According to Freenode's ##AWS, the metadata server can sometimes
take a few moments to get its shoes on, and the very first boot
of a machine can see failed requests for a few moments.
AWS's metadata service has two versions. Version 1 allowed plain HTTP
requests to get metadata. However, this was frequently abused when a
user could trick an AWS-hosted server in to proxying requests to the
metadata service. Since the metadata service is frequently used to
generate AWS access keys, this is pretty gnarly. Version two is
identical except it requires the caller to request a token and provide
it on each request.
Today, starting a NixOS AMI in EC2 where the metadata service is
configured to only allow v2 requests fails: the user's SSH key is not
placed, and configuration provided by the user-data is not applied.
The server is useless. This patch addresses that.
Note the dependency on curl is not a joyful one, and it expand the
initrd by 30M. However, see the added comment for more information
about why this is needed. Note the idea of using `echo` and `nc` are
laughable. Don't do that.
We currently build CONFIG_IPV6=m.
This seems to be not really well-supported in mainline kernels - see
https://lore.kernel.org/netdev/20201115224509.2020651-1-flokli@flokli.de/T/#u
Compiling it as a module doesn't give too much benefit - even for people
who did explicitly set `enableIPv6` to false, the `ipv6` module was
still loaded, as soon as another module was loaded that requires it
(bridge,br_netfilter,wireguard,ip6table_mangle,sctp,…).
By compiling it in, we only loose the possibility to not add it to
`boot.kernelModules` anymore (as it's part of the kernel directly). The
space savings are negligible.
People wanting to disable IPv6 still get the appropriate sysctls and
options set (while having the kernel code loaded), nothing is really
changing here.
This adds a `package` option to allow for easier overriding of the used
CodiMD version and `runCommandLocal` with `nativeBuildInputs` is now
used to pretty print the configuration.
This used to be done by udev, but that was removed in
systemd/systemd@6b2229c. The links are created by systemd at the end of
stage-2, but activation scripts might need them earlier.
This is to ensure that whenever we install the desktop item we also have
the script installed. Prior to b02719a we always had the reference to
the script in the desktop item. Since desktop items are being copied to
home directories and thus "bit rod" over time that absolute path was
removed.
Other units depend on nss-lookup.target and expect the DNS resolution to
work once that target is reached. The previous version
`wants=nss-lookup.target` made this unit require the nss-lookup.target
to be reached before this was started.
Another change that we can probalby do is drop the before relationship
with the nss-lookup.target. That might just be implied with the current
version.
This option allows users to specify a local UNIX control socket to
"remote control" the daemon. System users, that should be permitted to
access the daemon, must be in the `unbound` group in order to access the
socket. When a socket path is configured we are also creating the
required group.
Currently this only supports the UNIX socket mode while unbound actually
supports more advanced types. Users are still able to configure more
complex scenarios via the `extraConfig` attribute.
When this option is set to `null` (the default) it doesn't affect the
system configuration at all. The unbound defaults for control sockets
apply and no additional groups are created.
Previously we just applied a very minimal set of restrictions and
trusted unbound to properly drop root privs and capabilities.
With this change I am (for the most part) just using the upstream
example unit file for unbound. The main difference is that we start
unbound was `unbound` user with the required capabilities instead of
letting unbound do the chroot & uid/gid changes.
The upstream unit configuration this is based on is a lot stricter with
all kinds of permissions then our previous variant. It also came with
the default of having the `Type` set to `notify`, therefore we are also
using the `unbound-with-systemd` package here. Unbound will start up,
read the configuration files and start listening on the configured ports
before systemd will declare the unit "running". This will likely help
with startup order and the occasional race condition during system
activation where the DNS service is started but not yet ready to answer
queries.
Aditionally to the much stricter runtime environmet I removed the
`/dev/urandom` mount lines we previously had in the code (that would
randomly fail during `stop`-phase).
The `preStart` script is now only required if we enabled the trust
anchor updates (which are still enabled by default).
Another beneefit of the refactoring is that we can now issue reloads via
either `pkill -HUP unbound` or `systemctl reload unbound` to reload the
running configuration without taking the daemon offline. A prerequisite
of this was that unbound configuration is available on a well known path
on the file system. I went for /etc/unbound/unbound.conf as that is the
default in the CLI tooling which in turn enables us to use
`unbound-control` without passing a custom configuration location.
