Update group_vars files in folio-ansible to remove Java memory settings

Closed this ticket as done. However, there is still for the group_vars of "release" and "next-release".

The -Xmx settings are now removed from snapshot and testing.

I have done some testing over the last few days.

With a branch of folio-ansible, did the Jenkins fresh build of folio-snapshot-test, then did ssh to the instance and gathered statistics about the memory usage by each docker container.

• A) Attachment summary-201910110824.txt – After one run of statistics gathering.

• B) Attachment summary-201910132248.txt – After doing some data loading of MARC records, some inventory search/display, a number of runs of statistics gathering thoughout the day.

Then removed the -Xmx settings in folio-ansible group_vars for "snapshot" and "snapshot-core" only. (The mod-agreements and mod-invoice have different options, so not touching those.)

Did the Jenkins fresh build of folio-snapshot-test, then activity and statistics gathering.

• C) Attachment summary-201910140109.txt – After four runs statistics gathering. After mod-agreements has finished loading.

• D) Attachment summary-201910140252.txt – After doing some data loading of MARC records, some inventory search/display, some Checkouts, a number of runs of statistics gathering thoughout the day.

Some notes about the statistics summaries:

The first part is just showing entries from the individual stats files for a couple of modules.

The second part shows a crude chart of the change in memory usage. Two characters for each stats run. So "__" means no change. The positive numbers show an increase on a scale of 1 to 5, where +5 is 10% (or more) increase, and +1 is 0.5 percent increase. Negative numbers are a reduction in memory usage.

It seems that the memory usage is as expected after removing the -Xmx settings.

– We will certainly need to test it, but as I understand it, the UseCGroupMemoryLimitForHeap option simply tells Java to see the container limit as the total available memory. Java then operates as usual on a physical system, regulating its heap size to remain within the total memory limit (presumably setting max heap to less than the total size). I did some cursory testing with mod-notes, and that did seem to be the case.

Question on this one, apologies if I'm reading this wrong. In this transition phase the container memory limit is set to 1.33 * the value of the max heap size in folio-ansible like this:

When the this is removed from folio ansible, the ld has:

Wouldn't we lose that 1/3 bit of headroom for the OS etc, and get OOM killed again if the main java process reaches the max heap size?