackages" />. This links
the ICD file under <literal>/run/opengl-driver</literal>, where it
will be visible to the ICD loader.
</para>
<para>
The proper installation of Vulkan drivers can be verified through
the <literal>vulkaninfo</literal> command of the vulkan-tools
package. This command will report the hardware devices and drivers
found, in this example output amdvlk and radv:
</para>
<programlisting>
$ vulkaninfo | grep GPU
GPU id : 0 (Unknown AMD GPU)
GPU id : 1 (AMD RADV NAVI10 (LLVM 9.0.1))
...
GPU0:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
deviceName = Unknown AMD GPU
GPU1:
deviceType = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
</programlisting>
<para>
A simple graphical application that uses Vulkan is
<literal>vkcube</literal> from the vulkan-tools package.
</para>
<section xml:id="sec-gpu-accel-vulkan-amd">
<title>AMD</title>
<para>
Modern AMD
<link xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
Core Next</link> (GCN) GPUs are supported through either radv,
which is part of mesa, or the amdvlk package. Adding the amdvlk
package to <xref linkend="opt-hardware.opengl.extraPackages" />
makes amdvlk the default driver and hides radv and lavapipe from
the device list. A specific driver can be forced as follows:
</para>
<programlisting language="bash">
hardware.opengl.extraPackages = [
pkgs.amdvlk
];
# To enable Vulkan support for 32-bit applications, also add:
hardware.opengl.extraPackages32 = [
pkgs.driversi686Linux.amdvlk
];
# Force radv
environment.variables.AMD_VULKAN_ICD = &quot;RADV&quot;;
# Or
environment.variables.VK_ICD_FILENAMES =
&quot;/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json&quot;;
</programlisting>
</section>
</section>
<section xml:id="sec-gpu-accel-common-issues">
<title>Common issues</title>
<section xml:id="sec-gpu-accel-common-issues-permissions">
<title>User permissions</title>
<para>
Except where noted explicitly, it should not be necessary to
adjust user permissions to use these acceleration APIs. In the
default configuration, GPU devices have world-read/write
permissions (<literal>/dev/dri/renderD*</literal>) or are tagged
as <literal>uaccess</literal>
(<literal>/dev/dri/card*</literal>). The access control lists of
devices with the <literal>uaccess</literal> tag will be updated
automatically when a user logs in through
<literal>systemd-logind</literal>. For example, if the user
<emphasis>jane</emphasis> is logged in, the access control list
should look as follows:
</para>
<programlisting>
$ getfacl /dev/dri/card0
# file: dev/dri/card0
# owner: root
# group: video
user::rw-
user:jane:rw-
group::rw-
mask::rw-
other::---
</programlisting>
<para>
If you disabled (this functionality of)
<literal>systemd-logind</literal>, you may need to add the user
to the <literal>video</literal> group and log in again.
</para>
</section>
<section xml:id="sec-gpu-accel-common-issues-mixing-nixpkgs">
<title>Mixing different versions of nixpkgs</title>
<para>
The <emphasis>Installable Client Driver</emphasis> (ICD)
mechanism used by OpenCL and Vulkan loads runtimes into its
address space using <literal>dlopen</literal>. Mixing an ICD
loader mechanism and runtimes from different version of nixpkgs
may not work. For example, if the ICD loader uses an older
version of glibc than the runtime, the runtime may not be
loadable due to missing symbols. Unfortunately, the loader will
generally be quiet about such issues.
</para>
<para>
If you suspect that you are running into library version
mismatches between an ICL loader and a runtime, you could run an
application with the <literal>LD_DEBUG</literal> variable set to
get more diagnostic information. For example, OpenCL can be
tested with <literal>LD_DEBUG=files clinfo</literal>, which
should report missing symbols.
</para>
</section>
</section>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-kubernetes">
<title>Kubernetes</title>
<para>
The NixOS Kubernetes module is a collective term for a handful of
individual submodules implementing the Kubernetes cluster
components.
</para>
<para>
There are generally two ways of enabling Kubernetes on NixOS. One
way is to enable and configure cluster components appropriately by
hand:
</para>
<programlisting language="bash">
services.kubernetes = {
apiserver.enable = true;
controllerManager.enable = true;
scheduler.enable = true;
addonManager.enable = true;
proxy.enable = true;
flannel.enable = true;
};
</programlisting>
<para>
Another way is to assign cluster roles (&quot;master&quot; and/or
&quot;node&quot;) to the host. This enables apiserver,
controllerManager, scheduler, addonManager, kube-proxy and etcd:
</para>
<programlisting language="bash">
services.kubernetes.roles = [ &quot;master&quot; ];
</programlisting>
<para>
While this will enable the kubelet and kube-proxy only:
</para>
<programlisting language="bash">
services.kubernetes.roles = [ &quot;node&quot; ];
</programlisting>
<para>
Assigning both the master and node roles is usable if you want a
single node Kubernetes cluster for dev or testing purposes:
</para>
<programlisting language="bash">
services.kubernetes.roles = [ &quot;master&quot; &quot;node&quot; ];
</programlisting>
<para>
Note: Assigning either role will also default both
<xref linkend="opt-services.kubernetes.flannel.enable" /> and
<xref linkend="opt-services.kubernetes.easyCerts" /> to true. This
sets up flannel as CNI and activates automatic PKI bootstrapping.
