nixos/virtualisation: add hostname option to oci-containers.

[Arcayr]

Description of changes

Adds the hostname option to the virtualisation.oci-containers.<name> set. This maps to the --hostname argument for podman and docker. While they can be set using extraOptions it's nicer to not. Being able to set the hostname also allows for dynamic container lookup using dnsmasq or systemd-resolved with the podman dns resolver.

Reviewed points

• changes are backward compatible
  • hostname is optional.
• removed options are declared with mkRemovedOptionModule
• changes that are not backward compatible are documented in release notes
• module tests succeed on ARCHITECTURE
• options types are appropriate
• options description is set
• options example is provided
• documentation affected by the changes is updated
  • option documentation added.

Possible improvements

Comments

Testing with the following set:

virtualisation.oci-containers.containers = {
    "hello-world" = {
      image = "docker.io/library/hello-world:latest";
      autoStart = true;
      hostname = "not-hello-world.podman";
    };
  };

$ sudo podman inspect hello-world | jq .[].Config.Hostname
"not-hello-world.podman"

$ cat /nix/store/qz4z7mnadd69p7qhi637sgng6mf75gzg-unit-script-podman-hello-world-start/bin/podman-hello-world-start
set -e
exec podman run \
  --rm \
  --name='hello-world' \
  --log-driver=journald \
  --hostname='not-hello-world.podman' \
  --cidfile=/run/podman-'hello-world'.ctr-id \
  --cgroups=no-conmon \
  --sdnotify=conmon \
  -d \
  --replace \
  docker.io/library/hello-world:latest

[vdemeester]

LGTM 🐯

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-already-reviewed/2617/1200