helm: consider handling readiness / liveness with HTTP probe instead
Just noticed that Helm [deployment template](https://gitlab.com/gitlab-org/charts/gitlab-runner/-/blob/main/templates/deployment.yaml#L80-95) using the following commands for probes:
* Liveness: `command: ["/bin/bash", "/configmaps/check-live", "{{ default 4 .Values.probeTimeoutSeconds | add -1 | max 1 }}"]`
* Readiness: `command: ["/usr/bin/pgrep","gitlab.*runner"]`
FWIW, you should provide HTTP probes here instead for more reliable healthz handling. Imagine process is running somehow but app doesn't expose any endpoint / port. So `/healthz` endpoint should return `200 OK`. And also the following above commands requires having `bash` and `pgrep` binaries in the image.
You could just provide: `/livez` and `/readyz` endpoints in the gitlab-runner.
Related doc: https://gitlab.com/gitlab-org/gitlab-runner/-/blob/main/docs/install/kubernetes-agent.md?plain=1#L214
See Kubernetes doc: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/
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