494 lines
16 KiB
XML
494 lines
16 KiB
XML
<refentry xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude">
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<refmeta>
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<refentrytitle><command>nixos-rebuild</command>
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</refentrytitle><manvolnum>8</manvolnum>
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<refmiscinfo class="source">NixOS</refmiscinfo>
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<!-- <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> -->
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</refmeta>
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<refnamediv>
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<refname><command>nixos-rebuild</command>
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</refname><refpurpose>reconfigure a NixOS machine</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>nixos-rebuild</command><group choice='req'>
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<arg choice='plain'>
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<option>switch</option>
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</arg>
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<arg choice='plain'>
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<option>boot</option>
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</arg>
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<arg choice='plain'>
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<option>test</option>
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</arg>
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<arg choice='plain'>
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<option>build</option>
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</arg>
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<arg choice='plain'>
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<option>dry-build</option>
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</arg>
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<arg choice='plain'>
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<option>dry-activate</option>
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</arg>
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<arg choice='plain'>
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<option>build-vm</option>
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</arg>
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<arg choice='plain'>
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<option>build-vm-with-bootloader</option>
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</arg>
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</group>
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<sbr />
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<arg>
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<option>--upgrade</option>
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</arg>
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<arg>
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<option>--install-bootloader</option>
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</arg>
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<arg>
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<option>--no-build-nix</option>
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</arg>
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<arg>
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<option>--fast</option>
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</arg>
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<arg>
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<option>--rollback</option>
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</arg>
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<arg>
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<option>--builders</option>
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<replaceable>builder-spec</replaceable>
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</arg>
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<sbr />
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<arg>
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<group choice='req'>
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<arg choice='plain'>
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<option>--profile-name</option>
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</arg>
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<arg choice='plain'>
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<option>-p</option>
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</arg>
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</group> <replaceable>name</replaceable>
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</arg>
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<sbr />
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<arg>
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<option>--show-trace</option>
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</arg>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsection>
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<title>Description</title>
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<para>
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This command updates the system so that it corresponds to the configuration
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specified in <filename>/etc/nixos/configuration.nix</filename>. Thus, every
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time you modify <filename>/etc/nixos/configuration.nix</filename> or any
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NixOS module, you must run <command>nixos-rebuild</command> to make the
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changes take effect. It builds the new system in
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<filename>/nix/store</filename>, runs its activation script, and stop and
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(re)starts any system services if needed.
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</para>
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<para>
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This command has one required argument, which specifies the desired
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operation. It must be one of the following:
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<variablelist>
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<varlistentry>
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<term>
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<option>switch</option>
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</term>
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<listitem>
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<para>
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Build and activate the new configuration, and make it the boot default.
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That is, the configuration is added to the GRUB boot menu as the default
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menu entry, so that subsequent reboots will boot the system into the new
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configuration. Previous configurations activated with
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<command>nixos-rebuild switch</command> or <command>nixos-rebuild
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boot</command> remain available in the GRUB menu.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>boot</option>
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</term>
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<listitem>
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<para>
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Build the new configuration and make it the boot default (as with
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<command>nixos-rebuild switch</command>), but do not activate it. That
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is, the system continues to run the previous configuration until the
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next reboot.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>test</option>
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</term>
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<listitem>
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<para>
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Build and activate the new configuration, but do not add it to the GRUB
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boot menu. Thus, if you reboot the system (or if it crashes), you will
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automatically revert to the default configuration (i.e. the
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configuration resulting from the last call to <command>nixos-rebuild
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switch</command> or <command>nixos-rebuild boot</command>).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>build</option>
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</term>
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<listitem>
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<para>
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Build the new configuration, but neither activate it nor add it to the
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GRUB boot menu. It leaves a symlink named <filename>result</filename> in
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the current directory, which points to the output of the top-level
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“system” derivation. This is essentially the same as doing
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<screen>
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$ nix-build /path/to/nixpkgs/nixos -A system
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</screen>
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Note that you do not need to be <literal>root</literal> to run
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<command>nixos-rebuild build</command>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>dry-build</option>
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</term>
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<listitem>
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<para>
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Show what store paths would be built or downloaded by any of the
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operations above, but otherwise do nothing.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>dry-activate</option>
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</term>
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<listitem>
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<para>
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Build the new configuration, but instead of activating it, show what
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changes would be performed by the activation (i.e. by
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<command>nixos-rebuild test</command>). For instance, this command will
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print which systemd units would be restarted. The list of changes is not
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guaranteed to be complete.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>build-vm</option>
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</term>
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<listitem>
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<para>
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Build a script that starts a NixOS virtual machine with the desired
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configuration. It leaves a symlink <filename>result</filename> in the
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current directory that points (under
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<filename>result/bin/run-<replaceable>hostname</replaceable>-vm</filename>)
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at the script that starts the VM. Thus, to test a NixOS configuration in
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a virtual machine, you should do the following:
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<screen>
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$ nixos-rebuild build-vm
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$ ./result/bin/run-*-vm
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</screen>
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</para>
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<para>
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The VM is implemented using the <literal>qemu</literal> package. For
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best performance, you should load the <literal>kvm-intel</literal> or
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<literal>kvm-amd</literal> kernel modules to get hardware
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virtualisation.
