Monitoring the Rails server with Munin

By AKM

May 13, 2010

Munin is an open source alternate for monitoring your application servers

Install Munin

sudo apt-get install munin munin-node

For more detailed steps see here.

Install the gems on the server

sudo gem install request-log-analyzer munin-plugins-rails

Add passenger plugins:

sudo request-log-analyzer-munin install

Add application log monitoring

sudo request-log-analyzer-munin add <app_name> <path_to_log_file>

app_name: this will be the prefix for the graphs and the munin plugins so it should be a valid identifier i.e should be alphanumeric.
path_to_log_file: the path to the application log file. request-log-analyzer will run on this file.

Note that the default config files assume executables are in /usr/local/bin. In case, they are in /usr/bin, run the following script on the terminal to create soft links.

for exe in ruby request-log-analyzer passenger-status passenger-memory-stats do
    ln -s /usr/bin/$exe /usr/local/bin/$exe
done

Restart Munin:

sudo service munin-node restart

Munin Dashboard

Ideally, you would like to access munin dashboard from your browser. Here are the steps:

create config file /etc/apache2/sites-available/munin with following content

<VirtualHost *:80> 
    ServerName munin.yourserver.com 
    DocumentRoot /var/cache/munin/www 
    <Directory "/var/cache/munin/www"> 
        Options -Indexes FollowSymLinks 
        AllowOverride AuthConfig FileInfo 
        Order allow,deny 
        Allow from all 
    </Directory>
</VirtualHost>

# Enable the site
ln -s /etc/apache2/sites-available/munin /etc/apache2/sites-enabled/munin

# Restart Apache
apache2ctl graceful

# Set up subdomain:
Make sure the DNS is set up properly. Point the sudomain munin.yourserver.com to your server's IP address.

Info

Plugins are installed in: /etc/munin/plugins
Plugin configurations are in: /etc/munin/plugin-conf.d
Log files are: /var/log/munin/munin-node.log

References

http://www.alfajango.com/blog/how-to-monitor-your-railspassenger-app-with-munin
https://github.com/barttenbrinke/munin-plugins-rails

Alternatives

In case, you would like to explore some other options:

Rails
Linux