rails symphonies

Note:

• A quick, down and dirty solution. There are more verbose resources on how to setup Mongrel Cluster and Apache. But this is also specifically tailored for Ubuntu Feisty Fawn.
• After installing mongrel, when executing ./script/server, you will not use Webrick anymore, but instead mongrel for development. You can still use Webrick if you want, but there isn’t much of a difference.

Plan of Attack

• Install, configure, and test Mongrel Cluster
• Install and test Apache
• Start Mongrel Cluster on boot

Installing Mongrel Cluster

sudo apt-get install ruby1.8-dev
sudo gem install -y mongrel mongrel_cluster

Note: If you see the following make sure you select the latest version of mongrel for ruby. In this case option 2.

Select which gem to install for your platform (i486-linux)
 1. mongrel 1.0.1 (mswin32)
 2. mongrel 1.0.1 (ruby)
 3. mongrel 1.0 (mswin32)
 4. mongrel 1.0 (ruby)
 5. Skip this gem
 6. Cancel installation
> 

Configuring Mongrel Cluster

Go to your Rails application directory and execute:

mongrel_rails cluster::configure -p 8000 -n 3

This allows mongrel to spawn 3 instance to handle the load. Each instance will open on port 8000, and succeeding. So that is 8000, 8001, and 8002.

Note: The mongrel_rails command has alot of options. Executing mongrel_rails -h will get you more information. All of these options can be changed later.

This will create the a mongrel_cluster configuration file in RAILS_ROOT/config/mongrel_cluster.yml

Testing Mongrel Cluster

In your Rails application directory, execute:

mongrel_rails cluster::start

Now open up http://localhost:8000/, http://localhost:8001/, and http://localhost:8002/ to ensure that your site is working perfectly fine.

Installing Apache

Enter into the Terminal:

sudo apt-get install apache2
sudo a2enmod proxy_balancer
sudo a2enmod proxy_http
sudo a2enmod rewrite

We will now create a common rails configuration file. As root open up /etc/apache2/mods-available/rails.conf , and insert the following:

  ServerName railsapp.com
  DocumentRoot /var/www/railsapp.com/public

  <Directory "/var/www/railsapp.com/public">
    Options FollowSymLinks
    AllowOverride None
    Order allow,deny
    Allow from all
  </Directory>

  RewriteEngine On

  # Uncomment for rewrite debugging
  #RewriteLog logs/railsappapp_rewrite_log
  #RewriteLogLevel 9 

  # Check for maintenance file and redirect all requests
  #  ( this is for use with Capistrano's disable_web task )
  RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
  RewriteCond %{SCRIPT_FILENAME} !maintenance.html
  RewriteRule ^.*$ /system/maintenance.html [L]

  # Rewrite index to check for static
  RewriteRule ^/$ /index.html [QSA] 

  # Rewrite to check for Rails cached page
  RewriteRule ^([^.]+)$ $1.html [QSA]

  # Redirect all non-static requests to cluster
  RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f
  RewriteRule ^/(.*)$ balancer://mongrel_cluster%{REQUEST_URI} [P,QSA,L]

  # Deflate
  AddOutputFilterByType DEFLATE text/html text/plain text/css
  # ... text/xml application/xml application/xhtml+xml text/javascript
  BrowserMatch ^Mozilla/4 gzip-only-text/html
  BrowserMatch ^Mozilla/4.0[678] no-gzip
  BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

  # Uncomment for deflate debugging
  #DeflateFilterNote Input input_info
  #DeflateFilterNote Output output_info
  #DeflateFilterNote Ratio ratio_info
  #LogFormat '"%r" %{output_info}n/%{input_info}n (%{ratio_info}n%%)' deflate
  #CustomLog logs/myapp_deflate_log deflate

Now we’ll set up the virtual host for our site railsapp.com For the last time as root open up /etc/apache2/sites-available/railsapp and insert the following:

Listen 8080
<VirtualHost *:8080>
  <Location />
    SetHandler balancer-manager
    Deny from all
    Allow from localhost
  </Location>
</VirtualHost>

<Proxy balancer://mongrel_cluster>
  BalancerMember http://127.0.0.1:8000
  BalancerMember http://127.0.0.1:8001
  BalancerMember http://127.0.0.1:8002
</Proxy>

<VirtualHost *:80>
  Include /etc/apache2/mods-available/rails.conf
  ErrorLog /var/log/apache2/rails_errors_log
  CustomLog /var/log/apache2/rails combined
</VirtualHost>

The first VirtualHost enables a front end for load balancing, available only to localhost on port 7999.
The second VirtualHost is our rails application. Notice how it is pulling in our default configuration (/etc/apache2/mods-available/rails.conf ). If you want to make changes you can specify it here. Need to specify a ServerName directive? Put it in here.

Lets enable the virtual host

sudo a2ensite railsapp

and restart Apache.

sudo /etc/init.d/apache2 restart

Now pull up your the domain you entered and your Rails application should load!

Note: If you can’t seem to access your site, its because the default virtual host has a higher precedence. Execute sudo a2dissite default . Similarly ensure that you are access your site via the domain you specified in the ServerName directive. In this case railsapp.com

If everything is work, you are on your way to more production based hosting solution.

