Nagios removed by autoremove

Question

One of our servers autoremoved Nagios while doing a monthly cleanup. History file shows it listed for removal.

Is it possible to determine why it was marked for removal?

Answer 1

There is no log detailing apt's logic. But the logic is so simple that a log isn't needed. There are only two criteria to make a package eligible for autoremoval.

1) It's apt-marked 'auto'

2) No installed package that is apt-marked 'manual' needs it as a dependency.

If you want to keep a specific package, then change #1 using the apt-mark command. You don't need to mark every dependency - those will be kept by #2.

Example: sudo apt-mark manual name_of_my_package