Monit

is a utility for managing and monitoring processes, programs, files, directories and filesystems on a UNIX system.

Configuration
Config file of monit resides in. And there is a item to specify a config directory. Uncomment if needed.

Users
Users added to the monit or users group will be able to manipulate monit through the web interface.

OpenRC
To start the service at boot.

To start the service immediately.

Pidfile Check
monit relies on the pidfile convention, it can only monitor background daemons. For daemons that do not create a pidfile, a trick is needed.

pidfile approach is intrinsically broken for monitforing process. Monit can overcome this by checking the pidfile frequently enough to be reliable, though.

Monitoring Monit
This hourly cron script will check to make sure monit has not crashed. As this uses pgrep, make sure to not name it monit.

Squid Memory Alert
is a caching proxy that is memory hungry. It can control its memory consumption by itself in the configuration file, while we can make an redundent check here.

CLI Interface
We can run monit foreground and see the effect.

Web Interface
Navigate to http://localhost:2812/ & login using your edited configuration line or admin / monit if you have not changed it yet.