Bug 2006714

Summary: add retry for etcd errors in kube-apiserver
Product: OpenShift Container Platform Reporter: Lukasz Szaszkiewicz <lszaszki>
Component: kube-apiserverAssignee: Lukasz Szaszkiewicz <lszaszki>
Status: CLOSED ERRATA QA Contact: Ke Wang <kewang>
Severity: high Docs Contact:
Priority: high    
Version: 4.10CC: aos-bugs, mfojtik, xxia
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Target Release: 4.10.0   
Hardware: Unspecified   
OS: Unspecified   
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: 2006717 (view as bug list) Environment:
Last Closed: 2022-03-10 16:12:32 UTC Type: Bug
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Bug Blocks: 2006717    

Description Lukasz Szaszkiewicz 2021-09-22 09:38:54 UTC 
The etcd client used by the API server should retry certain types of errors. The full list of retriable (codes.Unavailable) errors can be found at https://github.com/etcd-io/etcd/blob/main/api/v3rpc/rpctypes/error.go#L72.
This is already implemented by the etcd client just wasn't "enabled" in the API server


The fix seems to be real compare [1] to how it was just a few days ago [2]

[1] https://search.ci.openshift.org/?search=etcdserver%3A+leader+changed&maxAge=24h&context=1&type=junit&name=periodic.*4.10.*upgrade&excludeName=4.9%7C4.8%7Csingle-node&maxMatches=5&maxBytes=20971520&groupBy=job
[2] https://search.ci.openshift.org/?search=etcdserver%3A+leader+changed&maxAge=48h&context=1&type=junit&name=periodic.*4.10.*upgrade&excludeName=4.9%7C4.8%7Csingle-node&maxMatches=5&maxBytes=20971520&groupBy=job
Comment 2 Ke Wang 2021-09-26 11:48:45 UTC 
Compared the results between 4.9 and 4.10 with PR fix.

$ oc get clusterversion
NAME      VERSION                             AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.9.0-0.nightly-2021-09-25-094414   True        False         79m     Cluster version is 4.9.0-0.nightly-2021-09-25-094414

$ masters=$(oc get no -l node-role.kubernetes.io/master | sed '1d' | awk '{print $1}')
$ for node in $masters; do echo $node;oc debug no/$node -- chroot /host bash -c "grep -ir 'etcdserver: leader changed' /var/log/ | grep -v debug";done | grep kube-apiserver | wc -l
...
12


$ oc get clusterversion
NAME      VERSION                              AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.10.0-0.nightly-2021-09-23-210724   True        False         12m     Cluster version is 4.10.0-0.nightly-2021-09-23-210724

$ masters=$(oc get no -l node-role.kubernetes.io/master | sed '1d' | awk '{print $1}')
$ for node in $masters; do echo $node;oc debug no/$node -- chroot /host bash -c "grep -ir 'etcdserver: leader changed' /var/log/ | grep -v debug";done | grep kube-apiserver | wc -l
...
/var/log/kube-apiserver/termination.log:{"level":"warn","ts":"2021-09-26T11:11:24.026Z","logger":"etcd-client","caller":"v3/retry_interceptor.go:62","msg":"retrying of unary invoker failed","target":"etcd-endpoints://0xc00315e380/#initially=[https://10.0.0.2:2379;https://10.0.0.4:2379;https://10.0.0.5:2379;https://localhost:2379]","attempt":0,"error":"rpc error: code = Unavailable desc = etcdserver: leader changed"}
/var/log/kube-apiserver/termination.log:{"level":"warn","ts":"2021-09-26T11:11:24.026Z","logger":"etcd-client","caller":"v3/retry_interceptor.go:62","msg":"retrying of unary invoker failed","target":"etcd-endpoints://0xc0008f3500/#initially=[https://10.0.0.2:2379;https://10.0.0.4:2379;https://10.0.0.5:2379;https://localhost:2379]","attempt":0,"error":"rpc error: code = Unavailable desc = etcdserver: leader changed"}

Above warning logs from etcd-client, not from by the API server, so on 4.10, won't see certain errors of etcd, move the bug VERIFIED.
Comment 5 errata-xmlrpc 2022-03-10 16:12:32 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 4.10.3 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-2022:0056