Install Munin Monitoring in Ubuntu 11.10 Oneiric with nginx

Munin is a networked resource monitoring tool that can help analyze resource trends and “what just happened to kill our performance?” problems. It is designed to be very plug and play. A default installation provides a lot of graphs with almost no work.

In Norse mythology Hugin and Munin are the ravens of the god king Odin. They flew all over Midgard for him, seeing and remembering, and later telling him. “Munin” means “memory“.

Install Munin by issuing as root

apt-get install munin munin-node munin-plugins-extra

Activate as many plugins as required, there is more than 230 plugins!

Here are some I did add to the list of already activated one. Some were added for obvious reason like mysql, nginx and fail2ban to monitor SSH brute force attempt…

cd /etc/munin/plugins/
ln -s /usr/share/munin/plugins/nginx_status nginx_status
ln -s /usr/share/munin/plugins/nginx_request nginx_request
ln -s /usr/share/munin/plugins/mysql_ mysql
ln -s /usr/share/munin/plugins/mysql_queries mysql_queries
ln -s /usr/share/munin/plugins/fail2ban fail2ban

Fail2Ban require root access to the socket of fail2ban, so edit munin-node

vi /etc/munin/plugin-conf.d/munin-node

And append at the end

[fail2ban*]
user root

Restart Munin-node and force the munin-cron process to run the initial html reports or wait 5 minutes…

/etc/init.d/munin-node restart
sudo -u munin munin-cron

Add to the crontab of the user Munin the command to run Munin every 5 minutes:

sudo -u munin crontab –e
*/5 * * * *     /usr/bin/munin-cron

Protect the server host where Munin will output its reports

htpasswd -c /etc/nginx/.htpasswd username

Now add a new site to nginx

vi /etc/nginx/sites-enabled/waltercedric

And put at least the following inside

server {
listen       80;
server_name  munin.acme.com;
root /var/cache/munin/www;
 location / {
    expires off;
    auth_basic "Munin";
    auth_basic_user_file /etc/nginx/.htpasswd;
 }
}

And reload nginx configuration with service nginx reload

You can now point any browser to http://munin.acme.com