> For the complete documentation index, see [llms.txt](https://docs-lunar.earthly.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-lunar.earthly.dev/install/ci-tracer.md).

# Lunar CI Tracer

The **Lunar CI Tracer** instruments your CI runners: it wraps the runner process, watches what a build actually does, and triggers collectors at the right moments. That is how build-time facts reach the Hub, including test results, scan output, image digests, and deploy markers.

It installs on your runners rather than in the cluster, so it is independent of the Hub install and can be added at any point after it.

CI tracing is optional. Lunar still collects from pushes and merge requests without it; the tracer is what adds the build-time half.

| CI platform        | Support                                        | Setup                                                                                                                                                                                                                                         |
| ------------------ | ---------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **GitHub Actions** | Supported                                      | [Self-hosted runners](/install/ci-tracer/github-actions-self-hosted.md): install the tracer on the runner. [GitHub-managed runners](/install/ci-tracer/github-actions-managed.md): add the `earthly/lunar-ci-tracer` action to your workflow. |
| **Buildkite**      | Supported                                      | [Buildkite](/install/ci-tracer/buildkite.md): an agent command hook plus a Notification Service webhook.                                                                                                                                      |
| **GitLab CI**      | [Coming soon](/install/ci-tracer/gitlab-ci.md) | Nothing to install yet. Submit build-time facts from a job with [`lunar collect`](/docs/lunar-cli.md#lunar-collect) in the meantime.                                                                                                          |

## Choosing between the two GitHub Actions options

Both put the same tracer on the runner; they differ in where the install happens.

* [**The action**](/install/ci-tracer/github-actions-managed.md) is per workflow job, and works on GitHub-hosted *and* self-hosted runners. It is the easier starting point, and the only option when you do not control the runner image.
* [**Installing on the runner**](/install/ci-tracer/github-actions-self-hosted.md) is per-machine, so every workflow on that runner is traced without touching any workflow YAML. It needs self-hosted runners you administer.

## Shared configuration

* [Configuration reference](/install/ci-tracer/configuration-reference.md) covers every environment variable the tracer reads, on any platform.
* [Systemd](/install/ci-tracer/systemd.md) covers running the tracer as a service on a Linux host.

## Next steps

* [Git Platforms](/install/git-platforms.md) for the credentials Lunar uses to read repositories and post results.
* [Install Lunar](/install.md) for where CI integration fits in the overall install.


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