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TOTD #11: Setup Mongrel cluster for JRuby-on-Rails applications on Unix

This TOTD explains the steps to setup a Mongrel cluster for JRuby-on-Rails applications on a Unix flavor operating system. These instructions do NOT work on Windows. A similar post for Windows is cooking and will be posted when ready.

1. Download JRuby 1.0.1 and unzip the bundle (say JRUBY_HOME).

   1. For convenience, include JRUBY_HOME/bin to your PATH.

2. Install the required RubyGems

   1. Install Rails as shown below:
      
      jruby -S gem install rails --version 1.2.3 --include-dependencies --no-ri --no-rdoc
Bulk updating Gem source index for: http://gems.rubyforge.org
Successfully installed rails-1.2.3
Successfully installed activesupport-1.4.2
Successfully installed activerecord-1.15.3
Successfully installed actionpack-1.13.3
Successfully installed actionmailer-1.3.3
Successfully installed actionwebservice-1.2.3

   2. Before installing Mongrel, install the pre-requisite Gems as shown below (see discussion here):
      
      jruby -S gem install gem_plugin --no-ri --no-rdoc
Successfully installed gem_plugin-0.2.2
      
      and another one:
      
      jruby -S gem install cgi_multipart_eof_fix --no-ri --no-rdoc
Successfully installed cgi_multipart_eof_fix-2.3

   3. Mongrel cannot be installed as a gem on JRuby yet. So download Mongrel gem and install it as shown below:
      
      jruby -S gem install mongrel-1.0.1-jruby.gem --no-ri --no-rdoc
Successfully installed mongrel, version 1.0.1
      
      Make sure to invoke the command from the directory where the gem is downloaded.

   4. Install Mongrel cluster. mongrel_cluster does not work with JRuby and so instead mongrel_jcluster needs to be installed as shown below:
      
      jruby -S gem install mongrel_jcluster --include-dependencies --no-ri --no-rdoc
Successfully installed mongrel_jcluster-0.0.1

As mentioned here, mongrel_jcluster is still quite experimental and not guaranteed to work in any way but it worked for this post :)

3. Create a template application say in JRUBY_HOME/samples as shown below:
   
   /home/arung/testbed/jruby-1.0.1/samples/rails 1954 $ ../../bin/jruby -S rails hello
      create
      create  app/controllers
      create  app/helpers
      create  app/models
      ...
      create  log/production.log
      create  log/development.log
      create  log/test.log

4. Start Mongrel as shown below:
   
   cd hello
/home/arung/testbed/jruby-1.0.1/samples/rails/hello $ ../../../bin/jruby script/server
=> Booting Mongrel (use 'script/server webrick' to force WEBrick)
=> Rails application starting on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
** Ruby version is not up-to-date; loading cgi_multipart_eof_fix
** Starting Mongrel listening at 0.0.0.0:3000
** Starting Rails with development environment...
** Rails loaded.
** Loading any Rails specific GemPlugins
** Signals ready.  TERM => stop.  USR2 => restart.  INT => stop (no restart).
** Rails signals registered.  HUP => reload (without restart).  It might not work well.
** Mongrel available at 0.0.0.0:3000
** Use CTRL-C to stop.
   
   The application is now available at http://localhost:3000. Hit Ctrl-C to stop Mongrel as shown below:
   
   ^C** INT signal received.
Exiting
/home/arung/testbed/jruby-1.0.1/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:498:in
`require': Mongrel::StopServer (Mongrel::StopServer)
        from /home/arung/testbed/jruby-1.0.1/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/commands/server.rb:39
        from /home/arung/testbed/jruby-1.0.1/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require'
        from /home/arung/testbed/jruby-1.0.1/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require'
        from :1

5. Configure and Start Mongrel cluster

   1. Configure Mongrel cluster as shown below:
      
      /home/arung/testbed/jruby-1.0.1/samples/rails/hello $ ../../../bin/jruby -S mongrel_rails jcluster::configure -p 8000 -N 2
Writing configuration file to config/mongrel_cluster.yml.
      
      This starts a cluster of 2 Mongrels (identified by -N 2) assigning ports in the ascending order starting at 8000 (identified by -p 8000).

   2. Start Mongrel cluster as shown below:
      
      /home/arung/testbed/jruby-1.0.1/samples/rails/hello $ ../../../bin/jruby -S mongrel_rails jcluster::start
** Ruby version is not up-to-date; loading cgi_multipart_eof_fix
Starting JRuby server...
Starting 2 Mongrel servers...

6. Now your application is available on http://localhost:8000 and http://localhost:8001. All the logs (for all the instances) are available in log/development.log.

7. The cluster can be stopped as shown below:
   
   /home/arung/testbed/jruby-1.0.1/samples/rails/hello $ ../../../bin/jruby -S mongrel_rails jcluster::stop
** Ruby version is not up-to-date; loading cgi_multipart_eof_fix
Stopping 2 Mongrel servers...

A follow up post will show how to front-end this cluster of Mongrels with a light-weight HTTP server.

An alternative to this behemoth configuration is to create a Web ARchive (WAR) of your JRuby-on-Rails application and deploy on GlassFish. A complete screencast of how this can be achieved using NetBeans IDE is shown here. A comprehensive list of JRuby on GlassFish documentation is available here.

Technorati: totd rubyonrails jruby mongrel unix jrubyonglassfish glassfish netbeans ruby

Posted by Arun Gupta in web2.0  |  Comments[5]