CODEWITHSUNDEEP
ruby-on-railscapistrano
junda
junda

Reputation: 51

deploy similar ruby on rails code to multiple server

I have a rails app looking good on my localhost. Now I want to deploy it to multiple server (one load balancer, and two application server to be exact, with possible increase in the future), and somehow I'm lost. This would be my first time deploying a web by myself, so I'm sorry for my lack of knowledge.

I want all application server to run exactly same code. And when I create a new content, I want the new content to be stored on each server's database instance (MySQL). So when I took down one server for maintenance and updating, the rest of the server could serve users with exact same content. I've read that capistrano could help me with this, but somehow I managed to get lost in learning how to do this. So, how should I proceed from here? How should the capistrano recipe look like, and do I have to tweak database.yml in my rails also?

Thank you very much for help.

Upvotes: 1

Views: 1918

Answers (1)

Oscar Barrett
Oscar Barrett

Reputation: 3265

You can use roles to deploy the same application to multiple servers. Assuming you're using the multistage extension, define the roles in production.rb:

server1 = 'appserver1.tld'
server2 = 'appserver2.tld'
server3 = 'webserver1.tld'

role :app, server1, server2
role :web, server3

The web server will run on servers specified by the :web role.

The app layer will run on servers specified by the :app role.

If you run migrations or other DB operations during deploy, you should also specify a server under the :db role. For example:

role :db, 'dbserver.tld', :primary => true

You may have multiple DB servers, but by specifying one as the primary server capistrano will only run DB operations on that server.

In your deploy.rb, you can also create tasks that run only for certain roles. For example:

task :restart, :roles => :app, :except => { :no_release => true } do
    run "touch #{current_path}/tmp/restart.txt"
end

In the above example, :except => { :no_release => true } means that it will only run if at least one release exists on the server being deployed to.

This wiki article may be of further help to you.

Upvotes: 3

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