github actions on kubernetes using github app

.github/workflows/kubernetes-runner.yaml

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+###########################################################
+# IMPORTANT -> Rename the file extension to ".yaml" (remove "_") to enable this 
+###########################################################
+
+name: Self-Hosted Runner Test
+
+on: 
+  push:
+    branches:
+    - github-actions-k8s
+
+jobs:
+  build:
+    runs-on: "marcels-runner"
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: docker build python
+      run: |
+        docker build ./python/introduction/ -t python:1.0.0

github/actions/kubernetes/README.md

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+# Github Actions Runner Controller on Kubernetes
+
+Let's start with the github [actions-runner-controller](https://github.com/actions/actions-runner-controller) documentation 
+
+## Create a kubernetes cluster
+
+In this guide we we''ll need a Kubernetes cluster for testing. Let's create one using [kind](https://kind.sigs.k8s.io/) </br>
+
+```
+cd github/actions/kubernetes
+
+kind create cluster --name demo --image kindest/node:v1.28.0
+```
+
+Test the cluster:
+```
+kubectl get nodes
+NAME                 STATUS   ROLES           AGE   VERSION
+demo-control-plane   Ready    control-plane   59s   v1.28.0
+
+```
+
+Next up, I will be running a small container where I will be doing all the work from:
+You can skip this part if you already have `kubectl` and `helm` on your machine.
+
+```
+docker run -it --rm --net host -v ${HOME}/.kube/:/root/.kube/ -v ${PWD}:/work -w /work alpine sh
+```
+
+Install `kubectl`
+
+```
+apk add --no-cache curl
+curl -LO https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl
+chmod +x ./kubectl
+mv ./kubectl /usr/local/bin/kubectl
+```
+
+Install `helm`
+
+```
+HELM_VERSION=3.14.1
+curl -LO https://get.helm.sh/helm-v${HELM_VERSION}-linux-amd64.tar.gz
+tar -C /tmp/ -zxvf helm-v${HELM_VERSION}-linux-amd64.tar.gz
+rm helm-v${HELM_VERSION}-linux-amd64.tar.gz
+mv /tmp/linux-amd64/helm /usr/local/bin/helm
+chmod +x /usr/local/bin/helm
+```
+
+
+Let's go to the [Quickstart Guide](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/quickstart-for-actions-runner-controller) </br>
+
+We can deploy the controller using `helm`
+```
+VERSION=0.8.2
+NAMESPACE="github"
+helm install arc \
+    --namespace "${NAMESPACE}" \
+    --create-namespace \
+    --version ${VERSION} \
+    oci://ghcr.io/actions/actions-runner-controller-charts/gha-runner-scale-set-controller
+
+```
+
+Once chart is deployed, we can see the controller running in the `github` namespace
+
+```
+kubectl -n github get pods
+```
+
+Now this pod will not do anything, since its not authenticated with any Github organisation or repository </br>
+We can check the logs to see what it's doing: 
+
+```
+kubectl -n github logs -l app.kubernetes.io/name=gha-rs-controller
+```
+
+To make it useful, we need to add it to our repo or organisation by [Authenticating to Github](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/authenticating-to-the-github-api)
+
+
+Create a new [Github App](https://docs.github.com/en/apps/using-github-apps/installing-your-own-github-app) for your account or organization.  
+
+
+Once we have created our Github App, we need to configure its authentication by creating a kubernetes secret with the authentication details of the app. </br>
+When we have a `.pem` file , we can convert it to a single line: 
+
+`awk 'NF {sub(/\r/, ""); printf "%s\\n",$0;}' yourfile.pem`
+
+```
+kubectl create secret generic github-app-secret \
+   --namespace=github \
+   --from-literal=github_app_id=xxxxx \
+   --from-literal=github_app_installation_id=xxxxx \
+   --from-literal=github_app_private_key='-----BEGIN RSA PRIVATE KEY-----xxxxxx-----END RSA PRIVATE KEY-----'
+
+```
+Now we can upgrade our chart to apply the authentication changes
+
+```
+VERSION=0.8.2
+NAMESPACE="github"
+helm upgrade arc \
+    --namespace "${NAMESPACE}" \
+    --create-namespace \
+    --version ${VERSION} \
+    --values values.yaml \
+    oci://ghcr.io/actions/actions-runner-controller-charts/gha-runner-scale-set-controller
+```
+
+## Create your own runner
+
+The [documentation](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/deploying-runner-scale-sets-with-actions-runner-controller#configuring-the-runner-image) showcases how to customise the runner with the helm values file 
+
+This allows us to customer the pod template for our runner. <br/>
+Let's create a basic one:
+
+```
+template:
+  spec:
+    containers:
+      - name: runner
+        image: "custom-registry.io/actions-runner:latest"
+        imagePullPolicy: Always
+        command: ["/home/runner/run.sh"]
+```
+
+We'll need to use the helm upgrade to apply the changes again. </br>
+
+We can also set our runner name using the values file using the [advanced configuration options](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/deploying-runner-scale-sets-with-actions-runner-controller#using-advanced-configuration-options)
+
+```
+runnerScaleSetName: "marcels-runner"
+```

github/actions/kubernetes/values.yaml

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+githubConfigSecret: github-app-secret
+runnerScaleSetName: "marcels-runner"
+template:
+  spec:
+    containers:
+      - name: runner
+        image: "custom-registry.io/actions-runner:latest"
+        imagePullPolicy: Always
+        command: ["/home/runner/run.sh"]