Image Overview: gha-runner-scale-set-controller

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Kubernetes controller for GitHub Actions self-hosted runners

Download this Image

The image is available on cgr.dev:

docker pull cgr.dev/chainguard/gha-runner-scale-set-controller:latest

Usage

This document outlines how to test our gha-runner-scale-set-controller image. You can set up ARC on Kubernetes using Helm, then create and run a workflow that uses runner scale sets.

For more information about runner scale sets, you should refer to the official documentation, Quickstart for Actions Runner Controller.

Prerequisites

You can find a detailed list of prerequisites in the official documentation, (here)[https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/quickstart-for-actions-runner-controller#prerequisites).

But for the sake of simplicity, all you need is:

• A Kubernetes cluster
• Helm 3
• A GitHub repository with a workflow that uses runner scale sets

that’s all.

Testing

To test the gha-runner-scale-set-controller image, you can follow these steps:

1. Install the Actions Runner Controller on your Kubernetes cluster using Helm. You can find the installation instructions here.

NAMESPACE="arc-systems"
helm install arc \
    --namespace "${NAMESPACE}" \
    --create-namespace \
    oci://ghcr.io/actions/actions-runner-controller-charts/gha-runner-scale-set-controller \
    --set image.repository=cgr.dev/chainguard/gha-runner-scale-set-controller \
    --set image.tag=latest

⚠️ Please ensure that the arc-gha-rs-controller pod is running in the arc-system namespace before proceeding to the next step.

2. To configure the runner scale set, you can follow the official documentation here.

For that, you will need two things:

• A GitHub repository with a workflow that uses runner scale sets
• A runner registration token which we refer GITHUB_PAT

INSTALLATION_NAME="arc-runner-set"
NAMESPACE="arc-runners"
GITHUB_CONFIG_URL="https://github.com/<org/repo/enterprise>" # make sure to replace this with your GitHub repository URL or GitHub Enterprise URL
GITHUB_PAT="<PAT>" # make sure to replace this with your GitHub 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/gha-runner-scale-set

⚠️ Please ensure that the arc-runner-set pod is running in the arc-runners namespace before proceeding to the next step.

⚠️ The GITHUB_PAT is not the only way to authenticate with GitHub. You can use other methods like GitHub App. You can check the values.yaml file for more information: https://github.com/actions/actions-runner-controller/blob/master/charts/gha-runner-scale-set/values.yaml

Once you did that you can create and run a workflow that uses runner scale sets like the following:

🤖 You can see the self-hosted runner that you registered within the project’s runners tab. To get more detail about using self-hosted runners in workflow, here is the official documentation you can refer to.

name: Actions Runner Controller Demo
on:
  workflow_dispatch:

jobs:
  Explore-GitHub-Actions:
    # You need to use the INSTALLATION_NAME from the previous step
    runs-on: arc-runner-set
    steps:
    - run: echo "🎉 This job uses runner scale set runners!"

That’s it! You have successfully tested the gha-runner-scale-set-controller image.