+++ This bug was initially created as a clone of Bug #1761920 +++

Description of problem:
openshift-tuned of the Node Tuning Operator issues unnecessary an expensive pod List() operation roughly every 60s.  The increased API usage becomes apparent (larger than any other system pod) at ~250 node count and fatal to an OpenShift cluster at ~1200 node count.

Version-Release number of selected component (if applicable):
Any 4.2 cluster.

How reproducible:
After scaling a cluster to ~250 nodes.

Steps to Reproduce:
1. Scale a cluster to ~250 node count and watch apiserver_request_count for the openshift-tuned pods.

Actual results:
openshift-tuned's apiserver_request_count higher than any other pod on the cluster.

Expected results:
Much lower apiserver_request_count for the openshift-tuned pod.

Additional info:
https://github.com/openshift/openshift-tuned/pull/30

--- Additional comment from  on 2019-11-05 09:49:34 UTC ---

Tested https://github.com/openshift/openshift-tuned/pull/30 on a 15-node (4.3.0-0.nightly-2019-11-02-092336) cluster with 2000 openshift-tuned pods.  The PR seemed to have helped significantly and no excessive number of API calls was registered.

Also tested the same setup with the *unpatched* openshift-tuned (without PR30).  Excessive number of API calls became apparent at around 250 openshift-tuned pods and the cluster "died" after having instantiated 1800 openshift-tuned pods.  This hopefully resolves the scalability issue to at least 2k nodes in the short term.

--- Additional comment from Mike Fiedler on 2019-11-07 13:25:14 UTC ---

Marking verified in build 4.3.0-0.nightly-2019-11-02-092336 based on Jiri's testing in comment 1.  Further analysis will be performed during 4.3 large scale testing on Azure.