Monit is a small Open Source utility for managing and monitoring Unix systems.
This article explains the details to install Monit on Ubuntu.
Step1: Login to the server via ssh as root.
Step2: Install Monit.
#apt install monit
Step3: Start Monit service.
#systemctl start monit
Step4: Enable Monit service to run in startup.
#systemctl enable monit
Please note that Monit also providing a web interface which is accessible through the following url.
Where IP need to be replaced with the ipaddress of the server.