</para>
<para>
As of kubernetes 1.10.X it has been deprecated to open
non-tls-enabled ports on kubernetes components. Thus, from NixOS
19.03 all plain HTTP ports have been disabled by default. While
opening insecure ports is still possible, it is recommended not to
bind these to other interfaces than loopback. To re-enable the
insecure port on the apiserver, see options:
<xref linkend="opt-services.kubernetes.apiserver.insecurePort" />
and
<xref linkend="opt-services.kubernetes.apiserver.insecureBindAddress" />
</para>
<note>
<para>
As of NixOS 19.03, it is mandatory to configure:
<xref linkend="opt-services.kubernetes.masterAddress" />. The
masterAddress must be resolveable and routeable by all cluster
nodes. In single node clusters, this can be set to
<literal>localhost</literal>.
</para>
</note>
<para>
Role-based access control (RBAC) authorization mode is enabled by
default. This means that anonymous requests to the apiserver secure
port will expectedly cause a permission denied error. All cluster
components must therefore be configured with x509 certificates for
two-way tls communication. The x509 certificate subject section
determines the roles and permissions granted by the apiserver to
perform clusterwide or namespaced operations. See also:
<link xlink:href="https://kubernetes.io/docs/reference/access-authn-authz/rbac/">
Using RBAC Authorization</link>.
</para>
<para>
The NixOS kubernetes module provides an option for automatic
certificate bootstrapping and configuration,
<xref linkend="opt-services.kubernetes.easyCerts" />. The PKI
bootstrapping process involves setting up a certificate authority
(CA) daemon (cfssl) on the kubernetes master node. cfssl generates a
CA-cert for the cluster, and uses the CA-cert for signing
subordinate certs issued to each of the cluster components.
Subsequently, the certmgr daemon monitors active certificates and
renews them when needed. For single node Kubernetes clusters,
setting <xref linkend="opt-services.kubernetes.easyCerts" /> = true
is sufficient and no further action is required. For joining extra
node machines to an existing cluster on the other hand, establishing
initial trust is mandatory.
</para>
<para>
To add new nodes to the cluster: On any (non-master) cluster node
where <xref linkend="opt-services.kubernetes.easyCerts" /> is
enabled, the helper script
<literal>nixos-kubernetes-node-join</literal> is available on PATH.
Given a token on stdin, it will copy the token to the kubernetes
secrets directory and restart the certmgr service. As requested
certificates are issued, the script will restart kubernetes cluster
components as needed for them to pick up new keypairs.
</para>
<note>
<para>
Multi-master (HA) clusters are not supported by the easyCerts
module.
</para>
</note>
<para>
In order to interact with an RBAC-enabled cluster as an
administrator, one needs to have cluster-admin privileges. By
default, when easyCerts is enabled, a cluster-admin kubeconfig file
is generated and linked into
<literal>/etc/kubernetes/cluster-admin.kubeconfig</literal> as
determined by
<xref linkend="opt-services.kubernetes.pki.etcClusterAdminKubeconfig" />.
<literal>export KUBECONFIG=/etc/kubernetes/cluster-admin.kubeconfig</literal>
will make kubectl use this kubeconfig to access and authenticate the
cluster. The cluster-admin kubeconfig references an auto-generated
keypair owned by root. Thus, only root on the kubernetes master may
obtain cluster-admin rights by means of this file.
</para>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-kernel-config">
<title>Linux Kernel</title>
<para>
You can override the Linux kernel and associated packages using the
option <literal>boot.kernelPackages</literal>. For instance, this
selects the Linux 3.10 kernel:
</para>
<programlisting language="bash">
boot.kernelPackages = pkgs.linuxPackages_3_10;
</programlisting>
<para>
Note that this not only replaces the kernel, but also packages that
are specific to the kernel version, such as the NVIDIA video
drivers. This ensures that driver packages are consistent with the
kernel.
