How to Install Monit on CentOS 7 – Monitoring Tool
How to Install Monit on CentOS 7
Monit is an opensource process monitoring tool for Linux operating system which helps you to monitor system process using the web browser and also whenever requires it automatically do the maintenance or repair of the particular process in such a way that it can be brought back online.
Monit can also use 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.
rpm -ivh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum -y install monit
(1/2): epel/x86_64/updateinfo | 927 kB 00:00:03 (2/2): epel/x86_64/primary | 3.5 MB 00:00:08 epel 12611/12611 Resolving Dependencies --> Running transaction check ---> Package monit.x86_64 0:5.25.1-1.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved =============================================================== Package Arch Version Repository Size =============================================================== Installing: monit x86_64 5.25.1-1.el7 epel 318 k Transaction Summary ================================================================ Install 1 Package Total download size: 318 k Installed size: 818 k Downloading packages: monit-5.25.1-1.el7.x86_64.rpm | 318 kB 00:00:01 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : monit-5.25.1-1.el7.x86_64 1/1 Verifying : monit-5.25.1-1.el7.x86_64 1/1 Installed:monit-5.25.1-1.el7.x86_64
Start monit by using the following command.
[root@server ~]# monit New Monit id: 8dc7a69b24bb98fa5526c9ff92c1592d Stored in '/root/.monit.id' Starting Monit 5.25.1 daemon with http interface at [localhost]:2812
Check the monit status.
[root@server ~]# monit status Monit 5.25.1 uptime: 0m System 'server.webhostingchennai.co.in' status OK monitoring status Monitored monitoring mode active on reboot start load average [0.08] [0.20] [0.19] cpu 0.0%us 0.0%sy 0.0%wa memory usage 109.1 MB [11.0%] swap usage 0 B [0.0%] uptime 18h 14m boot time Mon, 16 Jul 2018 13:49:47 data collected Tue, 17 Jul 2018 08:04:07 [root@server ~]#
/etc/monitrc the main configuration file of Monit. We can make changes to the Monit configuration file for our requirement.
By default, monit is set to check the services at an interval of 1 min. This setting can be altered by changing the below line.
set daemon 60
Alerts can be configured by.
set mailserver mx.webhostingchennai.local port 25
Monit Web Interface
Monit also provides a web interface for monitoring and managing the configured services. By default, monit listens on 2812 port, but it needs to be set up.
Open monit configuration file /etc/monitrc.
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.
systemctl restart monit
Auto-start Monit on start-up.
systemctl enable monit
Configuring in Firewall
Configure the firewall to allow access to Monit web interface, running on port 2812.
firewall-cmd --permanent --add-port=2812/tcp firewall-cmd --reload
Accessing web interface
Note: You can also use your customized port by editing “/etc/monitrc” and modify the “httpd port 2812” to “httpd port 3000”
Here, I’m using port 3000.
Use username admin and password monit to login.
Configure services with Monit for monitoring
Once the web interface is up, we can start to set up other services that you want to monitor. You can place the configuration files under /etc/monit.d/ directory.
Configuring SSH service.
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
Configuring for syslog.
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"
Configuring service for HTTP.
check process httpd with pidfile /var/run/httpd/httpd.pid start program "/usr/bin/systemctl start httpd.service" stop program "/usr/bin/systemctl stop httpd.service" if failed port 80 protocol http then restart
Once configured, test the monit syntax
Control file syntax OK
Reload it, to take effect of changes.
No access the web interface. You can see the new services that was configured.
Hope this article helps you, please share your comments to improve better.
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