Add RAM to cloud_properties to set memory caps on Garden containers

[jrbudnack]

Hi folks -
My colleagues and I are running a few bosh-lite VM's in AWS to do some manifest validation before passing changes on to a "real" microbosh environment. Therefore, we have a few central bosh-lites running (one for each set of environments) that run multiple deployments. Currently, we're running into a problem where the Garden containers consume so much memory (running in a 32GB bosh-lite btw) that other Garden containers become unable to consume memory, and we have to restart the VM. In researching this problem, I was able to query Garden in bosh-lite (logged in as vcap) with the following command to get the memory limits - according to Garden, this limit is not being set - even if I specifically set it in the resource pools in any of the manifests:

The command:
for i in $(curl -s http://127.0.0.1:7777/containers | jq -r '.handles[]'); do echo $(curl -s "http://127.0.0.1:7777/containers/$i/limits/memory" | jq -r '.limit_in_bytes'); done;

The output:
9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000 9223372036854772000

It has been confirmed in the cf-bosh forum that this is expected behavior. Would it be possible to add manifest-driven memory caps in the future?

So for example:

cloud_properties:
ram: 2048

This could help us diagnose a memory-hogging release, without it crashing all of bosh-lite.

Let me know if you need further details - Thanks!
Jeremy