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Bug 1950026

Summary:	[Descheduler] Need better way to handle evicted pod count for removeDuplicate pod strategy
Product:	OpenShift Container Platform	Reporter:	RamaKasturi <knarra>
Component:	kube-scheduler	Assignee:	Jan Chaloupka <jchaloup>
Status:	CLOSED ERRATA	QA Contact:	RamaKasturi <knarra>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.8	CC:	aos-bugs, maszulik, mfojtik
Target Milestone:	---
Target Release:	4.8.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	No Doc Update
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-07-27 23:01:13 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description RamaKasturi 2021-04-15 15:28:18 UTC

Description of problem:
when removeDuplicates strategy is enabled, descheduler evicts the pod which are duplicates and then the pod gets recreated and descheduler thinks still there is a replica and it evicts the pod  again and this continues in a loop. Due to this when viewing metrics of evicted pods with RemoveDuplicate strategy the no.of pods which are evicted keeps growing continuously even though the cluster does not have so many pods which is confusing.

Version-Release number of selected components (if applicable):
Clusterkubedescheduleroperator.4.8.0-202104142158.p0

How reproducible:
Always

Steps to reproduce:
Install 4.8 descheduler
Enable TopologyAndDuplicates profile
Create pods using the command oc create dc hello --image=<image_name>
Edit the dc and change the replicas to 12
Change the descheduling interval to 60 seconds
Wait for one descheduler run to happen, browse through the prometheus UI and select descheduler_pods_evicted

Actual Results:
 You would see the graph of descheduler_pods_evicted keeps on increasing forever for removeDuplicates strategy

Expected Results:
   Need to determine the right way to show the evicted pod count for removeDuplicates strategy

Comment 1 Jan Chaloupka 2021-04-30 12:04:14 UTC

Will not be fixed in 4.8 timeframe

Comment 2 Jan Chaloupka 2021-05-20 14:09:25 UTC

Upstream PR under review

Comment 4 RamaKasturi 2021-06-11 13:11:36 UTC

currently blocked by the bug[1] for verification, once the bug moves to ON_QA i will verify this bug as well.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1970828

Comment 5 RamaKasturi 2021-06-15 11:23:26 UTC

Moving the bug to verified state as i see that removeDuplicate strategy works fine along with metrics shown in prometheus UI.

[knarra@knarra ~]$ oc get clusterversion
NAME      VERSION                             AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.8.0-0.nightly-2021-06-14-145150   True        False         132m    Cluster version is 4.8.0-0.nightly-2021-06-14-145150

steps followed to verify the same:
=================================
1) Install 4.8 cluster
2) Enable TopologyAndDuplicates profile
3) Create pods using the command oc create dc hello --image=<image_name>
4) Edit the dc and change the replicas to 12
5) Change the descheduling interval to 60 seconds
6) Wait for one descheduler run to happen, browse through the prometheus UI and select descheduler_pods_evicted

From the metrics you could see the right no.of pods that were evicted.

Tested the same with deployment & replicaset and it all worked fine.

Comment 8 errata-xmlrpc 2021-07-27 23:01:13 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: OpenShift Container Platform 4.8.2 bug fix and security update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2021:2438