I found Munin much more useful than Nagios for monitoring a single server. This guide will show you how to set up a single Munin instance that generates pretty graphs with cron and is accessible via Munin’s web interface.
Get Munin’s dependencies
You will need EPEL, a webserver (I’ll use Apache here) and some Munin packages.
Get the latest EPEL repo from here and install. example:
# rpm -i http://mirrors.ptd.net/epel/6/i386/epel-release-6-8.noarch.rpm
# yum install munin munin-node httpd
Start Munin Service and Enable on boot
# service munin-node start # service httpd start # chkconfig munin-node on # chkconfig httpd on
Configure Web Interface
Setup a user and password to access the web interface.
# htpasswd /etc/munin/munin-htpasswd <INSERT A USER NAME HERE>
Navigate to web interface: http://<server ip>/munin
If you don’t see the UI below, but instead see a directory listing, give Munin a few minutes to generate data. By default it will generate graphs every 5 minutes. I usually edit /etc/cron.d/munin such that graphs are generated every hour as I use it more for historical purposes and if I need immediate insight I just use htop.
Some example graphs: