Server Monitoring with Monit Tutorial

As you sit down for a lovely Christmas dinner with family and friends, your phone rings. The frantic client is on the line shouting that the server just went down. Don't you wish you had a helpful program that automatically monitors and restarts the servers automatically.

Monit is an open source process supervision program that monitoring your server processes and restarts failed services. It is easy to setup and relatively painless to use.

Here is a quick tutorial to configure Monit to monitor Apache and MySQL servers.

$ sudo apt-get install monit 

# Monit Configuration settings
$ sudo nano /etc/monit/monitrc 
  set daemon 60 
  set logfile /var/log/monit.log
  set idfile /var/lib/monit/id
  set statefile /var/lib/monit/state
  set eventqueue
  set httpd port 2812 and
   use address localhost
   allow localhost
   include /etc/monit/conf.d/*

# Create Apache2 monitoring file 
$ sudo nano /etc/monit/conf.d/apache2 
check process apache with pidfile /run/apache2.pid
    start program = "/etc/init.d/apache2 start" 
    stop program  = "/etc/init.d/apache2 stop"


# Create  MySQL monitoring file
$ sudo nano /etc/monit/conf.d/mysql 
check process mysqld with pidfile /var/run/mysqld/mysqld.pid
    start program = "/etc/init.d/mysql start"
    stop program = "/etc/init.d/mysql stop"

# Check monit configuration for syntax errors 
$ sudo monit -t 


# Start Monit daemon
sudo service monit start 

# Check Monit status 
$ sudo monit status
The Monit daemon 5.3.2 uptime: 4m 

Process 'mysqld'
  status                            Running
  monitoring status                 Monitored
  pid                               2676
  parent pid                        1
  uptime                            4d 8h 1m 
  children                          0
  memory kilobytes                  256380
  memory kilobytes total            256380
  memory percent                    12.5%
  memory percent total              12.5%
  cpu percent                       0.0%
  cpu percent total                 0.0%
  data collected                    Wed, 10 Dec 2014 08:43:13

Process 'apache'
  status                            Running
  monitoring status                 Monitored
  pid                               4230
  parent pid                        1
  uptime                            4d 8h 1m 
  children                          27
  memory kilobytes                  11556
  memory kilobytes total            391484
  memory percent                    0.5%
  memory percent total              19.1%
  cpu percent                       0.0%
  cpu percent total                 0.0%
  data collected                    Wed, 10 Dec 2014 08:43:13

System 'system_foobar.org'
  status                            Running
  monitoring status                 Monitored
  load average                      [0.00] [0.01] [0.05]
  cpu                               0.0%us 0.0%sy 0.0%wa
  memory usage                      666736 kB [32.6%]
  swap usage                        140 kB [0.0%]
  data collected                    Wed, 10 Dec 2014 08:43:1

That's all folks! Now you have a wonderful Christmas!