Running Openshift 3.11 with project ResourceQuotas and LimitRanges enforced, I am trying to understand how I can utilise the entire of my project CPU quota based on the "actual current usage" rather than what I have "reserved".
As a simple example, if my question is not clear:
If I have a project with a ResourceQuota of 2 Core CPU
apiVersion: v1
kind: ResourceQuota
metadata:
name: compute-resources
spec:
hard:
limits.cpu: "2"I have a number of long running containers which are often idle, waiting for requests. So are not actually using much CPU. When requests start appearing I want the effected container to be able to "burst", allowing CPU usage up to the remaining CPU quota available in the project based on what is actually being used (I have no issue with the 100ms CFS resolution).
I need to enforce the maximum the project can have in total, hence the limits.cpu ResourceQuota. But, I must therefore also provide the limits.cpu for each container I create (explicitly or via LimitRange defaults) e.g:
...
spec:
containers:
...
resources:
limits:
cpu: "2"
requests:
cpu: 200mThis however will only work with the first container I create - the second container with the same settings will exceed the project quotas limits.cpu. But the container is just idle doing almost nothing after it's initial startup sequence.
Is it not possible in my scenario above to have it deallocate 200m from the quota for each container based on the request.cpu and burst up to 1800m? ( 1600m of 2000m quota unused + initial 200m requested )
I have read through the following, the overcommit link seemed promising, but I am still stuck.
Is what I am trying to do possible?