joshua5201 / ci-jenkins-docker-rails

Installation Process for rails test and deploy running inside dockers on jenkins CI

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: [e-mail] or fork my Dockerfile.