Monit is a opensource process tool for Linux operating system which helps you to monitor system process using web browser and also when ever requires it automatically do the maintenance or repair of particular process in such a way that it can be brought back online. It can also used for managing and monitoring of programs, files, directories, and devices for timestamps changes, checksum changes, or size changes; not limited to perform various TCP/IP network checks, protocol checks, and can utilize SSL for such checks.
It logs to its own log file and notifies the user via customizable messages, this guide will help you to set up monit on CentOS / RHEL.
[root@server ~]# rpm -Uvh http://ftp.jaist.ac.jp/pub/Linux/Fedora/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
Install the Monit.
[root@server ~]# yum -y install monit
Start monit by using the following command.
[root@server ~]# monit
Check the monit status.
[root@server ~]# monit status The Monit daemon 5.6 uptime: 0m System 'server.itzgeek.com' status Running monitoring status Monitored load average [0.14] [0.55] [0.49] cpu 0.0%us 0.0%sy 0.0%wa memory usage 390704 kB [20.8%] swap usage 0 kB [0.0%] data collected Wed, 23 Jul 2014 16:06:28
Monit config file is /etc/monit.conf, by default monit is set to check the services at interval of 1 min, this setting can be altered by changing.
[root@server ~]# vi /etc/monitrc set daemon 60
Alert cans be configured by.
Alert templates can be found in the configuration file itself.
Logs setting can be changed by using the following file.
[root@server ~]# vi /etc/monit.d/logging set logfile
Monit also provides a web interface to monitor and manage the configured services, by default monit listens on 2812 port but it needs to be setup. Open monit configuration file /etc/monit.conf.
[root@server ~]# vi /etc/monit.conf
Look for httpd port 2812, modify the following entries.
set httpd port 2812 and use address localhost # only accept connection from localhost allow localhost # allow localhost to connect to the server and allow admin:monit # require user 'admin' with password 'monit' allow @monit # allow users of group 'monit' to connect (rw) allow @users readonly # allow users of group 'users' to connect readonly
set httpd port 2812 allow 0.0.0.0/0.0.0.0 allow admin:monit
From the above settings, monit will listen on 2812; admin user will able to access the web interface from any network.
[root@server ~]# systemctl restart monit.service
Auto start Monit on start-up.
[root@server ~]# systemctl enable monit.service
Access the web interface by using http://your-ip-address:2812, use the username and password mentioned in the previous step. Monit home page will look like this.
Configuring services for monitoring:
Once the web interface is up, we can start to setup other services that you want to monitor; you can place the configuration files under /etc/monit.d/ directory.
Configure for sshd.
[root@server ~]# vi /etc/monit.d/sshdmonitor check process sshd with pidfile /var/run/sshd.pid start program "/usr/bin/systemctl start sshd.service" stop program "/usr/bin/systemctl stop sshd.service" if failed port 22 protocol ssh then restart
Configure for syslog.
[root@server ~]# vi /etc/monit.d/syslogmonitor check process syslogd with pidfile /var/run/syslogd.pid start program = "/usr/bin/systemctl start rsyslog.service" stop program = "/usr/bin/systemctl stop rsyslog.service"
Once configured, test the monit syntax
[root@server ~]# monit -t Control file syntax OK
Reload it, to take effect of changes.
[root@server ~]# monit reload
Access the web interface, you would find the new services that we configured earlier.
Test the Monitoring:
Now stop the syslog daemon.
[root@server ~]# /etc/init.d/rsyslog stop
Wait for 30 second, monit will start the syslog automatically. You can find it in monit log.
[root@server ~]# cat /var/log/monit [EDT Jul 23 16:28:04] error : 'syslogd' process is not running [EDT Jul 23 16:28:04] info : 'syslogd' trying to restart [EDT Jul 23 16:28:04] info : 'syslogd' start: /usr/bin/systemctl [EDT Jul 23 16:29:04] info : 'syslogd' process is running with pid 40440
That’s All, We have successfully configured Monit on CentOS 6 / RHEL 6. We welcome your feedback, please post your valuable comments below.