/gitlab-runner-resources-webhook

A Mutating Webhook to manage resources on the gitlab runner kubernetes executor

Primary LanguageGo

Gitlab Runner Resources Webhook

This project should not be required and is a workaround to this issue. You might want to also monitor this MR, once it's merged this repo is pointless.

It was also a good exercise to learn more about writing Admission Webhooks.

Setup

The webhook works for pods created by a gitlab runner using the kubernetes executor.

kubectl -n gitlab apply -f deploy/
kubectl -n gitlab certificate approve gitlab-resources-webhook.gitlab

Some relevant points:

  • This setup was tested with version 0.25.0 of the gitlab runner - there is a requirement that the main job container is named build, changes to this in the future would require updates on the webhook code
  • The commands above create resources in the gitlab namespace - if you change this, you'll need to also update the namespace reference to the Service in the MutatingWebhookConfiguration and the ServiceAccount in the Job definition
  • The objectSelector in the MutatingWebhookConfiguration sets the expected label for pods that should trigger the webhook. The value is preset to gpu=true but you can change this to whatever pod_labels you have in your runner config - which should look something like this:
[[runners]]
  [runners.kubernetes]
    image = "ubuntu:16.04"
    namespace_overwrite_allowed = ""
    [runners.kubernetes.pod_labels]
      gpu = "true"