MONIT to monitor Linux server

Monit is a free open source and very useful tool that automatically monitors and manages server process, files,directories, checksums, permissions, filesystems and services like Apache, Nginx, MySQL, FTP, SSH, Sendmailand so on in a UNIX/Linux based systems and provides an excellent and helpful monitoring functionality to system administrators.The monit has user friendly web interface where you can directly view the system status and setup up processes using native HTTP(S) web server or via the command line interface.

Installing Moint for CentOS / Redhat / Fedora
-----------------------------------------------------------
yum install epel*
yum install monit
/etc/init.d/monit start
chkconfig monit on

# We can see logs from   tail -f /var/log/monit

## Config file

 vi /etc/monit.conf

** Can change those default settings

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'

----------- to

set httpd port 2812 and

    use address 203.190.X.X # only accept connection from server 203.190.X.X

    allow 203.190.X.0/21        # allow IP-Network to connect to the server and

    allow admin:tayab321      # require user 'admin' with password 'tayab321'

## Also can see in web format....

http://203.190.x.x:2812/
username: admin
password: tayab321

##########
Adding other services to Monit
-------------------------------------
# Adding HTTP service to Monitor
check process httpd with pidfile /var/run/httpd/httpd.pid
group apache
start program = "/etc/init.d/httpd start"
stop program = "/etc/init.d/httpd stop"
if failed host 203.190.X.X port 80
protocol http then restart
if 5 restarts within 5 cycles then timeout


# Adding MySQL service to Monitor
check process mysqld with pidfile /var/run/mysqld/mysqld.pid
group mysql
start program = "/etc/init.d/mysqld start"
stop program = "/etc/init.d/mysqld stop"
if failed host 203.190.10.90 port 3306 then restart
if 5 restarts within 5 cycles then timeout

# Adding MAIL POSTFIX service to Monitor

 check process postfix with pidfile /var/spool/postfix/pid/master.pid
    start program = "/etc/init.d/postfix start"
    stop program  = "/etc/init.d/postfix stop"
    if cpu > 60% for 2 cycles then alert
    if cpu > 80% for 5 cycles then restart
    if totalmem > 200.0 MB for 5 cycles then restart
    if children > 250 then restart
    if loadavg(5min) greater than 10 for 8 cycles then stop
    if failed host 203.190.x.x port 25 type tcp protocol smtp
       with timeout 15 seconds
      then alert
    if 3 restarts within 5 cycles then timeout

# Adding SSH service to Monitor
check process sshd with pidfile /var/run/sshd.pid
start program "/etc/init.d/sshd start"
stop program "/etc/init.d/sshd stop"
if failed host 203.190.X.X port 7707 protocol ssh then restart
if 5 restarts within 5 cycles then timeout

## To check monit syntax error in config file ::   monit -t

####### Enjoy this #tayab@tayabkhan.com###################################