5. Continuous Delivery with Jenkins in Kubernetes Engine

Overview

Goal
- Set up a continuous delivery pipeline with Jenkins on Kubernetes engine.

What you’ll do
- Provision a Jenkins application into a Kubernetes Engine Cluster
- Set up your Jenkins application using Helm Package Manager
- Explore the features of a Jenkins application
- Create and execise a Kenkins pipeline

What is Kubernetes Engine?

Kubernetes Engine is Google Cloud's hosted version of Kubernetes - a powerful cluster manager and orchestration system for containers. Kubernetes is an open source project that can run on many different environments—from laptops to high-availability multi-node clusters; from virtual machines to bare metal. As mentioned before, Kubernetes apps are built on containers - these are lightweight applications bundled with all the necessary dependencies and libraries to run them. This underlying structure makes Kubernetes applications highly available, secure, and quick to deploy—an ideal framework for cloud developers.

What is Jenkins?

Jenkins is an open-source automation server that lets you flexibly orchestrate your build, test, and deployment pipelines. Jenkins allows developers to iterate quickly on projects without worrying about overhead issues that can stem from continuous delivery.

What is Continuous Delivery / Continuous Deployment?

When you need to set up a continuous delivery (CD) pipeline, deploying Jenkins on Kubernetes Engine provides important benefits over a standard VM-based deployment.

When your build process uses containers, one virtual host can run jobs on multiple operating systems. Kubernetes Engine provides ephemeral build executors—these are only utilized when builds are actively running, which leaves resources for other cluster tasks such as batch processing jobs. Another benefit of ephemeral build executors is speed—they launch in a matter of seconds.

Kubernetes Engine also comes pre-equipped with Google's global load balancer, which you can use to automate web traffic routing to your instance(s). The load balancer handles SSL termination and utilizes a global IP address that's configured with Google's backbone network—coupled with your web front, this load balancer will always set your users on the fastest possible path to an application instance.

Now that you've learned a little bit about Kubernetes, Jenkins, and how the two interact in a CD pipeline, it's time to go build one.

Ref

Jenkins on Kubernetes Engine

Download the source code

✔️ Set zone

gcloud config set compute/zone us-west1-b

✔️ Copy the lab’s sample code

gsutil cp gs://spls/gsp051/continuous-deployment-on-kubernetes.zip .
unzip continuous-deployment-on-kubernetes.zip

✔️ Change to the correct directory

cd continuous-deployment-on-kubernetes

Provisioning Jenkins

✔️ Creating a Kubernetes cluster

gcloud container clusters create jenkins-cd \\
--num-nodes 2 \\
--machine-type n1-standard-2 \\
--scopes "<https://www.googleapis.com/auth/source.read_write,cloud-platform>"

✔️ Confirm that your cluster is running

gcloud container clusters list

✔️ Get the credentials

gcloud container clusters get-credentials jenkins-cd

✔️ Confirm that you can connect to access your newly provisioned cluster

kubectl cluster-info

Setup Helm

What is Helm?
- Helm is a package manager that makes it easy to configure and deploy Kubernetes applications.

✔️ Add Helm’s stable chart repo

helm repo add jenkins <https://charts.jenkins.io>

✔️ Ensure the repo is up to date

helm repo update

Configure and Install Jenkins

When installing Jenkins, a values file can be used as a template to provide values that are necessary for setup.

custom values file

- Kubernetes:1.29.4
- Workflow-multibranch:latest
- Git:4.7.1
- Configuration-as-code:1.51
- Google-oauth-plugin:latest
- Google-source-plugin:latest
- Google-storage-plugin:latest

✔️ Download the custom values file

gsutil cp gs://spls/gsp330/values.yaml jenkins/values.yaml

✔️ Use the Helm CLI to deploy the chart with your configuration settings

helm install cd jenkins/jenkins -f jenkins/values.yaml --wait

✔️ Ensure the Jenkins pod goes to the Running state and the container is in the READT state

kubectl get pods

✔️ Configure the Jenkins service account to be able to deploy to the cluster

kubectl create clusterrolebinding jenkins-deploy --
clusterrole=cluster-admin --serviceaccount=default:cd-jenkins

✔️ Setup port forwarding to the Jenkins UI from the Cloud Shell

export POD_NAME=$(kubectl get pods --namespace default -l 
"app.kubernetes.io/component=jenkins-master" -l 
"app.kubernetes.io/instance=cd" -o jsonpath="
{.items[0].metadata.name}")
kubectl port-forward $POD_NAME 8080:8080 >> /dev/null &

✔️ Check that the Jenkins Service was created properly

kubectl get svc

Connect to Jenkins

✔️ Jenkins chart will automatically create an admin password for you.

printf $(kubectl get secret cd-jenkins -o jsonpath="
{.data.jenkins-admin-password}" | base64 --decode);echo

✔️ To get to the Jenkins user interface, click on the Web Preview button in cloud shell, then click Preview on port 8080

Understanding the Application

Deploy the sample application, gceme, in your continuous deployment pipeline.

Deploying the Application

Environments

Production : The live site that your users access
Canary : A smaller-capacity site that receives only a percentage of your user traffic. Use this environment to validate your software with live traffic before it's released to all of your users.

