Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

Bug 1880315

Summary: [release 4.5] cluster-ingress-operator: Fix bug in reflector not recovering from "Too large resource version"
Product: OpenShift Container Platform Reporter: Lukasz Szaszkiewicz <lszaszki>
Component: NetworkingAssignee: Stephen Greene <sgreene>
Networking sub component: router QA Contact: Hongan Li <hongli>
Status: CLOSED ERRATA Docs Contact:
Severity: high    
Priority: high CC: aos-bugs, sgreene, sople
Version: 4.5   
Target Milestone: ---   
Target Release: 4.5.z   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Cause: k8s dependencies on the release-4.5 branch of the cluster-ingress-operator were out of date. Consequence: cluster-ingress-operator was shipping some upstream bugs in vendored dependency code Fix: Update clutser-ingress-operator dependencies to kubernetes v0.18.9 from 0.18.3 Result: cluster-ingress-operator is now not shipping a few known upstream bugs, mainly https://github.com/kubernetes/kubernetes/pull/92688
 Story Points: ---
Clone Of: Environment:
Last Closed: 2020-10-12 15:47:56 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:
Bug Depends On: 1880369    
Bug Blocks: 1879901    

Description Lukasz Szaszkiewicz 2020-09-18 09:45:27 UTC 
A recent fix in the reflector/informer https://github.com/kubernetes/kubernetes/pull/92688 prevents components/operators from entering a hotloop and stuck.

There are already reported cases that have run into that issue and were stuck for hours or even days. For example https://bugzilla.redhat.com/show_bug.cgi?id=1877346.

The root cause of the issue is the fact that a watch cache is initialized from the global revision (etcd) and might stay on it for an undefined period (if no changes were (add, modify) made). 
That means that the watch cache across server instances may be out of sync. 
That might lead to a situation in which a client gets a resource version from a server that has observed a newer rv, disconnect (due to a network error) from it, and reconnect to a server that is behind, resulting in “Too large resource version“ errors.

More details in https://github.com/kubernetes/kubernetes/issues/91073 and https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1904-efficient-watch-resumption


It looks like the issue only affects 1.18. According to https://github.com/kubernetes/kubernetes/issues/91073#issuecomment-652251669 the issue was first introduced in that version by changes done to the reflector. 
The fix is already present in 1.19.


Please make sure that cluster-ingress-operator is using a client-go that includes https://github.com/kubernetes/kubernetes/pull/92688 if not please use this BZ and file a PR.
In case you are using a framework to build your operator make sure it uses the right version of the client-go library.
Comment 3 Hongan Li 2020-09-27 05:54:36 UTC 
Tested with 4.5.0-0.nightly-2020-09-26-031740 and passed.

# git show
commit 171507d5814b6ba081cab72ffa2afd6c52d1f283 (HEAD -> 4.5.0-0.nightly-2020-09-26-031740, origin/release-4.5)
Merge: 9c9ee8e7 b7d913a2
Author: OpenShift Merge Robot <openshift-merge-robot.github.com>
Date:   Fri Sep 25 23:24:56 2020 +0000

    Merge pull request #461 from sgreene570/release-4.5-bz-1880315
    
    [Release 4.5] Bug 1880315: Fix bug in reflector not recovering from "Too large resource version"

# grep v0.18.9 go.mod 
	k8s.io/api v0.18.9
	k8s.io/apimachinery v0.18.9
	k8s.io/apiserver v0.18.9
	k8s.io/client-go v0.18.9
# grep v0.18.9 ./vendor/modules.txt 
# k8s.io/api v0.18.9
# k8s.io/apimachinery v0.18.9
# k8s.io/apiserver v0.18.9
# k8s.io/client-go v0.18.9
Comment 6 errata-xmlrpc 2020-10-12 15:47:56 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 (OpenShift Container Platform 4.5.14 bug fix 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/RHBA-2020:3843