After having used Nagios for many years, I tried M/Monit, and it is mostly what I want, but still it lacks the option to customize the format of the notification emails sent by M/Monit, which makes it unusable.
I have checked https://alternativeto.net/software/nagios/ , but they are not simple at all.
Question
Does there exist a super simple alternative to Nagios (or M/Monit)? All I really need is something central that can send out an email when NRPE or Monit gives an alert or they aren't heard from in X seconds.
It doesn't even need to have a web interface, some sort of command line is fine.