✔️ Navigate to the sample application directory

cd sample-app

✔️ Create the Kubernetes namespace to logically isolate the deployment

kubectl create ns production

✔️ Create the production and canary deployments, and the services

kubectl create ns production

✔️ Create the production and canary deployments, and the services

kubectl apply -f k8s/production -n production

kubectl apply -f k8s/canary -n production

kubectl apply -f k8s/services -n production

✔️ Scale up the production environment frontends

kubectl scale deployment gceme-frontend-production 
-n production --replicas 4

✔️ Now confirm that you have 5 pods running for the frontend, 4 for production traffic and 1 for canary releases (changes to the canary release will only affect 1 out of 5 (20%) of users)

kubectl get pods -n production -l app=gceme -l role=frontend

✔️ Confirm that you have 2 pods for the backend, 1 for production and 1 for canary

kubectl get pods -n production -l app=gceme -l role=backend

✔️ Retrieve the external IP for the production services

kubectl get service gceme-frontend -n production

✔️ Store the frontend service load balancer IP in an environment cariable for use later

export FRONTEND_SERVICE_IP=$(kubectl get -o jsonpath="
{.status.loadBalancer.ingress[0].ip}" --namespace=production 
services gceme-frontend)

✔️ Confirm that both services are working by opening the frontend external IP address in your browser. Check the version output of the service by running the following command

curl http://$FRONTEND_SERVICE_IP/version

set up a pipeline for deploying your changes continuously and reliably.

Creating the Jenkins Pipeline

✔️ Creating a repository to host the sample app source code

gcloud source repos create default

✔️ Initialize the sample-app directory as its own Git repository

git init

git config credential.helper gcloud.sh

git remote add origin 
<https://source.developers.google.com/p/$DEVSHELL_PROJECT_ID/r/default>

Set the username and email address. Add, commit, and push the files.

git config --global user.email "[EMAIL_ADDRESS]"
git config --global user.name "[USERNAME]"

git add .
git commit -m "Initial commit"
git push origin master

✔️ Adding yout service account credentials

Step 1: In the Jenkins user interface, click Manage Jenkins in the left navigation then click Manage Credentials.
Step 2: Click Jenkins
Step 3: Click Global credentials (unrestricted).
Step 4: Click Add Credentials in the left navigation.
Step 5: Select Google Service Account from metadata from the Kind drop-down and click OK.

✔️ Creating the Jenkins job

Step 1: Click New Item in the left navigation:
Step 2: Name the project sample-app, then choose the Multibranch Pipeline option and click OK.
Step 3: On the next page, in the Branch Sources section, click Add Source and select git.
Step 4: Paste the HTTPS clone URL of your sample-app repo in Cloud Source Repositories into the Project Repository field. Replace [PROJECT_ID] with your Project ID:
```
<https://source.developers.google.com/p/[PROJECT_ID]/r/default>
```
Step 5: From the Credentials drop-down, select the name of the credentials you created when adding your service account in the previous steps.
Step 6: Under Scan Multibranch Pipeline Triggers section, check the Periodically if not otherwise run box and set the Interval value to 1 minute.
Step 7: Your job configuration should look like this:
Step 8: Click Save leaving all other options with their defaults.

Creating the Development Environment

✔️ Creating a development branch

git checkout -b new-feature

✔️ Modifying the pipeline definition

Open the Jenkinsfile in your terminal editor

vi Jenkinsfile

PROJECT = "REPLACE_WITH_YOUR_PROJECT_ID"
APP_NAME = "gceme"
FE_SVC_NAME = "${APP_NAME}-frontend"
CLUSTER = "jenkins-cd"
CLUSTER_ZONE = "us-west1-b"
IMAGE_TAG = "gcr.io/${PROJECT}/${APP_NAME}:${env.BRANCH_NAME}.${env.BUILD_NUMBER}"
JENKINS_CRED = "${PROJECT}"

✔️ Modify the site

Change the gceme card from blue to orange

vi html.go

<div class="card orange">

vi main.go

const version string = "2.0.0"

Kick off Deployment

✔️ Commit and push your changes

git add Jenkinsfile html.go main.go
git commit -m "Version 2.0.0"
git push origin new-feature

✔️ Start the proxy in the background

kubectl proxy &

✔️ Verify that your application is accessible by sending a request yo localhost and letting kubectl proxy forward it to your service

curl \\
<http://localhost:8001/api/v1/namespaces/new->
feature/services/gceme-frontend:80/proxy/version

Deploying a Canary Release

✔️ Create a canary branch and push it to the Git server

git checkout -b canary
git push origin canary

✔️ Check the service URL to ensure that some of the traffic is being served by your new version. Your should see about 1 in 5 requests (in no particular order) returning version 2.0.0 .

export FRONTEND_SERVICE_IP=$(kubectl get -o \\
jsonpath="{.status.loadBalancer.ingress[0].ip}" --
namespace=production services gceme-frontend)

while true; do curl http://$FRONTEND_SERVICE_IP/version; 
sleep 1; done

Deploying to production

✔️ Create a canary branch and push it to the Git server

git checkout master
git merge canary
git push origin master

✔️ Check the service URL to ensure that all of the traffic is being served by your new version, 2.0.0.

export FRONTEND_SERVICE_IP=$(kubectl get -o \\
jsonpath="{.status.loadBalancer.ingress[0].ip}" --
namespace=production services gceme-frontend)

while true; do curl http://$FRONTEND_SERVICE_IP/version; 
sleep 1; done

✔️ Navigate to site on which the gceme application displays the info cards.

kubectl get service gceme-frontend -n production

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export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/component=jenkins-master" -l "app.kubernetes.io/instance=cd" -o jsonpath=" {.items[0].metadata.name}") kubectl port-forward $POD_NAME 8080:8080 >> /dev/null &

PROJECT = "REPLACE_WITH_YOUR_PROJECT_ID" APP_NAME = "gceme" FE_SVC_NAME = "${APP_NAME}-frontend" CLUSTER = "jenkins-cd" CLUSTER_ZONE = "us-west1-b" IMAGE_TAG = "gcr.io/${PROJECT}/${APP_NAME}:${env.BRANCH_NAME}.${env.BUILD_NUMBER}" JENKINS_CRED = "${PROJECT}"