</para>
<para>
The default Linux kernel configuration should be fine for most
users. You can see the configuration of your current kernel with the
following command:
</para>
<programlisting>
zcat /proc/config.gz
</programlisting>
<para>
If you want to change the kernel configuration, you can use the
<literal>packageOverrides</literal> feature (see
<xref linkend="sec-customising-packages" />). For instance, to
enable support for the kernel debugger KGDB:
</para>
<programlisting language="bash">
nixpkgs.config.packageOverrides = pkgs:
{ linux_3_4 = pkgs.linux_3_4.override {
extraConfig =
''
KGDB y
'';
};
};
</programlisting>
<para>
<literal>extraConfig</literal> takes a list of Linux kernel
configuration options, one per line. The name of the option should
not include the prefix <literal>CONFIG_</literal>. The option value
is typically <literal>y</literal>, <literal>n</literal> or
<literal>m</literal> (to build something as a kernel module).
</para>
<para>
Kernel modules for hardware devices are generally loaded
automatically by <literal>udev</literal>. You can force a module to
be loaded via <xref linkend="opt-boot.kernelModules" />, e.g.
</para>
<programlisting language="bash">
boot.kernelModules = [ &quot;fuse&quot; &quot;kvm-intel&quot; &quot;coretemp&quot; ];
</programlisting>
<para>
If the module is required early during the boot (e.g. to mount the
root file system), you can use
<xref linkend="opt-boot.initrd.kernelModules" />:
</para>
<programlisting language="bash">
boot.initrd.kernelModules = [ &quot;cifs&quot; ];
</programlisting>
<para>
This causes the specified modules and their dependencies to be added
to the initial ramdisk.
</para>
<para>
Kernel runtime parameters can be set through
<xref linkend="opt-boot.kernel.sysctl" />, e.g.
</para>
<programlisting language="bash">
boot.kernel.sysctl.&quot;net.ipv4.tcp_keepalive_time&quot; = 120;
</programlisting>
<para>
sets the kernels TCP keepalive time to 120 seconds. To see the
available parameters, run <literal>sysctl -a</literal>.
</para>
<section xml:id="sec-linux-config-customizing">
<title>Customize your kernel</title>
<para>
The first step before compiling the kernel is to generate an
appropriate <literal>.config</literal> configuration. Either you
pass your own config via the <literal>configfile</literal> setting
of <literal>linuxManualConfig</literal>:
</para>
<programlisting language="bash">
custom-kernel = super.linuxManualConfig {
inherit (super) stdenv hostPlatform;
inherit (linux_4_9) src;
version = &quot;${linux_4_9.version}-custom&quot;;
configfile = /home/me/my_kernel_config;
allowImportFromDerivation = true;
};
</programlisting>
<para>
You can edit the config with this snippet (by default
<literal>make menuconfig</literal> won't work out of the box on
nixos):
</para>
<programlisting>
nix-shell -E 'with import &lt;nixpkgs&gt; {}; kernelToOverride.overrideAttrs (o: {nativeBuildInputs=o.nativeBuildInputs ++ [ pkg-config ncurses ];})'
</programlisting>
<para>
or you can let nixpkgs generate the configuration. Nixpkgs
generates it via answering the interactive kernel utility
<literal>make config</literal>. The answers depend on parameters
passed to
<literal>pkgs/os-specific/linux/kernel/generic.nix</literal>
(which you can influence by overriding
<literal>extraConfig, autoModules, modDirVersion, preferBuiltin, extraConfig</literal>).
</para>
<programlisting language="bash">
mptcp93.override ({
name=&quot;mptcp-local&quot;;
ignoreConfigErrors = true;
autoModules = false;
kernelPreferBuiltin = true;
enableParallelBuilding = true;
extraConfig = ''
DEBUG_KERNEL y
FRAME_POINTER y
KGDB y
KGDB_SERIAL_CONSOLE y
DEBUG_INFO y
'';
});
</programlisting>
</section>
<section xml:id="sec-linux-config-developing-modules">
<title>Developing kernel modules</title>
<para>
When developing kernel modules it's often convenient to run
edit-compile-run loop as quickly as possible. See below snippet as
an example of developing <literal>mellanox</literal> drivers.
</para>
<programlisting>
$ nix-build '&lt;nixpkgs&gt;' -A linuxPackages.kernel.dev
$ nix-shell '&lt;nixpkgs&gt;' -A linuxPackages.kernel
$ unpackPhase
$ cd linux-*
$ make -C $dev/lib/modules/*/build M=$(pwd)/drivers/net/ethernet/mellanox modules
# insmod ./drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko
</programlisting>
</section>
</chapter>

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@ -51,8 +51,8 @@ SHA256:yjxl3UbTn31fLWeyLYTAKYJPRmzknjQZoyG8gSNEoIE my-user@workstation
</para>
<para>
The file system can be configured in NixOS via the usual
<link xlink:href="options.html#opt-fileSystems">fileSystems</link>
option. Heres a typical setup:
<link linkend="opt-fileSystems">fileSystems</link> option. Heres
a typical setup:
</para>
<programlisting language="bash">
{

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="module-services-subversion">
<title>Subversion</title>
<para>
<link xlink:href="https://subversion.apache.org/">Subversion</link>
is a centralized version-control system. It can use a
<link xlink:href="http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.choosing">variety
of protocols</link> for communication between client and server.