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</para>
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<para>
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The VM mounts the Nix store of the host through the 9P file system. The
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host Nix store is read-only, so Nix commands that modify the Nix store
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will not work in the VM. This includes commands such as
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<command>nixos-rebuild</command>; to change the VM’s configuration,
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you must halt the VM and re-run the commands above.
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</para>
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<para>
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The VM has its own <literal>ext3</literal> root file system, which is
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automatically created when the VM is first started, and is persistent
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across reboots of the VM. It is stored in
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<literal>./<replaceable>hostname</replaceable>.qcow2</literal>.
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<!-- The entire file system hierarchy of the host is available in
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the VM under <filename>/hostfs</filename>.-->
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>build-vm-with-bootloader</option>
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</term>
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<listitem>
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<para>
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Like <option>build-vm</option>, but boots using the regular boot loader
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of your configuration (e.g., GRUB 1 or 2), rather than booting directly
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into the kernel and initial ramdisk of the system. This allows you to
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test whether the boot loader works correctly. However, it does not
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guarantee that your NixOS configuration will boot successfully on the
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host hardware (i.e., after running <command>nixos-rebuild
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switch</command>), because the hardware and boot loader configuration in
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the VM are different. The boot loader is installed on an automatically
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generated virtual disk containing a <filename>/boot</filename>
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partition, which is mounted read-only in the VM.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsection>
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<refsection>
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<title>Options</title>
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<para>
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This command accepts the following options:
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<option>--upgrade</option>
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</term>
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<listitem>
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<para>
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Fetch the latest version of NixOS from the NixOS channel.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--install-bootloader</option>
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</term>
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<listitem>
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<para>
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Causes the boot loader to be (re)installed on the device specified by the
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relevant configuration options.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--no-build-nix</option>
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</term>
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<listitem>
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<para>
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Normally, <command>nixos-rebuild</command> first builds the
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<varname>nixUnstable</varname> attribute in Nixpkgs, and uses the
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resulting instance of the Nix package manager to build the new system
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configuration. This is necessary if the NixOS modules use features not
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provided by the currently installed version of Nix. This option disables
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building a new Nix.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--fast</option>
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</term>
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<listitem>
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<para>
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Equivalent to <option>--no-build-nix</option>
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<option>--show-trace</option>. This option is useful if you call
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<command>nixos-rebuild</command> frequently (e.g. if you’re hacking on
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a NixOS module).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--rollback</option>
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</term>
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<listitem>
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<para>
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Instead of building a new configuration as specified by
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<filename>/etc/nixos/configuration.nix</filename>, roll back to the
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previous configuration. (The previous configuration is defined as the one
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before the “current” generation of the Nix profile
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<filename>/nix/var/nix/profiles/system</filename>.)
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--builders</option>
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<replaceable>builder-spec</replaceable>
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</term>
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<listitem>
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<para>
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Allow ad-hoc remote builders for building the new system.
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This requires the user executing <command>nixos-rebuild</command> (usually
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root) to be configured as a trusted user in the Nix daemon. This can be
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achieved by using the <literal>nix.trustedUsers</literal> NixOS option.
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Examples values for that option are described in the
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<literal>Remote builds chapter<literal> in the Nix manual,
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(i.e. <command>--builders "ssh://bigbrother x86_64-linux"</command>).
