page_type: sample description: Learn how to deploy self-hosted GitHub Actions Runners on AKS (Azure Kubernetes Service) languages:

• bicep
• dockerfile products:
• azure-kubernetes-service

• github

Self-Hosted GitHub Actions Runner On AKS (Azure Kubernetes Service) with auto-scale option

This repo will demo shortly how you can connect to your github account a self-hosted runner which deployed on Azure Kubernetes Service (AKS) with auto-scale option - which provide an ability to handle successfully many github action job requests in parallel. This project include the following:

• Bicep deployment, which responsible to following tasks:
  • AKS deployment
  • Install GitHub Actions Runner Controller (ARC) on AKS with auto-scale configuration
• Deploying sample app using the installed self-hosted runner to AKS cluster without keeping Azure password in Github account

Simple Diagram of End State

After deployment, the outcome will be:

Features

This project framework provides the following features:

• Self-Hosted GitHub Action Runner over AKS
• Auto-Scale Github Action runner based on 'waiting number of jobs in the queue' metric

Getting Started

Prerequisites

• Fork this repo to your github account
• In the forked repo Configure OpenID Connect in Azure. After completing the instructions, the following secrets should be created in your repo secrets: AZURE_CLIENT_ID, AZURE_SUBSCRIPTION_ID, AZURE_TENANT_ID
• Create additional GitHub Secrets in the repo:
  • name: SSH_PUBLIC_KEY, value: [public key of ssh key which will be used during AKS creation]
  • name: RUNNER_TOKEN, value: Create a new personal access token by login with a GitHub account that has admin privileges for your repo, and create a PAT with the appropriate scopes - for this sample:
  • repo (Full Control)
  • write:packages

Installation

Follow this instructions:

• Execute the Github Action - Build and Publish a runner image to ghcr
• Go to actions-runner-controller, replace ghcr.io/yaronpri/githubrunneronaks:main with the full image name from previous step, this step is necessary in order to use a GitHub runner image with Azure CLI and kubectl as part of the image
• Go to hra-scaler, replace GithubRunnerOnAKS with your repository name
• Execute the GitHub Action - IaC deployment

Using images from private registry

When using private images, the RunnerDeployment will not be able to pull your image.
To use a private registry (e.g ghcr.io with visibility set to private) add the following:

• Go to IaC deployment and add the following:

# When using private registry, we need to create a secret for that as well
kubectl create secret docker-registry runnersecret \
  --docker-server=https://${{ env.REGISTRY }}/ \
  --docker-username=${{ github.repository }} \
  --docker-password=${{ secrets.RUNNER_TOKEN }}

• Go to runnerdeployment and append:

    spec:
      repository: yaronpri/GithubRunnerOnAKS
      #organization: <YOUR ORG NAME IF WANT TO WORK AT ORG LEVEL> 
      image: ghcr.io/yaronpri/GithubRunnerOnAKS:<tag>
      imagePullSecrets:
      - name: runnersecret

Demo

In order to test the auto-scale of the runners, execute several times the GitHub Action - Deploy Sample App You will notice that after a while, a new runners are being added and able to pull the newly created jobs and process all of them in parallel

Resources

• Read more about GitHub Actions Runner Controller (ARC) here
• Read more how to change runner default image in this great blog