</para>
<section xml:id="module-services-subversion-apache-httpd">
<title>Subversion inside Apache HTTP</title>
<para>
This section focuses on configuring a web-based server on top of
the Apache HTTP server, which uses
<link xlink:href="http://www.webdav.org/">WebDAV</link>/<link xlink:href="http://www.webdav.org/deltav/WWW10/deltav-intro.htm">DeltaV</link>
for communication.
</para>
<para>
For more information on the general setup, please refer to the
<link xlink:href="http://svnbook.red-bean.com/en/1.7/svn-book.html#svn.serverconfig.httpd">the
appropriate section of the Subversion book</link>.
</para>
<para>
To configure, include in
<literal>/etc/nixos/configuration.nix</literal> code to activate
Apache HTTP, setting
<xref linkend="opt-services.httpd.adminAddr" /> appropriately:
</para>
<programlisting language="bash">
services.httpd.enable = true;
services.httpd.adminAddr = ...;
networking.firewall.allowedTCPPorts = [ 80 443 ];
</programlisting>
<para>
For a simple Subversion server with basic authentication,
configure the Subversion module for Apache as follows, setting
<literal>hostName</literal> and <literal>documentRoot</literal>
appropriately, and <literal>SVNParentPath</literal> to the parent
directory of the repositories,
<literal>AuthzSVNAccessFile</literal> to the location of the
<literal>.authz</literal> file describing access permission, and
<literal>AuthUserFile</literal> to the password file.
</para>
<programlisting language="bash">
services.httpd.extraModules = [
# note that order is *super* important here
{ name = &quot;dav_svn&quot;; path = &quot;${pkgs.apacheHttpdPackages.subversion}/modules/mod_dav_svn.so&quot;; }
{ name = &quot;authz_svn&quot;; path = &quot;${pkgs.apacheHttpdPackages.subversion}/modules/mod_authz_svn.so&quot;; }
];
services.httpd.virtualHosts = {
&quot;svn&quot; = {
hostName = HOSTNAME;
documentRoot = DOCUMENTROOT;
locations.&quot;/svn&quot;.extraConfig = ''
DAV svn
SVNParentPath REPO_PARENT
AuthzSVNAccessFile ACCESS_FILE
AuthName &quot;SVN Repositories&quot;
AuthType Basic
AuthUserFile PASSWORD_FILE
Require valid-user
'';
}
</programlisting>
<para>
The key <literal>&quot;svn&quot;</literal> is just a symbolic name
identifying the virtual host. The
<literal>&quot;/svn&quot;</literal> in
<literal>locations.&quot;/svn&quot;.extraConfig</literal> is the
path underneath which the repositories will be served.
</para>
<para>
<link xlink:href="https://wiki.archlinux.org/index.php/Subversion">This
page</link> explains how to set up the Subversion configuration
itself. This boils down to the following:
</para>
<para>
Underneath <literal>REPO_PARENT</literal> repositories can be set
up as follows:
</para>
<programlisting>
$ svn create REPO_NAME
</programlisting>
<para>
Repository files need to be accessible by
<literal>wwwrun</literal>:
</para>
<programlisting>
$ chown -R wwwrun:wwwrun REPO_PARENT
</programlisting>
<para>
The password file <literal>PASSWORD_FILE</literal> can be created
as follows:
</para>
<programlisting>
$ htpasswd -cs PASSWORD_FILE USER_NAME
</programlisting>
<para>
Additional users can be set up similarly, omitting the
<literal>c</literal> flag:
</para>
<programlisting>
$ htpasswd -s PASSWORD_FILE USER_NAME
</programlisting>
<para>
The file describing access permissions
<literal>ACCESS_FILE</literal> will look something like the
following:
</para>
<programlisting language="bash">
[/]
* = r
[REPO_NAME:/]
USER_NAME = rw
</programlisting>
<para>
The Subversion repositories will be accessible as
<literal>http://HOSTNAME/svn/REPO_NAME</literal>.
