Gitlab runner LXD

https://docs.gitlab.com/runner/executors/custom_examples/lxd/

You need to install the gitlab-runner apt package first.

Installing the package creates the gitlab-runner system user and the /etc/gitlab-runner/ directory structure where config.toml lives.

Here is the step-by-step order of operations to get everything set up correctly:

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Step 1: Install the GitLab Runner Package

Run these commands on your host machine to add GitLab's official repository and install the runner:

# 1. Download and run the official GitLab repository setup script
curl -L "https://packages.gitlab.com/install/repositories/runner/gitlab-runner/script.deb.sh" | sudo bash

# 2. Install the gitlab-runner package
sudo apt-get install gitlab-runner

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Step 2: Create the LXD Executor Scripts

Next, create your wrapper scripts for the custom executor (e.g., in /opt/gitlab-runner/).

# Create directory for custom executor scripts
sudo mkdir -p /opt/gitlab-runner

# Create the prepare, run, and cleanup scripts
sudo touch /opt/gitlab-runner/lxd-prepare.sh
sudo touch /opt/gitlab-runner/lxd-run.sh
sudo touch /opt/gitlab-runner/lxd-cleanup.sh

# Make them executable
sudo chmod +x /opt/gitlab-runner/lxd-*.sh

(Paste the script contents into these files and ensure the LXD TLS certificate generation step you performed earlier is configured under the gitlab-runner system user's home directory so it can authenticate against LXD).

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Step 3: Register and Configure config.toml

Finally, register the runner with your GitLab instance, which will automatically generate or update /etc/gitlab-runner/config.toml.

# Register the runner (you'll need a registration token from GitLab UI)
sudo gitlab-runner register \
  --non-interactive \
  --url "https://gitlab.com/" \
  --token "YOUR_RUNNER_AUTHENTICATION_TOKEN" \
  --executor "custom" \
  --description "lxd-restricted-runner" \
  --custom-prepare-exec "/opt/gitlab-runner/lxd-prepare.sh" \
  --custom-run-exec "/opt/gitlab-runner/lxd-run.sh" \
  --custom-cleanup-exec "/opt/gitlab-runner/lxd-cleanup.sh"

Once registered, you can edit /etc/gitlab-runner/config.toml directly if you need to fine-tune concurrency limits or execution parameters.