Jenkins in Kubernetes

This repository has a Dockerfile and a helm chart for setting up a simple Jenkins master for running in Kubernetes.

This Jenkins has the required tools to work in and with Kubernetes

Jenkins application with pre-loaded plugins (see plugins.txt)
Skipped setup wizard
- You can control admin user and password with --set adminUser=${USER},adminPassword=${PASSWORD}
- You can add and remove plugins by editing the plugins.txt file
Docker for managing a Docker CI lifecycle
kubectl command line client for working with the Kubernetes API
helm for managing your helm charts CI/CD lifecycle

IMPORTANT: This example is for demo and testing. It should not be used a production environment!

Get the example Docker image

You can pull an already built version of this Jenkins image from bintray.com.

# Pull the image
docker pull eldada-docker-examples.bintray.io/jenkins:lts-k8s-20190827

Build the Jenkins Docker image

You can build the image yourself

export DOCKER_REG=SET_YOUR_DOCKER_REGISTRY_HERE

# Build the image
docker build -t ${DOCKER_REG}/jenkins:lts-k8s .

# Push the image
docker push ${DOCKER_REG}/jenkins:lts-k8s

Test your image

You can run your container locally, if you have Docker installed

Using the pre-built image

# Run the container you built before
docker run -d --name jenkins -p 8080:8080 -v /var/run/docker.sock:/var/run/docker.sock eldada-docker-examples.bintray.io/jenkins:lts-k8s-20190827

Using your built image

# Run the container you built before
docker run -d --name jenkins -p 8080:8080 -v /var/run/docker.sock:/var/run/docker.sock ${DOCKER_REG}/jenkins:lts-k8s

Browse to http://localhost:8080 on your local browser

Deploy Jenkins helm chart to Kubernetes

If you are using the pre-built image eldada-docker-examples.bintray.io/jenkins:lts-k8s, you can install the helm chart with

# Init helm and tiller on your cluster
helm init

# Deploy the Jenkins helm chart
# (same command for install and upgrade)
helm upgrade --install jenkins ./helm/jenkins-k8s

NOTE: This helm chart deploys a pod with two containers. One for the Docker daemon and another for Jenkins. This is based on the suggestion in https://applatix.com/case-docker-docker-kubernetes-part-2/

If you are building your own version of Jenkins, you need your Kubernetes cluster to be able to pull the Docker image. You have to create a Docker registry secret and reference to it in your helm install command.

# Create a Docker registry secret
export DOCKER_REG=SET_YOUR_DOCKER_REGISTRY_HERE
export DOCKER_USR=SET_YOUR_DOCKER_USERNAME_HERE
export DOCKER_PWD=SET_YOUR_DOCKER_PASSWORD_HERE
export DOCKER_EML=SET_YOUR_DOCKER_EMAIL_HERE

kubectl create secret docker-registry docker-reg-secret \
        --docker-server=${DOCKER_REG} \
        --docker-username=${DOCKER_USR} \
        --docker-password=${DOCKER_PWD} \
        --docker-email=${DOCKER_EML}


# Deploy the Jenkins helm chart
# (same command for install and upgrade)
helm upgrade --install jenkins \
        --set imagePullSecrets=docker-reg-secret \
        --set image.repository=${DOCKER_REG}/jenkins \
        --set image.tag='lts-k8s' \
        ./helm/jenkins-k8s

Data persistence

By default, in Kubernetes, the Jenkins deployment uses a persistent volume claim that is mounted to /var/jenkins_home. This assures your data is saved across crashes, restarts and upgrades.

Vagrant

You can test your Docker image using Vagrant. The enclosed Vagrantfile will provision an Ubuntu VM with Docker.

Spin up the Vagrant VM then build and run the Docker image

# Spin up the Vagrant VM
vagrant up

# SSH into the VM
vagrant ssh

# Go to the mounted sources repository
cd /opt/provisioning

# Build and run your Jenkins container as shown above

Browse to http://localhost:8080 on your local browser

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