</para>
</section>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-user-management">
<title>User Management</title>
<para>
NixOS supports both declarative and imperative styles of user
management. In the declarative style, users are specified in
<literal>configuration.nix</literal>. For instance, the following
states that a user account named <literal>alice</literal> shall
exist:
</para>
<programlisting language="bash">
users.users.alice = {
isNormalUser = true;
home = &quot;/home/alice&quot;;
description = &quot;Alice Foobar&quot;;
extraGroups = [ &quot;wheel&quot; &quot;networkmanager&quot; ];
openssh.authorizedKeys.keys = [ &quot;ssh-dss AAAAB3Nza... alice@foobar&quot; ];
};
</programlisting>
<para>
Note that <literal>alice</literal> is a member of the
<literal>wheel</literal> and <literal>networkmanager</literal>
groups, which allows her to use <literal>sudo</literal> to execute
commands as <literal>root</literal> and to configure the network,
respectively. Also note the SSH public key that allows remote logins
with the corresponding private key. Users created in this way do not
have a password by default, so they cannot log in via mechanisms
that require a password. However, you can use the
<literal>passwd</literal> program to set a password, which is
retained across invocations of <literal>nixos-rebuild</literal>.
</para>
<para>
If you set <xref linkend="opt-users.mutableUsers" /> to false, then
the contents of <literal>/etc/passwd</literal> and
<literal>/etc/group</literal> will be congruent to your NixOS
configuration. For instance, if you remove a user from
<xref linkend="opt-users.users" /> and run nixos-rebuild, the user
account will cease to exist. Also, imperative commands for managing
users and groups, such as useradd, are no longer available.
Passwords may still be assigned by setting the user's
<link linkend="opt-users.users._name_.hashedPassword">hashedPassword</link>
option. A hashed password can be generated using
<literal>mkpasswd -m sha-512</literal>.
</para>
<para>
A user ID (uid) is assigned automatically. You can also specify a
uid manually by adding
</para>
<programlisting language="bash">
uid = 1000;
</programlisting>
<para>
to the user specification.
</para>
<para>
Groups can be specified similarly. The following states that a group
named <literal>students</literal> shall exist:
</para>
<programlisting language="bash">
users.groups.students.gid = 1000;
</programlisting>
<para>
As with users, the group ID (gid) is optional and will be assigned
automatically if its missing.
</para>
<para>
In the imperative style, users and groups are managed by commands
such as <literal>useradd</literal>, <literal>groupmod</literal> and
so on. For instance, to create a user account named
<literal>alice</literal>:
</para>
<programlisting>
# useradd -m alice
</programlisting>
<para>
To make all nix tools available to this new user use `su - USER`
which opens a login shell (==shell that loads the profile) for given
user. This will create the ~/.nix-defexpr symlink. So run:
</para>
<programlisting>
# su - alice -c &quot;true&quot;
</programlisting>
<para>
The flag <literal>-m</literal> causes the creation of a home
directory for the new user, which is generally what you want. The
user does not have an initial password and therefore cannot log in.
A password can be set using the <literal>passwd</literal> utility:
</para>
<programlisting>
# passwd alice
Enter new UNIX password: ***
Retype new UNIX password: ***
</programlisting>
<para>
A user can be deleted using <literal>userdel</literal>:
</para>
<programlisting>
# userdel -r alice
</programlisting>
<para>
The flag <literal>-r</literal> deletes the users home directory.
Accounts can be modified using <literal>usermod</literal>. Unix
groups can be managed using <literal>groupadd</literal>,
<literal>groupmod</literal> and <literal>groupdel</literal>.
</para>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-wayland">
<title>Wayland</title>
<para>
While X11 (see <xref linkend="sec-x11" />) is still the primary
display technology on NixOS, Wayland support is steadily improving.
Where X11 separates the X Server and the window manager, on Wayland
those are combined: a Wayland Compositor is like an X11 window
manager, but also embeds the Wayland 'Server' functionality. This
means it is sufficient to install a Wayland Compositor such as sway
without separately enabling a Wayland server:
</para>
<programlisting language="bash">
programs.sway.enable = true;
</programlisting>
<para>
This installs the sway compositor along with some essential
utilities. Now you can start sway from the TTY console.
</para>
<para>
If you are using a wlroots-based compositor, like sway, and want to
be able to share your screen, you might want to activate this
option:
</para>
<programlisting language="bash">
xdg.portal.wlr.enable = true;
</programlisting>
<para>
and configure Pipewire using
<xref linkend="opt-services.pipewire.enable" /> and related options.
</para>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-x11">
<title>X Window System</title>
<para>
The X Window System (X11) provides the basis of NixOS graphical
user interface. It can be enabled as follows:
</para>
<programlisting language="bash">
services.xserver.enable = true;
</programlisting>
<para>
The X server will automatically detect and use the appropriate video
driver from a set of X.org drivers (such as <literal>vesa</literal>
and <literal>intel</literal>). You can also specify a driver
manually, e.g.
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;r128&quot; ];
</programlisting>
<para>
to enable X.orgs <literal>xf86-video-r128</literal> driver.
</para>
<para>
You also need to enable at least one desktop or window manager.
