An Introduction to Jenkins & Continous Integration

Just a little something to introduce some people to CI/CD with Jenkins

Requirements

You will need Docker and Docker Compose, check you have both with this command...

docker -v && docker-compose -v 

Preparation

Fork https://github.com/WillGibson/jenkins-workshop to your GitHub account, clone your fork. to your machine and cd jenkins-workshop.

Sample App

A hacked together Flask API in a docker container

Build: ./build.sh

Run: ./run.sh

Test: ./dockertest.sh

Jenkins

Setting up Jenkins

• Move into the jenkins folder cd jenkins

• Fire up Jenkins in a Docker container with Docker Compose docker-compose up

• Hit http://localhost:8080/ and log in with the admin password you got in the output from the previous command

• Install suggested plugins

• Create your admin user and click through past "Save and continue"

Setting up our pipeline

• Click "Create a job"

• Enter a name, select "Pipeline" and click "OK"

• General

  • Check "Do not allow concurrent builds"

  • Check "GitHub project" and enter the URL "https://github.com/<your_github_username>/jenkins-workshop"

  • Check "This project is parameterised"

    • Select "String parameter"
    • Enter "BRANCH" for the name
    • Enter "master" as the default

• Build Triggers

  • Ignore this for now

• Advanced Project Options

  • Ignore this for now

• Pipeline

  • Select "Pipeline script from SCM" (Source Code Management)

  • Enter the repository URL "https://github.com/<your_github_username>/jenkins-workshop"

  • Delete the "Branch Specifier" (so it can build any branch based on the branch parameter)

  • Uncheck "Lightweight checkout"

• Click "Save"

Deploying to Heroku

• (Create a Heroku account](https://signup.heroku.com/login)

• Create a Heroku app

• Set the stack of your app to container heroku stack:set container

• Connect the app to your Git repository

• Create a deploy key

  • cd .ssh
  • ssh-keygen -t rsa -b 4096 -C "[email protected]"
  • cd ../

• Add the deploy key to you GitHub repo with write access

Useful commands

• Log into the jenkins container docker exec -it jenkins_workshop /bin/bash

• Run the Jenkins container in the background docker-compose up -d

• Stop the Jenkins container if you ran it in the background docker-compose down

References

• https://github.com/jenkinsci/docker/blob/master/README.md

• https://www.jenkins.io/doc/book/pipeline/jenkinsfile/

• https://itnext.io/docker-in-docker-521958d34efd

• https://www.cloudbees.com/blog/getting-started-blue-ocean

• https://devcenter.heroku.com/articles/build-docker-images-heroku-yml