CI Installation

Requirements

1. Docker
2. Jenkins

Install Docker

Linux

1. See Install Docker Engine on Linux.
2. if you want to use docker without sudo:
   • Remember to add yourself to the docker group. sudo groupadd docker && sudo gpasswd -a $USER docker
   • Restart the daemon:
     • In Ubuntu: sudo service docker restart
     • Other distributions: sudo systemctl restart docker

Mac OS X

1. See Getting Started with Docker for Mac.

Basic Docker Usage

Note: All commands should run with sudo permission unless you have set the docker group.

Terminologies

1. Container: VM-like instance running processes.
2. Image: Disk image for containers. Defined by a Dockerfile. You can get a lot of images from Docker Hub
3. Volume: A host directory that can be mount into container directory.

Container Management

1. Show current running containers: docker ps
2. Show all containers: docker ps -a. This includes exited dockers.
3. Show available docker images: docker images
4. Show all volumes: docker volume ls
5. To delete a container / image / volume:
   • Use 1. to 4. to get ID / NAME (something like 9e24d7d5a3be or jenkins_workspace).
   • Container: docker rm [ID]
   • Image: docker rmi [ID]
   • Volume: docker volume rm [NAME]
6. Tip: to remove all unused containers: docker ps -a | awk '{print $1}' | xargs docker rm

Running a Container

$ docker run [Options] [Docker Image] [Command]
$ docker run -v [host path / volumne name]:[container path]  -it --rm [docker image] [command] 
$ # Example:
$ docker run -v rvm:/home/jenkins/.rvm -v jenkins_workspace:/home/jenkins/workspace -it --rm joshua5201/jenkins-slave-rails /bin/bash

Prepare Docker Images

Install RVM in Image (First run only)

1. Pull image: docker pull joshua5201/jenkins-slave-rails
2. Create volume for RVM: docker volume create --name rvm
3. Create volume for Workspace: docker volume create --name jenkins_workspace
4. Install RVM in docker: docker run -v rvm:/home/jenkins/.rvm -it joshua5201/jenkins-slave-rails /bin/bash
5. Inside docker:
   • su -l jenkins
   • curl -sSL https://get.rvm.io | bash -s stable
6. You can just mount rvm volume whenever you add a docker image (~/.rvm must exists).

Available Images

1. joshua5201/jenkins-slave-rails: basic runtime
2. joshua5201/jenkins-slave-rails-pg: with postgresql installed. postgres user: jenkins, no password.

Jenkins Configuration

1. Follow the default steps and create first administrator user
2. Manage jenkins -> Manage plugins -> Available -> install docker rvm
3. Manage jenkins -> Configure system -> Add a new cloud (choose docker) ref: https://wiki.jenkins-ci.org/display/JENKINS/Docker+Plugin
   • set name, docker url (usually unix:///var/run/docker.sock)
     
     
   • Add docker template
   • Docker image: joshua5201/jenkins-slave-rails
   • Container settings -> Volumes: rvm:/home/jenkins/.rvm jenkins_workspace:/home/jenkins/workspace
   • Remote File System Root: /home/jenkins
   • Labels: docker
   • Add Credentials -> username with password -> jenkins/jenkins
     
     
     
     
4. When adding other images like jenkins-slave-rails-pg, just change the Docker image and Labels above. (e.g. docker-pg)

Create Build Job

1. New Item -> Enter name -> Choose freestyle item
2. General -> Advanced -> Custom Workspace: jenkins_workspace:/home/jenkins/workspace
   
   
3. Restrict where this project can be run: docker (or whatever labels you set for your docker image)
4. Source Code Management: git -> set repo url -> add credentials (ssh private key with username 'git')
5. Build Environment: Run the build in a RVM-managed environment -> choose your implementation (e.g. 2.3.0)
6. Add build steps: Execute shell

gem install rubygems-bundler
sudo /etc/init.d/redis-server start # if you need Redis
bundle install
bundle exec rake db:test:prepare
bundle exec rspec 

Create Deploy Job

1. To avoid SSH problems, please use the same key for GitHub repo deploy key and the key for SSH login to staging / production server.
2. Follow the same steps as build job.
3. At Build Environment -> Use secret text(s) or file(s) -> Varialble: DEPLOY_KEY -> Upload a secret file (id_rsa PRIVATE key)
   
   
4. Use the following shell script template:

# Prepare bundler
gem install rubygems-bundler
bundle install

# Setting up ssh-agent for capistrano
eval `ssh-agent`
ssh-add $DEPLOY_KEY

# Deploy scripts here
bundle exec cap staging deploy

# Kill ssh-agent
kill $SSH_AGENT_PID

Tips

1. You can create new job based on old ones.
2. If you want Jenkins to integrate with GitHub:
   • Go to https://github.com/settings/tokens to generate your token
   • Manage Jenkins -> Configure System
   • GitHub -> Add GitHub Server
   • Credentials: Secret Text -> Input your token here
     
     
3. Project configuration tips:
   • Build Triggers -> Build when a change is pushed to GitHub
   • Post-build Actions: Set status for GitHub commit (need to have token set) -> Status Result: One of default.
     
     
4. If you want to bypass CI in commit message like [ci skip], install this plugin ci-skip

Troubleshooting

1. If any packages are needed to be installed, email: joshua841025@gmail.com or fork my Dockerfile.