Otherwise, you can only log into a plain undecorated
<literal>xterm</literal> window. Thus you should pick one or more of
the following lines:
</para>
<programlisting language="bash">
services.xserver.desktopManager.plasma5.enable = true;
services.xserver.desktopManager.xfce.enable = true;
services.xserver.desktopManager.gnome.enable = true;
services.xserver.desktopManager.mate.enable = true;
services.xserver.windowManager.xmonad.enable = true;
services.xserver.windowManager.twm.enable = true;
services.xserver.windowManager.icewm.enable = true;
services.xserver.windowManager.i3.enable = true;
services.xserver.windowManager.herbstluftwm.enable = true;
</programlisting>
<para>
NixOSs default <emphasis>display manager</emphasis> (the program
that provides a graphical login prompt and manages the X server) is
LightDM. You can select an alternative one by picking one of the
following lines:
</para>
<programlisting language="bash">
services.xserver.displayManager.sddm.enable = true;
services.xserver.displayManager.gdm.enable = true;
</programlisting>
<para>
You can set the keyboard layout (and optionally the layout variant):
</para>
<programlisting language="bash">
services.xserver.layout = &quot;de&quot;;
services.xserver.xkbVariant = &quot;neo&quot;;
</programlisting>
<para>
The X server is started automatically at boot time. If you dont
want this to happen, you can set:
</para>
<programlisting language="bash">
services.xserver.autorun = false;
</programlisting>
<para>
The X server can then be started manually:
</para>
<programlisting>
# systemctl start display-manager.service
</programlisting>
<para>
On 64-bit systems, if you want OpenGL for 32-bit programs such as in
Wine, you should also set the following:
</para>
<programlisting language="bash">
hardware.opengl.driSupport32Bit = true;
</programlisting>
<section xml:id="sec-x11-auto-login">
<title>Auto-login</title>
<para>
The x11 login screen can be skipped entirely, automatically
logging you into your window manager and desktop environment when
you boot your computer.
</para>
<para>
This is especially helpful if you have disk encryption enabled.
Since you already have to provide a password to decrypt your disk,
entering a second password to login can be redundant.
</para>
<para>
To enable auto-login, you need to define your default window
manager and desktop environment. If you wanted no desktop
environment and i3 as your your window manager, you'd define:
</para>
<programlisting language="bash">
services.xserver.displayManager.defaultSession = &quot;none+i3&quot;;
</programlisting>
<para>
Every display manager in NixOS supports auto-login, here is an
example using lightdm for a user <literal>alice</literal>:
</para>
<programlisting language="bash">
services.xserver.displayManager.lightdm.enable = true;
services.xserver.displayManager.autoLogin.enable = true;
services.xserver.displayManager.autoLogin.user = &quot;alice&quot;;
</programlisting>
</section>
<section xml:id="sec-x11--graphics-cards-intel">
<title>Intel Graphics drivers</title>
<para>
There are two choices for Intel Graphics drivers in X.org:
<literal>modesetting</literal> (included in the xorg-server
itself) and <literal>intel</literal> (provided by the package
xf86-video-intel).
</para>
<para>
The default and recommended is <literal>modesetting</literal>. It
is a generic driver which uses the kernel
<link xlink:href="https://en.wikipedia.org/wiki/Mode_setting">mode
setting</link> (KMS) mechanism. It supports Glamor (2D graphics
acceleration via OpenGL) and is actively maintained but may
perform worse in some cases (like in old chipsets).
</para>
<para>
The second driver, <literal>intel</literal>, is specific to Intel
GPUs, but not recommended by most distributions: it lacks several
modern features (for example, it doesn't support Glamor) and the
package hasn't been officially updated since 2015.
</para>
<para>
The results vary depending on the hardware, so you may have to try
both drivers. Use the option
<xref linkend="opt-services.xserver.videoDrivers" /> to set one.
The recommended configuration for modern systems is:
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;modesetting&quot; ];
services.xserver.useGlamor = true;
</programlisting>
<para>
If you experience screen tearing no matter what, this
configuration was reported to resolve the issue:
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;intel&quot; ];
services.xserver.deviceSection = ''
Option &quot;DRI&quot; &quot;2&quot;
Option &quot;TearFree&quot; &quot;true&quot;
'';
</programlisting>
<para>
Note that this will likely downgrade the performance compared to
<literal>modesetting</literal> or <literal>intel</literal> with
DRI 3 (default).
</para>
</section>
<section xml:id="sec-x11-graphics-cards-nvidia">
<title>Proprietary NVIDIA drivers</title>
<para>
NVIDIA provides a proprietary driver for its graphics cards that
has better 3D performance than the X.org drivers. It is not
enabled by default because its not free software. You can enable
it as follows:
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;nvidia&quot; ];
</programlisting>
<para>
Or if you have an older card, you may have to use one of the
legacy drivers:
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;nvidiaLegacy390&quot; ];
services.xserver.videoDrivers = [ &quot;nvidiaLegacy340&quot; ];
services.xserver.videoDrivers = [ &quot;nvidiaLegacy304&quot; ];
</programlisting>
<para>
You may need to reboot after enabling this driver to prevent a
clash with other kernel modules.
