Effective Rails Deployment01 Apr 2016
Capistrano has been an excellent tool for years to deploy simple or multi-stage complex applications to remote servers. However the rise of PASS like Heroku, Dokku, I got in mind to use some automatic orchestration framework.
I looked over Chef, Puppet, SaltStack and Ansible on a weekend and decided to go with ansible since it looked easiest to get hands dirty and have great documentation. After some initial hicups I was able to deploy some of our inhouse applications on EC2 and introduced it to my coworkers at codecrux.
Since then, we use ansible to configure and manage remote server, and also configure our local development environment running on top of Virtualbox with vagrant.
Ansible uses YAML for configuration and for actual commands it has less flexibility compared to capistrano which uses Ruby DSL, but at the same time helps you to keep your playbooks simple. ansible also extremely good with orchestration and rolling deployments. We were able to keep a homogenous command set and duplicate most of Capistrano’s features in very small amount of code.
Let’s take an example to deploy lobster.rs. Here is how we did it -
First of all you need to define required variables in a yaml file for ansible to pick them up.
--- app_name: lobsters rails_env: production git_url: email@example.com:jcs/lobsters.git git_version: master app_path: '/' shared_path: '/shared' releases_path: '/releases' current_release_path: '/current' app_public_path: "/public" app_config_path: "/config" app_temp_path: "/tmp" app_logs_path: "/log" keep_releases: 5
You should also define your remote host in ansible inventory/host file like
[production] lobsters.dev ## replace with your domain name
Now when we have configuration we can create the actual playbook for doing capistrano-style deployments. Create
--- - hosts: all tasks: - set_fact: this_release_ts= - set_fact: this_release_path=/ - debug: msg='New release path ' - name: Create new release dir file: path= state=directory - name: Update code git: repo= dest= version= accept_hostkey=yes register: git - debug: msg='Updated repo from to ' - name: Symlink shared files file: src=/ dest=/ state=link force=yes with_items: - config/database.yml - config/secrets.yml - config/unicorn.rb - log - tmp - vendor/bundle - name: Install bundle command: 'bundle install --deployment --without="development test"' args: chdir: '' - name: Precompile assets command: rake assets:precompile chdir= environment: RAILS_ENV: '' - name: Migrate database command: rake db:migrate chdir= environment: RAILS_ENV: '' - name: Symlink new release file: src= dest= state=link force=yes - name: Restart unicorn command: sudo restart - name: Cleanup shell: "ls -1t |tail -n +|xargs rm -rf" args: chdir: ''
Once everything is set up, you can run the following command to deploy:
ansible-playbook -u railsbox -i production deploy.yml