Jenkins Demo Pipeline

Purpose

• Run Jenkins in Docker - ./jenkins-docker/controller and ./docker-compose.ci.yml
  • Attach build nodes as seperate containers - ./jenkins-docker/agent
• Run Jenkinsfile pipeline on our app - ./src
  • pylint, pytest, etc. - ./Jenkinsfile
  • Build image of our app and push to custom registry - ./Dockerfile.app
• Run custom Docker Registry - ./docker-compose.registry.yml

How to Run

You may need DOCKER_BUILDKIT=0 to complete this pipeline.

1. Start the local Docker Registry:

# start local docker registry at localhost:5000
docker-compose -f ./docker-compose.registry.yml up

Then we need jenkins-controller and jenkins-agent images in our custom registry.

2. Prepare Controller Image

# build Jenkins controller image and push to local registry
pushd jenkins-docker/controller
docker build -t jenkins-controller .
docker tag jenkins-controller:latest localhost:5000/jenkins-controller:latest
docker push localhost:5000/jenkins-controller:latest
popd

3. Prepare Agent Image

# build Jenkins agent image and push to local registry
pushd jenkins-docker/agent
docker build -t jenkins-agent .
docker tag jenkins-agent:latest localhost:5000/jenkins-agent:latest
docker push localhost:5000/jenkins-agent:latest
popd

4. Start Jenkins

# pull local controller and agent images and run
docker-compose -f ./docker-compose.ci.yml up

Setup a Pipeline

When Jenkins is ready, visit http://localhost:8080/ to setup your first job. The default admin credentials are admin:admin. Create a "Pipeline" with any name. Configure your Jenkinsfile to pull from your SCM (or this repo) and provide credentials if necessary.

The jenkins-agent we built & ran before will already be connected to jenkins-controller as a build node by this point. Visit http://localhost:8080/manage/computer/ to manage connected nodes.

Once your Pipeline is setup, press the "Build Now" action in the sidebar to kick off the first build process. It will begin executing steps from within Jenkinsfile which is currently configured to lint code, run unit tests, build an image from Dockerfile.app and then push that image to our local registry as demo-app:$BUILD_NUMBER.

You can confirm the entire pipeline completed by checking http://localhost:5000/v2/_catalog to confirm that demo-app, jenkins-controller, and jenkins-agent are available in the local registry.

How to Integrate

Integrating this demo with your project shouldn't be too hard as most everything is automated and (currently) up-to-date. Here are my recommendations:

• Modify the agent/Dockerfile to fit your Jenkins pipeline. This is currently setup with the ubuntu:18.04 base image, python3.9 and pip3.9
• Move the Jenkinsfile into a seperate repo with the src/ folder containing your app's code
  • Move Dockerfile.app and .dockerignore too
• Use the remaining files as your CI repository