actions-runner-controller/docs/preview/actions-runner-controller-2

Autoscaling Runner Scale Sets mode

⚠️ This mode is currently only available for a limited number of organizations.

This new autoscaling mode brings numerous enhancements (described in the following sections) that will make your experience more reliable and secure.

How it works

In addition to the increased reliability of the automatic scaling, we have worked on these improvements:

• No longer require cert-manager as a prerequisite for installing actions-runner-controller
• Reliable scale-up based on job demands and scale-down to zero runner pods
• Reduce API requests to api.github.com, no more API rate-limiting problems
• The GitHub Personal Access Token (PAT) or the GitHub App installation token is no longer passed to the runner pod for runner registration
• Maximum flexibility for customizing your runner pod template

Demo

https://user-images.githubusercontent.com/568794/212668313-8946ddc5-60c1-461f-a73e-27f5e8c75720.mp4

Setup

Prerequisites

1. Create a K8s cluster, if not available.
   • If you don't have a K8s cluster, you can install a local environment using minikube. See installing minikube.
2. Install helm 3, if not available. See installing Helm.

Install actions-runner-controller

1. Install actions-runner-controller using helm 3. For additional configuration options, see values.yaml

   NAMESPACE="arc-systems"
   helm install arc \
       --namespace "${NAMESPACE}" \
       --create-namespace \
       oci://ghcr.io/actions/actions-runner-controller-charts/actions-runner-controller-2 \
       --version 0.1.0
   

2. Generate a Personal Access Token (PAT) or create and install a GitHub App. See Creating a personal access token and Creating a GitHub App.

   • ℹ For the list of required permissions, see Authenticating to the GitHub API.

3. You're ready to install the autoscaling runner set. For additional configuration options, see values.yaml

   • ℹ Choose your installation name carefully, you will use it as the value of runs-on in your workflow.
   • ℹ We recommend you choose a unique namespace in the following steps. As a good security measure, it's best to have your runner pods created in a different namespace than the one containing the manager and listener pods.

   # Using a Personal Access Token (PAT)
   INSTALLATION_NAME="arc-runner-set" 
   NAMESPACE="arc-runners"
   GITHUB_CONFIG_URL="https://github.com/<your_enterprise/org/repo>"
   GITHUB_PAT="<PAT>"
   helm install "${INSTALLATION_NAME}" \
       --namespace "${NAMESPACE}" \
       --create-namespace \
       --set githubConfigUrl="${GITHUB_CONFIG_URL}" \
       --set githubConfigSecret.github_token="${GITHUB_PAT}" \
       oci://ghcr.io/actions/actions-runner-controller-charts/auto-scaling-runner-set --version 0.1.0
   

   # Using a GitHub App
   INSTALLATION_NAME="arc-runner-set" 
   NAMESPACE="arc-runners"
   GITHUB_CONFIG_URL="https://github.com/<your_enterprise/org/repo>" 
   GITHUB_APP_ID="<GITHUB_APP_ID>"
   GITHUB_APP_INSTALLATION_ID="<GITHUB_APP_INSTALLATION_ID>"
   GITHUB_APP_PRIVATE_KEY="<GITHUB_APP_PRIVATE_KEY>"
   helm install arc-runner-set \
       --namespace "${NAMESPACE}" \
       --create-namespace \
       --set githubConfigUrl="${GITHUB_CONFIG_URL}" \
       --set githubConfigSecret.github_app_id="${GITHUB_APP_ID}" \
       --set githubConfigSecret.github_app_installation_id="${GITHUB_APP_INSTALLATION_ID}" \
       --set githubConfigSecret.github_app_private_key="${GITHUB_APP_PRIVATE_KEY}" \
       oci://ghcr.io/actions/actions-runner-controller-charts/auto-scaling-runner-set --version 0.1.0
   

4. Check your installation. If everything went well, you should see the following:

   $ helm list -n "${NAMESPACE}"
   
   NAME            NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                                    APP VERSION
   arc             arc-systems     1               2023-01-18 10:03:36.610534934 +0000 UTC deployed        actions-runner-controller-2-0.1.0        preview    
   arc-runner-set  arc-systems     1               2023-01-18 10:20:14.795285645 +0000 UTC deployed        auto-scaling-runner-set-0.1.0            0.1.0 
   

   $ kubectl get pods -n "${NAMESPACE}"
   
   NAME                                              READY   STATUS    RESTARTS   AGE
   arc-actions-runner-controller-2-8c74b6f95-gr7zr   1/1     Running   0          20m
   arc-runner-set-6cd58d58-listener                  1/1     Running   0          21s
   

5. In a repository, create a simple test workflow as follows. The runs-on value should match the helm installation name you used in the previous step.

   name: Test workflow
   on:
       workflow_dispatch:
   
   jobs:
   test:
       runs-on: arc-runner-set
       steps:
       - name: Hello world
           run: echo "Hello world"
   

6. Run the workflow. You should see the runner pod being created and the workflow being executed.

   $ kubectl get pods -A
   
   NAMESPACE     NAME                                              READY   STATUS    RESTARTS      AGE
   arc-systems   arc-actions-runner-controller-2-8c74b6f95-gr7zr   1/1     Running   0             27m
   arc-systems   arc-runner-set-6cd58d58-listener                  1/1     Running   0             7m52s
   arc-runners   arc-runner-set-rmrgw-runner-p9p5n                 1/1     Running   0             21s
   

Troubleshooting

Check the logs

You can check the logs of the controller pod using the following command:

# Controller logs
$ kubectl logs -n "${NAMESPACE}" -l app.kubernetes.io/name=actions-runner-controller-2

# Runner set listener logs
kubectl logs -n "${NAMESPACE}" -l runner-scale-set-listener=arc-systems-arc-runner-set

If you installed the autoscaling runner set, but the listener pod is not created

Verify that the secret you provided is correct and that the githubConfigUrl you provided is accurate.