</para>
</section>
<section xml:id="sec-x11--graphics-cards-amd">
<title>Proprietary AMD drivers</title>
<para>
AMD provides a proprietary driver for its graphics cards that is
not enabled by default because its not Free Software, is often
broken in nixpkgs and as of this writing doesn't offer more
features or performance. If you still want to use it anyway, you
need to explicitly set:
</para>
<programlisting language="bash">
services.xserver.videoDrivers = [ &quot;amdgpu-pro&quot; ];
</programlisting>
<para>
You will need to reboot after enabling this driver to prevent a
clash with other kernel modules.
</para>
</section>
<section xml:id="sec-x11-touchpads">
<title>Touchpads</title>
<para>
Support for Synaptics touchpads (found in many laptops such as the
Dell Latitude series) can be enabled as follows:
</para>
<programlisting language="bash">
services.xserver.libinput.enable = true;
</programlisting>
<para>
The driver has many options (see <xref linkend="ch-options" />).
For instance, the following disables tap-to-click behavior:
</para>
<programlisting language="bash">
services.xserver.libinput.touchpad.tapping = false;
</programlisting>
<para>
Note: the use of <literal>services.xserver.synaptics</literal> is
deprecated since NixOS 17.09.
</para>
</section>
<section xml:id="sec-x11-gtk-and-qt-themes">
<title>GTK/Qt themes</title>
<para>
GTK themes can be installed either to user profile or system-wide
(via <literal>environment.systemPackages</literal>). To make Qt 5
applications look similar to GTK ones, you can use the following
configuration:
</para>
<programlisting language="bash">
qt5.enable = true;
qt5.platformTheme = &quot;gtk2&quot;;
qt5.style = &quot;gtk2&quot;;
</programlisting>
</section>
<section xml:id="custom-xkb-layouts">
<title>Custom XKB layouts</title>
<para>
It is possible to install custom
<link xlink:href="https://en.wikipedia.org/wiki/X_keyboard_extension">
XKB </link> keyboard layouts using the option
<literal>services.xserver.extraLayouts</literal>.
</para>
<para>
As a first example, we are going to create a layout based on the
basic US layout, with an additional layer to type some greek
symbols by pressing the right-alt key.
</para>
<para>
Create a file called <literal>us-greek</literal> with the
following content (under a directory called
<literal>symbols</literal>; it's an XKB peculiarity that will help
with testing):
</para>
<programlisting language="bash">
xkb_symbols &quot;us-greek&quot;
{
include &quot;us(basic)&quot; // includes the base US keys
include &quot;level3(ralt_switch)&quot; // configures right alt as a third level switch
key &lt;LatA&gt; { [ a, A, Greek_alpha ] };
key &lt;LatB&gt; { [ b, B, Greek_beta ] };
key &lt;LatG&gt; { [ g, G, Greek_gamma ] };
key &lt;LatD&gt; { [ d, D, Greek_delta ] };
key &lt;LatZ&gt; { [ z, Z, Greek_zeta ] };
};
</programlisting>
<para>
A minimal layout specification must include the following:
</para>
<programlisting language="bash">
services.xserver.extraLayouts.us-greek = {
description = &quot;US layout with alt-gr greek&quot;;
languages = [ &quot;eng&quot; ];
symbolsFile = /yourpath/symbols/us-greek;
};
</programlisting>
<note>
<para>
The name (after <literal>extraLayouts.</literal>) should match
the one given to the <literal>xkb_symbols</literal> block.
</para>
</note>
<para>
Applying this customization requires rebuilding several packages,
and a broken XKB file can lead to the X session crashing at login.
Therefore, you're strongly advised to <emphasis role="strong">test
your layout before applying it</emphasis>:
</para>
<programlisting>
$ nix-shell -p xorg.xkbcomp
$ setxkbmap -I/yourpath us-greek -print | xkbcomp -I/yourpath - $DISPLAY
</programlisting>
<para>
You can inspect the predefined XKB files for examples:
</para>
<programlisting>
$ echo &quot;$(nix-build --no-out-link '&lt;nixpkgs&gt;' -A xorg.xkeyboardconfig)/etc/X11/xkb/&quot;
</programlisting>
<para>
Once the configuration is applied, and you did a logout/login
cycle, the layout should be ready to use. You can try it by e.g.
running <literal>setxkbmap us-greek</literal> and then type
<literal>&lt;alt&gt;+a</literal> (it may not get applied in your
terminal straight away). To change the default, the usual
<literal>services.xserver.layout</literal> option can still be
used.
