Bug 1929944

Summary:	The etcdInsufficientMembers alert fires incorrectly when any instance is down and not when quorum is lost
Product:	OpenShift Container Platform	Reporter:	Clayton Coleman <ccoleman>
Component:	Etcd	Assignee:	Clayton Coleman <ccoleman>
Status:	CLOSED ERRATA	QA Contact:	ge liu <geliu>
Severity:	urgent	Docs Contact:
Priority:	urgent
Version:	4.7	CC:	mgugino, travi, wking
Target Milestone:	---
Target Release:	4.8.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Cause: Alert configuration based on upstream etcd is not suitable for Openshift configuration. Consequence: etcdInsufficientMembers alert fires incorrectly Fix: Change the expression to include pod label as well as instance label in the query. Result: alert fires only when the quorum is lost.	Story Points:	---
Clone Of:
Clones:	1930224 (view as bug list)		Environment:
Last Closed:	2021-07-27 22:45:14 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:
Bug Blocks:	1930224, 1930226, 1930876

Description Clayton Coleman 2021-02-18 01:58:30 UTC

etcdInsufficientMembers is supposed to fire when quorum is potentially lost. However, the difference in how upstream expects to configure etcd (instance label unique) and how OpenShift configures etcd (running in pods, so instance and pod label are unique) results in the alert firing spuriously during upgrades. This means the alert fires too eagerly.

The alert, once corrected, should only fire if we have reason to believe quorum is lost i.e. a majority of instances are down (must have (N+1)/2 instances up) where n is inferred from the expected number of scrape targets. The alert should have a better description and suggest possible areas to investigate, namely down control plane nodes or broken networking.

A runbook addition will come later.

Comment 2 Clayton Coleman 2021-02-18 14:18:31 UTC

Will be backported to 4.7 and 4.6

Comment 3 Michael Gugino 2021-02-18 15:33:20 UTC

Need to make sure we account for this bug: https://bugzilla.redhat.com/show_bug.cgi?id=1880759

Also, I suggest renaming this alert to EtcdQuorumLost to more clearly demonstrate the impact.  InsufficientMembers doesn't have much context.

Comment 9 errata-xmlrpc 2021-07-27 22:45:14 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