For this article I used the chapter Setting Up A Development Environment in Agile Web Development with Rails, version 2.0, plus these two articles.

• Time For A Grown-Up Server: Rails, Mongrel, Apache, Capistrano and You
• Using Capistrano with Rails

Capistrano working together with Mongrel allows you to deploy and restart Mongrel clusters quite nicely.

Configure Mongrel Cluster

First you need to configure a Mongrel cluster. Here is an example that creates three Mongrel instances starting at port 8000, listening on the local interface, 127.0.0.1.

$  mongrel_rails cluster::configure -N 3 -p 8000 -e production -a 127.0.0.1 \
   -c /usr/local/rails/production/current \
   -C /usr/local/rail/production/current/config/mongrel_cluster.yml

Here is how the created file looks like.

---
cwd: /usr/local/rails/production/current
log_file: log/mongrel.log
port: "8000"
environment: production
address: 127.0.0.1
pid_file: tmp/pids/mongrel.pid
servers: 3

Note that for testing purposes you should comment out the address line.

#address: 127.0.0.1

We specified listening only on the local interface for security purposes but for testing the cluster we need to access it directly via its remote IP address.

Setup Capistrano

Next you create a stub Capfile and config/deploy.rb.

$ capify .

Now you can get a list of all the tasks that are available and there quite a few.

$ cap -T

Next modify config/deploy.rb like in this example.

require 'mongrel_cluster/recipes'

set :application, "foobook"
set :repository, "http://example.com/svn/foo/trunk/foobook"

role :web, "192.168.3.17"
role :app, "192.168.3.17"
role :db,  "192.168.3.117", :primary => true

set :deploy_to, "/usr/local/rails/production"
set :mongrel_conf, "#{current_path}/config/mongrel_cluster.yml"
set :svn_user, "fkim"
set :svn_password, "fkim"
#set :user, "root"            # defaults to the currently logged in user
set :scm, :subversion         # defaults to :subversion
set :svn, "/usr/bin/svn"      # defaults to searching the PATH

Deploy using Capistrano

Now run setup which will create the directories remotely.

$ cap deploy:setup

Check dependencies.

$ cap -q deploy:check

Deploy for the first time.

$ cap deploy:cold

Everytime after you can deploy like this.

$ cap deploy

Starting and Stopping Mongrel using Capistrano

If you want to just start the mongrel cluster.

$ cap mongrel:cluster:start

If you want to just stop the mongrel cluster.

$ cap mongrel:cluster:stop

And that’s it.

Not that bad at all. Starting and stopping mongrel was the biggest issue for me. I realized that I did not need to create the spin script as suggested in the Using Capistrano with Rails article. If the mongrel configuration is correct then Capistrano will correctly start and stop it and you can use the above cap commands to test it.