c17465be03
Automatic merge from submit-queue
Introduce node memory pressure condition to scheduler
Following the work done by @derekwaynecarr at https://github.com/kubernetes/kubernetes/pull/21274, introducing memory pressure predicate for scheduler.
Missing:
* write down unit-test
* test the implementation
At the moment this is a heads up for further discussion how the new node's memory pressure condition should be handled in the generic scheduler.
**Additional info**
* Based on [1], only best effort pods are subject to filtering.
* Based on [2], best effort pods are those pods "iff requests & limits are not specified for any resource across all containers".
[1] 542668cc79/docs/proposals/kubelet-eviction.md (scheduler)
[2] https://github.com/kubernetes/kubernetes/pull/14943