Setup of self-hosted GitHub Actions Runners (#16)

Author: ar9708

docs/github-actions-runners.md

@@ -0,0 +1,76 @@
+# GitHub Actions Runner Setup
+
+This setup guide follows the GitHub Docs on
+[GitHub Actions / Self-hosted runners / Actions Runner Controller / Quickstart](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/quickstart-for-actions-runner-controller).
+
+Firstly, we install the Actions Runner Controller in namespace `arc-owntube-systems`:
+
+```bash
+export CONTROLLER_NAMESPACE=arc-owntube-systems
+microk8s helm3 install arc \
+    --namespace "${CONTROLLER_NAMESPACE}" \
+    --create-namespace \
+    oci://ghcr.io/actions/actions-runner-controller-charts/gha-runner-scale-set-controller
+```
+
+And then, we need to set up authentication as a GitHub App owned by the OwnTube.tv organisation per the
+[Authenticating ARC with a GitHub App](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/authenticating-to-the-github-api#authenticating-arc-with-a-github-app)
+documentation.
+
+```bash
+export APP_ID=996240
+# from https://github.com/organizations/OwnTube-tv/settings/installations/54793885
+export INSTALLATION_ID=54793885
+export APP_PRIVATE_KEY="$(cat arc-owntube-runner.2024-09-12.private-key.pem)"
+export RUNNER_NAMESPACE=arc-owntube-runner
+microk8s kubectl create namespace $RUNNER_NAMESPACE
+microk8s kubectl create secret generic pre-defined-secret \
+   --namespace=$RUNNER_NAMESPACE \
+   --from-literal=github_app_id=$APP_ID \
+   --from-literal=github_app_installation_id=$INSTALLATION_ID \
+   --from-literal=github_app_private_key="$APP_PRIVATE_KEY"
+```
+
+Now, configure a runner scale set:
+
+```bash
+export INSTALLATION_NAME="arc-owntube-runner"
+export RUNNER_NAMESPACE=arc-owntube-runner
+export GITHUB_CONFIG_URL="https://github.com/OwnTube-tv"
+microk8s helm install "${INSTALLATION_NAME}" \
+    --namespace "${RUNNER_NAMESPACE}" \
+    --create-namespace \
+    --set githubConfigUrl="${GITHUB_CONFIG_URL}" \
+    --set githubConfigSecret=pre-defined-secret \
+    oci://ghcr.io/actions/actions-runner-controller-charts/gha-runner-scale-set
+```
+
+Run the following command to check your installation:
+
+```bash
+microk8s helm list -A
+'NAME              	NAMESPACE          	...	STATUS  	CHART                                	APP VERSION'
+'arc               	arc-owntube-systems	...	deployed	gha-runner-scale-set-controller-0.9.3	0.9.3      '
+'arc-owntube-runner	arc-owntube-runner 	...	deployed	gha-runner-scale-set-0.9.3           	0.9.3      '
+```
+
+Check the manager pod:
+
+```bash
+microk8s kubectl get pods -n arc-owntube-systems
+'NAME                                     READY   STATUS    RESTARTS   AGE  '
+'arc-gha-rs-controller-66c95d466b-wb5rt   1/1     Running   0          3h21m'
+'arc-owntube-runner-79d95874-listener     1/1     Running   0          4m7s '
+```
+
+Continue with the [Using runner scale sets](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/quickstart-for-actions-runner-controller#using-runner-scale-sets)
+verification steps from the GitHub Docs to ensure everything is set up correctly.
+
+When jobs are picked up successfully by the controller, they appear as short-lived pods in
+the `arc-owntube-runner` namespace:
+
+```bash
+microk8s kubectl get pods -n arc-owntube-runner
+'NAME                                    READY   STATUS    RESTARTS   AGE'
+'arc-owntube-runner-zrcd7-runner-2dn2k   1/1     Running   0          32s'
+```