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By specifying an empty string existing builders specified in
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<filename>/etc/nix/machines</filename> can be ignored:
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<command>--builders ""</command> for example when they are not
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reachable due to network connectivity.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--profile-name</option>
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</term>
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<term>
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<option>-p</option>
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</term>
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<listitem>
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<para>
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Instead of using the Nix profile
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<filename>/nix/var/nix/profiles/system</filename> to keep track of the
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current and previous system configurations, use
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<filename>/nix/var/nix/profiles/system-profiles/<replaceable>name</replaceable></filename>.
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When you use GRUB 2, for every system profile created with this flag,
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NixOS will create a submenu named “NixOS - Profile
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'<replaceable>name</replaceable>'” in GRUB’s boot menu, containing
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the current and previous configurations of this profile.
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</para>
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<para>
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For instance, if you want to test a configuration file named
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<filename>test.nix</filename> without affecting the default system
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profile, you would do:
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<screen>
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$ nixos-rebuild switch -p test -I nixos-config=./test.nix
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</screen>
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The new configuration will appear in the GRUB 2 submenu “NixOS -
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Profile 'test'”.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--build-host</option>
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</term>
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<listitem>
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<para>
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Instead of building the new configuration locally, use the specified host
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to perform the build. The host needs to be accessible with ssh, and must
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be able to perform Nix builds. If the option
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<option>--target-host</option> is not set, the build will be copied back
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to the local machine when done.
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</para>
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<para>
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Note that, if <option>--no-build-nix</option> is not specified, Nix will
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be built both locally and remotely. This is because the configuration
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will always be evaluated locally even though the building might be
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performed remotely.
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</para>
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<para>
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You can include a remote user name in the host name
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(<replaceable>user@host</replaceable>). You can also set ssh options by
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defining the <envar>NIX_SSHOPTS</envar> environment variable.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<option>--target-host</option>
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</term>
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<listitem>
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<para>
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Specifies the NixOS target host. By setting this to something other than
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<replaceable>localhost</replaceable>, the system activation will happen
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on the remote host instead of the local machine. The remote host needs to
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be accessible over ssh, and for the commands <option>switch</option>,
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<option>boot</option> and <option>test</option> you need root access.
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</para>
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<para>
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If <option>--build-host</option> is not explicitly specified,
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<option>--build-host</option> will implicitly be set to the same value as
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<option>--target-host</option>. So, if you only specify
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<option>--target-host</option> both building and activation will take
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place remotely (and no build artifacts will be copied to the local
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machine).
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</para>
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<para>
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You can include a remote user name in the host name
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(<replaceable>user@host</replaceable>). You can also set ssh options by
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defining the <envar>NIX_SSHOPTS</envar> environment variable.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>
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In addition, <command>nixos-rebuild</command> accepts various Nix-related
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flags, including <option>--max-jobs</option> / <option>-j</option>,
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<option>--show-trace</option>, <option>--keep-failed</option>,
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<option>--keep-going</option> and <option>--verbose</option> /
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<option>-v</option>. See the Nix manual for details.
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</para>
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</refsection>
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<refsection>
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<title>Environment</title>
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<variablelist>
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<varlistentry>
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<term>
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<envar>NIXOS_CONFIG</envar>
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</term>
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<listitem>
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<para>
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Path to the main NixOS configuration module. Defaults to
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<filename>/etc/nixos/configuration.nix</filename>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<envar>NIX_SSHOPTS</envar>
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</term>
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<listitem>
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<para>
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Additional options to be passed to <command>ssh</command> on the command
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line.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection>
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<title>Files</title>
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<variablelist>
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<varlistentry>
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<term>
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<filename>/run/current-system</filename>
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</term>
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<listitem>
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<para>
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A symlink to the currently active system configuration in the Nix store.
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||
</para>
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</listitem>
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||
</varlistentry>
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<varlistentry>
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<term>
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<filename>/nix/var/nix/profiles/system</filename>
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</term>
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<listitem>
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||
<para>
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The Nix profile that contains the current and previous system
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configurations. Used to generate the GRUB boot menu.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection>
|
||
<title>Bugs</title>
|
||
<para>
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||
This command should be renamed to something more descriptive.
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</para>
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||
</refsection>
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||
</refentry>
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