Deploying to Google Kubernetes Engine

Introduction

This guide explains how to use GitHub Actions to build a containerized application, push it to Google Container Registry (GCR), and deploy it to Google Kubernetes Engine (GKE).

GKE is a managed Kubernetes cluster service from Google Cloud that can host your containerized workloads in the cloud or in your own datacenter. For more information, see Google Kubernetes Engine.

Prerequisites

Before you proceed with creating the workflow, you will need to complete the following steps for your Kubernetes project. This guide assumes the root of your project already has a Dockerfile and a Kubernetes Deployment configuration file. For an example, see google-github-actions.

Creating a GKE cluster

To create the GKE cluster, you will first need to authenticate using the gcloud CLI. For more information on this step, see the following articles:

• gcloud auth login
• gcloud CLI
• gcloud CLI and Cloud SDK

For example:

$ gcloud container clusters create $GKE_CLUSTER \
	--project=$GKE_PROJECT \
	--zone=$GKE_ZONE

Enabling the APIs

Enable the Kubernetes Engine and Container Registry APIs. For example:

$ gcloud services enable \
	containerregistry.googleapis.com \
	container.googleapis.com

Configuring a service account and storing its credentials

This procedure demonstrates how to create the service account for your GKE integration. It explains how to create the account, add roles to it, retrieve its keys, and store them as a base64-encoded encrypted repository secret named GKE_SA_KEY.

1. Create a new service account:

   $ gcloud iam service-accounts create $SA_NAME
   

2. Retrieve the email address of the service account you just created:

   $ gcloud iam service-accounts list
   

3. Add roles to the service account. Note: Apply more restrictive roles to suit your requirements.

   $ gcloud projects add-iam-policy-binding $GKE_PROJECT \
     --member=serviceAccount:$SA_EMAIL \
     --role=roles/container.admin \
     --role=roles/storage.admin
   

4. Download the JSON keyfile for the service account:

   $ gcloud iam service-accounts keys create key.json --iam-account=$SA_EMAIL
   

5. Store the project ID as a secret named GKE_PROJECT:

   $ export GKE_SA_KEY=$(cat key.json | base64)
   

(Optional) Configuring kustomize

Kustomize is an optional tool used for managing YAML specs. After creating a kustomization file, the workflow below can be used to dynamically set fields of the image and pipe in the result to kubectl. For more information, see kustomize usage.

Creating the workflow

Once you've completed the prerequisites, you can proceed with creating the workflow.

The following example workflow demonstrates how to build a container image and push it to GCR. It then uses the Kubernetes tools (such as kubectl and kustomize) to pull the image into the cluster deployment.

name: Build and Deploy to GKE

on:
  release:
    types: [created]

env:
  PROJECT_ID: ${{ secrets.GKE_PROJECT }}
  GKE_CLUSTER: cluster-1    # Add your cluster name here.
  GKE_ZONE: us-central1-c   # Add your cluster zone here.
  DEPLOYMENT_NAME: gke-test # Add your deployment name here.
  IMAGE: static-site

jobs:
  setup-build-publish-deploy:
    name: Setup, Build, Publish, and Deploy
    runs-on: ubuntu-latest
    steps:

    - name: Checkout
      uses: actions/checkout@v2

    # Setup gcloud CLI
    - uses: google-github-actions/setup-gcloud@v0.2.0
      with:
        service_account_key: ${{ secrets.GKE_SA_KEY }}
        project_id: ${{ secrets.GKE_PROJECT }}

    # Configure docker to use the gcloud command-line tool as a credential helper
    - run: |-
        gcloud --quiet auth configure-docker

    # Get the GKE credentials so we can deploy to the cluster
    - uses: google-github-actions/get-gke-credentials@v0.2.1
      with:
        cluster_name: ${{ env.GKE_CLUSTER }}
        location: ${{ env.GKE_ZONE }}
        credentials: ${{ secrets.GKE_SA_KEY }}

    # Build the Docker image
    - name: Build
      run: |-
        docker build \
          --tag "gcr.io/$PROJECT_ID/$IMAGE:$GITHUB_SHA" \
          --build-arg GITHUB_SHA="$GITHUB_SHA" \
          --build-arg GITHUB_REF="$GITHUB_REF" \
          .

    # Push the Docker image to Google Container Registry
    - name: Publish
      run: |-
        docker push "gcr.io/$PROJECT_ID/$IMAGE:$GITHUB_SHA"

    # Set up kustomize
    - name: Set up Kustomize
      run: |-
        curl -sfLo kustomize https://github.com/kubernetes-sigs/kustomize/releases/download/v3.1.0/kustomize_3.1.0_linux_amd64
        chmod u+x ./kustomize

    # Deploy the Docker image to the GKE cluster
    - name: Deploy
      run: |-
        ./kustomize edit set image gcr.io/PROJECT_ID/IMAGE:TAG=gcr.io/$PROJECT_ID/$IMAGE:$GITHUB_SHA
        ./kustomize build . | kubectl apply -f -
        kubectl rollout status deployment/$DEPLOYMENT_NAME
        kubectl get services -o wide

Additional resources

For more information on the tools used in these examples, see the following documentation:

• For the full starter workflow, see the "Build and Deploy to GKE" workflow.
• For more starter workflows and accompanying code, see Google's GitHub Actions example workflows.
• The Kubernetes YAML customization engine: Kustomize.
• "Deploying a containerized web application" in the Google Kubernetes Engine documentation.