Ubuntu Server 16.04.1 LTS: OOM Killer gone wild?

Question

linux

Hello dear community!
After the next update on the servers, OOM Killer unpredictably killed samba and the virtual machine several times. The configuration did not change, and there were no changes in the loads either. During the year of operation, nothing like this was observed.
The first server performs the function of a file server. The Samba server crash incident has been reported once in the last two days. On board 8GB of RAM:
Log fragment
On the second server, the VirtualBox crash incident was registered four times in the last two days since the update: Log fragment
I
Log fragment II Log
fragment III
After that, the memory appetites of the virtual machine were reduced by half, but:
Fragment of log IV
Tell me where to dig, what to watch and how to calm down OOM Killer?
To be honest, even with the most severe shortages of RAM, I have never encountered it.

Answer 1

In general, the problem was solved by installing the kernel version 4.8.0-34.
Kernel version 4.4.0-59 (the latest from LTS) leads to the problem described above. Apparently, the lack of memory is somehow connected with the file cache, because it was he who occupied the main part of the memory.

Answer 2

Here is what the hoster answered me about this error, although the memory was 512 MB:

Set vm.overcommit_memory to 1 in sysctl.conf and apply the settings with sysctl -p, this will fix possible OOM issues when a process requests too much virtual memory.