Random Entropy is used for all kinds of things on a linux server. You need enough of it for pretty much everything to work - to be able to generate sufficiently random numbers. On a VPS, it can be difficult to have enough events to generate sufficient entropy. If a server does a lot of crypto functions, it can also exhaust itself even if it is bare-metal. To get around it, there are a couple of daemons that can be installed.
Query the amount of random entropy available on a system:
$ cat /proc/sys/kernel/random/entropy_avail
3120
