Munin is a server monitoring and status application that provides two components:
Munin can provide status and monitoring for any configuration from a single VPS to an entire datacenter of machines.
The following guide assumes you're logged in as root and running CentOS 6 x64 on Vultr. This guide should be applicable to CentOS 7 too.
You will require two servers.
Note that you can also monitor Server A, if desired.
Follow these steps on Server A.
First, install Apache to serve our Munin server status page, as well as Munin itself.
yum install httpd munin
Install nano if you're not comfortable in vi.
yum install nano
It's time to edit the Munin configuration to add monitoring of our additional servers, as by default Munin only monitors the local machine. Run the following.
At the bottom, append the following where 192.168.10.2 is replaced with the IP address of Server B, and "serverb" is replaced with a descriptive hostname.
[serverb] address 192.168.10.2 use_node_name yes
Additional servers to be monitored can be added in the same manner.
By default, Munin is not secured with a password. To setup a password, run the following:
... and enter a password to secure your Munin installation.
The username is munin.
Start Apache and Munin-node.
service start httpd service start munin-node
You will now be able to login to
http://[SERVER_A_IP]/munin with the username munin and the password you have just specified.
Continue below for setting up munin-node on additional machines and configuring munin-node plugins.
The following can be applied to Server A, Server B, and as many additional servers as needed.
Install munin-node if it is not already installed.
yum install munin-node
Append a new line with the IP address of Server A. The address must be in the format of a regular expression. Replace "192.168.10.1" the IP address of Server A.
At this point, you can start munin-node.
service munin-node restart
Server B's status will be visible on your Munin status page at
http://[SERVER_A_IP]/munin within a few minutes time.
munin-node comes packaged with a wide variety of plugins.
To browse the available plugins:
cd /usr/share/munin/plugins/ ls
All plugins can be enabled by creating a symbolic link to it in the
/etc/munin/plugins folder. For example, to enable the Apache status plugins, run the following commands:
ln -s /usr/share/munin/plugins/apache_accesses /etc/munin/plugins/apache_accesses ln -s /usr/share/munin/plugins/apache_processes /etc/munin/plugins/apache_processes ln -s /usr/share/munin/plugins/apache_processes /etc/munin/plugins/apache_volume
... then restart munin-node.
service munin-node restart
Wait a few minutes and your status will be available on your master server.