Munin is an excellent system monitoring tool similar to RRD tool which will give you ample information about system performance in multiple fronts like disk, network, process, system and users. These are some of the default properties Munin monitors.
How Munin works?
Munin works in a client-server model. Munin server process on main server try to collect data from client daemon which is running locally(Munin can monitor its own resources) or from remote client(Munin can monitor hundreds of machines) and displays them in graphs on its web interface.
Configuring Munin in nutshell
This is of two steps as we have to configure both server and client.
1)Install Munin server package and configure it so that it get data from clients.
2)Configure Munin client so that server will connect to client daemon for data collocation.
Install Munin server in Linux
Munin server installation on Ubuntu/Debian based machines
# apt-get install munin apache2
Munin server installation on Redhat/Centos based machines. Make sure that youenable EPEL repo before installing Munin on Redhat based machines as by default Redhat based machines do not have Munin in their repos.
# yum install munin httpd
Configuring Munin server in Linux
Below are the steps we have to do in order to bring server up.
1) Add host details which need monitoring in /etc/munin/munin.conf
2) Configure apache web server to include munin details.
3) Create Username and password for web interface
4) Restart apache server
Step 1: Add hosts entry in this file in /etc/munin/munin.conf. Go to end of the file and a client to monitor. Here in this example, I added my DB server and its IP address to monitor
Save the file and exit.
Step 2: Edit/create munin.conf file in /etc/apache2/conf.d folder to include Munin Apache related configs. In another note, by default other Munin web related configs are kept in /var/www/munin folder.
# vim /etc/apache2/conf.d/munin.conf
Alias /munin /var/www/munin
Allow from localhost 127.0.0.0/8 ::1
Options ExecCGI FollowSymlinks
AddHandler cgi-script .cgi
AuthName “Munin stats”
Save the file and exit
Step 3: Now create a username and password for viewing muning graphs:
# htpasswd -c /etc/munin/munin-htpasswd munin
Note: For Redhat/Centos machines replace “apache2” with “httpd” in each path to access your config files.
Step 4: Restart Apache server so that Munin configurations are picked-up by Apache.
# service apache2 restart
# service httpd restart
# systemctl restart httpd
Install and configure Munin client in Linux
Step 1: Install Munin client in Linux
# apt-get install munin-node
# yum install munin-node
Note: If you want to monitor your Munin server, then you have to install munin-node on that as well.
Step 2: Configure client by editing munin-node.conf file.
# Which address to bind to;
# And which port
Note: 10.10.20.20 is my Munin server and it connections to 4949 port on client to get its data.
Step 3: Restart munin-node on client
# service munin-node restart
# service munin-node restart
# systemctl restart munin-node
check if you are able to connect client from server on 4949 port, other wise you have to open that port on client machine.
telnet db.linuxnix.com 4949
Accessing Munin web interface
Hope this helps to configure basic Munin server.