Start Mongrel Cluster on Boot

Create mongrel_cluster conf directory (/etc/mongrel_cluster).

sudo mkdir /etc/mongrel_cluster

In the Mongrel Cluster gem, there is an init.d script you need to copy.

sudo cp /usr/lib/ruby/gems/1.8/gems/mongrel_cluster-0.2.1/resources/mongrel_cluster/mongrel_cluster /etc/init.d

Now let’s make the script executable.

sudo chmod +x /etc/init.d/mongrel_cluster

Now we need to add th init.d script to startup.
On Ubuntu:

sudo update-rc.d mongrel_cluster defaults

On RHEL/CentOS:

/sbin/chkconfig --level 345 mongrel_cluster on

Now create a symbolic link from RAILS_ROOT/config/mongrel_cluster.yml to a file in /etc/mongrel_cluster:

sudo ln -s /path/to/railsapp/config/mongrel_cluster.yml /etc/mongrel_cluster/railsapp

There you have it, you should be good to go!

Comments, bugs, problems, improvements

Have any bug, or problem? Leave a comment please.

Note:

• Once again, another quick, down and dirty solution. The guys behind mongrel have even written up how to set it up. This is a more condensed form, and suited for Ubuntu Feisty Fawn
• This is not the best solution for deployment, but it works if you want to do early testing/deployment for clients. An ideal solution would be utilizing capistrano and mongrel_cluster.
• After installing mongrel, when executing ./script/server, you will not use Webrick anymore, but instead mongrel for development. You can still use Webrick if you want, but there isn’t much of a difference.
• This requires the use of RubyGems. If you don’t have it installed, see my guide on setting up Rails using RubyGems.

Plan of Attack:

• Install and test Mongrel
• Install and test Apache
• Additional tips
  • Mongrel Service
  • Let Apache handle Requests for Static Files
• After thoughts

Install Mongrel

Enter into the Terminal:

sudo apt-get install ruby1.8-dev build-essential
sudo gem install -y mongrel

Note: If you see the following make sure you select the latest version of mongrel for ruby. In this case option 2.

Select which gem to install for your platform (i486-linux)
 1. mongrel 1.0.1 (mswin32)
 2. mongrel 1.0.1 (ruby)
 3. mongrel 1.0 (mswin32)
 4. mongrel 1.0 (ruby)
 5. Skip this gem
 6. Cancel installation
> 

Testing Mongrel

Go into your rails application root directory, and execute:

mongrel_rails start -p 8000

Open up your webbrowser and go to http://localhost:8000 and your application should load.
Note: mongrel_rails has alot of command line options. Executing mongrel_rails -h will get you more information.

Install Apache

Enter into the Terminal:

sudo apt-get install apache2
sudo a2enmod proxy_http

You’ll need change one file, specifically /etc/apache2/mods-available/proxy.conf
Look for the following line, it should be on line 11:

#Allow from .example.com

and replace it with:

Allow from all

Now as root, open up /etc/apache2/sites-available/railsapp .
Enter the following:

<VirtualHost *>
    ServerName railsapp.com
    ServerAlias www.railsapp.com

    ProxyPass / http://www.railsapp.com:8000/
    ProxyPassReverse / http://www.railsapp.com:8000/
    ProxyPreserveHost on
</VirtualHost>

Note: replace railsapp.com and www.railsapp.com with the actual domain/ip you will be using.

Enable the site and restart Apache

sudo a2ensite railsapp
sudo /etc/init.d/apache2 restart

Testing Apache

Fire up your browser. go to your site. It should be up and running.

Troubleshooting: If you get 403 forbidden, try removing the default site ( sudo a2dissite default) and change the (www.)railsapp.com setting to localhost. Optionally remove the lines containing ServerName and ServerAlias.

Additional Tips

• mongrel will need to be started up again, when you reboot your machine. We will cover setting it up as a service further down.
• mongrel can be given flags to run under a different environment. Perhaps for simple production sites.
• If two people try to access the site at the very same time, expect slight delays as only one intsance of mongrel is running.
• From now on mongrel will handle all requests. But this is a daft, as Apache can easily handle requests for static files: javascript, stylesheet and images. For solution view further down.
• If you want to deploy more than one rails application you’ll have to specify a ServerName, and ensure that mongrel is using different ports

Mongrel Service

There are some tips online on how to setup a mongrel service.

I like the second one by Bojan Mihelac as you can customize the default port, and the environment the mongrel instance is running in.

Here it is reproduced, make sure to install it in /etc/init.d/mongrel . Then you can start it by executing /etc/init.d/mongrel start . Works with start, stop, and restart.

Letting Apache handle Requests for Static Files

Include this into your railsapp file , inside the <VirtualHost>

ProxyPass /images !
ProxyPass /stylesheets !
#continue with other static files that should be served by apache

Alias /images /path/to/public/images
Alias /stylesheets /path/to/public/stylesheets
#continue with aliases for static content

Note: Ensure that the /path/to/public is readable by Apache

After thoughts

Using Mongrel for light sites is alright but it doesn’t scale well. Thats why we have mongrel_cluster to the recuse.