1. What is Monit and M/Monit?

Monit is a monitoring system for primarily *nix-systems. 

2. Licensing

M/Monit requires a license to run more than the 30-day trial.
Monit does not require any license.

3. Admin login to M/Monit

The admin login details are available only for linux admins.

4. M/Monit install location

M/Monit is installed in /usr/local/mmonit. Each new version is installed in a separate folder in /usr/local/mmonit.

5. Monit

M/Monit depends on data being sent from the monit daemon from each computer you want to monitor.
Monit is installable from the regular repos, eg EPEL.
# yum install monit
Some settings needs to be set after installation.
For CentOS 6.x, please see /etc/monit.conf for an example.
For CentOS 7.x, please see /etc/monitrc an example.
There are two places that need to be uncommented and edited:
## Send status and events to M/Monit (for more informations about M/Monit
## see http://mmonit.com/). By default Monit registers credentials with
## M/Monit so M/Monit can smoothly communicate back to Monit and you don't
## have to register Monit credentials manually in M/Monit. It is possible to
## disable credential registration using the commented out option below.
## Though, if safety is a concern we recommend instead using https when
## communicating with M/Monit and send credentials encrypted.

set mmonit http://adminuid:adminpassword@ and register without credentials # Don't register credentials
## Monit has an embedded HTTP interface which can be used to view status of
## services monitored and manage services from a web interface. The HTTP
## interface is also required if you want to issue Monit commands from the
## command line, such as 'monit status' or 'monit restart service' The reason
## for this is that the Monit client uses the HTTP interface to send these
## commands to a running Monit daemon. See the Monit Wiki if you want to
## enable SSL for the HTTP interface.

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 @users readonly


6. Allowing monit and M/Monit through the firewall

Example rules for CentOS 6.x: 

# Allow all traffic to and from monit
iptables -A INPUT -p tcp -s -j ACCEPT
iptables -A OUTPUT -p tcp -d -j ACCEPT

 Example rules for CentOS 7.x: 

# firewall-cmd --add-port=2812/tcp --permanent


7. Restarting daemons after editing iptables and monit

Do not forget to save and restart the daemons after each re-configuration! 

For CentOS 6.x:

# service iptables restart
# service monit restart

 For CentOS 7.x:

# systemctl restart firewalld 
# systemctl enable monit        #Ensures that the monit daemon autostarts after reboot
# systemctl restart monit 

 The M/Monit daemon is started and stopped using the below commands on cyndane2.

# Latest is a symbolic link pointing to the latest installed actual version of M/Monit.
/usr/local/mmonit/latest/bin >> /usr/local/mmonit/mmonit-3.7.1
# /usr/local/mmonit/latest/bin/mmonit start
# /usr/local/mmonit/latest/bin/mmonit stop


8. M/Monit database

M/Monit is using SQLite as the database for saving clients, groups and other settings.

It is located in /usr/local/mmonit/.


9. M/Monit documentation

M/Monit documentation is available on https://mmonit.com/documentation/


10. Sources