K8s Hooks

Description

This implementation provides a way to dynamically spin up jobs to run container workflows, rather then relying on the default docker implementation. It is meant to be used when the runner itself is running in k8s, for example when using the Actions Runner Controller

Pre-requisites

Some things are expected to be set when using these hooks

The runner itself should be running in a pod, with a service account with the following permissions

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: default
  name: runner-role
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "list", "create", "delete"]
- apiGroups: [""]
  resources: ["pods/exec"]
  verbs: ["get", "create"]
- apiGroups: [""]
  resources: ["pods/log"]
  verbs: ["get", "list", "watch",]
- apiGroups: ["batch"]
  resources: ["jobs"]
  verbs: ["get", "list", "create", "delete"]
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get", "list", "create", "delete"]

The ACTIONS_RUNNER_POD_NAME env should be set to the name of the pod
The ACTIONS_RUNNER_REQUIRE_JOB_CONTAINER env should be set to true to prevent the runner from running any jobs outside of a container
The runner pod should map a persistent volume claim into the _work directory
- The ACTIONS_RUNNER_CLAIM_NAME env should be set to the persistent volume claim that contains the runner's working directory, otherwise it defaults to ${ACTIONS_RUNNER_POD_NAME}-work
Some actions runner env's are expected to be set. These are set automatically by the runner.
- RUNNER_WORKSPACE is expected to be set to the workspace of the runner
- GITHUB_WORKSPACE is expected to be set to the workspace of the job

Limitations

A job containers will be required for all jobs
Building container actions from a dockerfile is not supported at this time
Container actions will not have access to the services network or job container network
Docker create options are not supported