Gitlab runner
The state of gitlab-runner in nixpkgs
As of 20.09 NixOS comes with a revamped gitlab-runner module which provides the capabilities to set up custom to meet your needs.
The services.gitlab-runner.services
documents a number of typical setups and this article gives an overview of some of the more complex setups.
Configuring a caching dockerized gitlab build runner
With the configuration defined below a gitlab runner will be created which provides a caching docker container to run nix-build.
{
boot.kernel.sysctl."net.ipv4.ip_forward" = true; # 1
virtualization.docker.enable = true;
services.gitlab-runner = {
enable = true;
services= {
# runner for building in docker via host's nix-daemon
# nix store will be readable in runner, might be insecure
nix = with lib;{
# File should contain at least these two variables:
# `CI_SERVER_URL`
# `REGISTRATION_TOKEN`
registrationConfigFile = toString ./path/to/ci-env; # 2
dockerImage = "alpine";
dockerVolumes = [
"/nix/store:/nix/store:ro"
"/nix/var/nix/db:/nix/var/nix/db:ro"
"/nix/var/nix/daemon-socket:/nix/var/nix/daemon-socket:ro"
];
dockerDisableCache = true;
preBuildScript = pkgs.writeScript "setup-container" ''
mkdir -p -m 0755 /nix/var/log/nix/drvs
mkdir -p -m 0755 /nix/var/nix/gcroots
mkdir -p -m 0755 /nix/var/nix/profiles
mkdir -p -m 0755 /nix/var/nix/temproots
mkdir -p -m 0755 /nix/var/nix/userpool
mkdir -p -m 1777 /nix/var/nix/gcroots/per-user
mkdir -p -m 1777 /nix/var/nix/profiles/per-user
mkdir -p -m 0755 /nix/var/nix/profiles/per-user/root
mkdir -p -m 0700 "$HOME/.nix-defexpr"
. ${pkgs.nix}/etc/profile.d/nix-daemon.sh
${pkgs.nix}/bin/nix-channel --add https://nixos.org/channels/nixos-20.09 nixpkgs # 3
${pkgs.nix}/bin/nix-channel --update nixpkgs
${pkgs.nix}/bin/nix-env -i ${concatStringsSep " " (with pkgs; [ nix cacert git openssh ])}
'';
environmentVariables = {
ENV = "/etc/profile";
USER = "root";
NIX_REMOTE = "daemon";
PATH = "/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:/bin:/sbin:/usr/bin:/usr/sbin";
NIX_SSL_CERT_FILE = "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt";
};
tagList = [ "nix" ];
};
};
};
}
- enabling
ip_forward
on the host machine is important for the docker container to be able to perform networking tasks (such as cloning the gitlab repo) - the
registrationConfigFile
must contain the gitlab token for registering a gitlab-runner - this line defines the default nixpkgs channel to be used inside the container