</para>
<para>
A layout can have several other components besides
<literal>xkb_symbols</literal>, for example we will define new
keycodes for some multimedia key and bind these to some symbol.
</para>
<para>
Use the <emphasis>xev</emphasis> utility from
<literal>pkgs.xorg.xev</literal> to find the codes of the keys of
interest, then create a <literal>media-key</literal> file to hold
the keycodes definitions
</para>
<programlisting language="bash">
xkb_keycodes &quot;media&quot;
{
&lt;volUp&gt; = 123;
&lt;volDown&gt; = 456;
}
</programlisting>
<para>
Now use the newly define keycodes in <literal>media-sym</literal>:
</para>
<programlisting language="bash">
xkb_symbols &quot;media&quot;
{
key.type = &quot;ONE_LEVEL&quot;;
key &lt;volUp&gt; { [ XF86AudioLowerVolume ] };
key &lt;volDown&gt; { [ XF86AudioRaiseVolume ] };
}
</programlisting>
<para>
As before, to install the layout do
</para>
<programlisting language="bash">
services.xserver.extraLayouts.media = {
description = &quot;Multimedia keys remapping&quot;;
languages = [ &quot;eng&quot; ];
symbolsFile = /path/to/media-key;
keycodesFile = /path/to/media-sym;
};
</programlisting>
<note>
<para>
The function
<literal>pkgs.writeText &lt;filename&gt; &lt;content&gt;</literal>
can be useful if you prefer to keep the layout definitions
inside the NixOS configuration.
</para>
</note>
<para>
Unfortunately, the Xorg server does not (currently) support
setting a keymap directly but relies instead on XKB rules to
select the matching components (keycodes, types, ...) of a layout.
This means that components other than symbols won't be loaded by
default. As a workaround, you can set the keymap using
<literal>setxkbmap</literal> at the start of the session with:
</para>
<programlisting language="bash">
services.xserver.displayManager.sessionCommands = &quot;setxkbmap -keycodes media&quot;;
</programlisting>
<para>
If you are manually starting the X server, you should set the
argument <literal>-xkbdir /etc/X11/xkb</literal>, otherwise X
won't find your layout files. For example with
<literal>xinit</literal> run
</para>
<programlisting>
$ xinit -- -xkbdir /etc/X11/xkb
</programlisting>
<para>
To learn how to write layouts take a look at the XKB
<link xlink:href="https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts">documentation
</link>. More example layouts can also be found
<link xlink:href="https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples">here
</link>.
</para>
</section>
</chapter>

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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-xfce">
<title>Xfce Desktop Environment</title>
<para>
To enable the Xfce Desktop Environment, set
</para>
<programlisting language="bash">
services.xserver.desktopManager.xfce.enable = true;
services.xserver.displayManager.defaultSession = &quot;xfce&quot;;
</programlisting>
<para>
Optionally, <emphasis>picom</emphasis> can be enabled for nice
graphical effects, some example settings:
</para>
<programlisting language="bash">
services.picom = {
enable = true;
fade = true;
inactiveOpacity = 0.9;
shadow = true;
fadeDelta = 4;
};
</programlisting>
<para>
Some Xfce programs are not installed automatically. To install them
manually (system wide), put them into your
<xref linkend="opt-environment.systemPackages" /> from
<literal>pkgs.xfce</literal>.
</para>
<section xml:id="sec-xfce-thunar-plugins">
<title>Thunar Plugins</title>
<para>
If you'd like to add extra plugins to Thunar, add them to
<xref linkend="opt-services.xserver.desktopManager.xfce.thunarPlugins" />.
You shouldn't just add them to
<xref linkend="opt-environment.systemPackages" />.
</para>
</section>
<section xml:id="sec-xfce-troubleshooting">
<title>Troubleshooting</title>
<para>
Even after enabling udisks2, volume management might not work.
Thunar and/or the desktop takes time to show up. Thunar will spit
out this kind of message on start (look at
<literal>journalctl --user -b</literal>).
</para>
<programlisting>
Thunar:2410): GVFS-RemoteVolumeMonitor-WARNING **: remote volume monitor with dbus name org.gtk.Private.UDisks2VolumeMonitor is not supported
</programlisting>
<para>
This is caused by some needed GNOME services not running. This is
all fixed by enabling &quot;Launch GNOME services on startup&quot;
in the Advanced tab of the Session and Startup settings panel.
Alternatively, you can run this command to do the same thing.
</para>
<programlisting>
$ xfconf-query -c xfce4-session -p /compat/LaunchGNOME -s true
</programlisting>
<para>
A log-out and re-log will be needed for this to take effect.
</para>
</section>
</chapter>