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-dns-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.
Tested with 4.5.0-0.nightly-2020-09-26-031740 and passed. # git show commit bd312639caff6e1578c4777ccc7d10fb5a6707fd (HEAD -> 4.5.0-0.nightly-2020-09-26-031740, origin/release-4.5) Merge: f9e4dfc9 87bae412 Author: OpenShift Merge Robot <openshift-merge-robot.github.com> Date: Fri Sep 25 21:44:49 2020 +0000 Merge pull request #198 from sgreene570/release-4.5-bz-1880311 [Release 4.5] Bug 1880311: 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/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/client-go v0.18.9
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