Bug 1292311

Summary:	[DOCS] Install guide notes that master and etcd cannot be together in HA config
Product:	OpenShift Container Platform	Reporter:	Veer Muchandi <veer>
Component:	Documentation	Assignee:	Alex Dellapenta <adellape>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Vikram Goyal <vigoyal>
Severity:	medium	Docs Contact:	Vikram Goyal <vigoyal>
Priority:	high
Version:	3.1.0	CC:	adellape, aos-bugs, jokerman, mmccomas
Target Milestone:	---
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Hardware:	All
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-05-31 18:24:09 UTC	Type:	Bug
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Veer Muchandi 2015-12-17 01:33:07 UTC

Document URL: 
https://access.redhat.com/documentation/en/openshift-enterprise/3.1/installation-and-configuration/chapter-2-installing#configuring-ansible

Section Number and Name: 
2.4.3.2

Describe the issue: 
Here is what the note says
NOTE
When specifying multiple etcd hosts, external etcd is installed and configured. Clustering of OpenShift’s embedded etcd is not supported.

Here is what Mike said
http://post-office.corp.redhat.com/archives/aos-devel/2015-November/msg00542.html


Suggestions for improvement: 

Fix the defect

Additional information:

Comment 1 Alex Dellapenta 2015-12-18 18:12:44 UTC

This was not meant to suggest that they could not be collocated, just that if you specify multiple etcd hosts, the standalone version of etcd is installed, instead of the etcd that is embedded in OpenShift itself. Calling it "external etcd" is probably the confusion here, but also we can add some language specifically about collocation to clear things up.

Comment 2 Veer Muchandi 2015-12-18 18:16:23 UTC

Yes clarifying on colocation will help. 
During my interaction with the customer, I said that colocation is possible and customer pointed this out and I got confused. Based on your answer I understand that colocation is actually possible. 

It also helps if we clarify whether the 3 masters (or odd number of masters) are required for the purpose of colocation with etcd. Can we manage with 2 masters for HA if etcd is not collocated? Or are there any other implications?

Comment 4 Scott Dodson 2018-05-16 16:52:03 UTC

The master services themselves have no quorum or requirement that they have an odd number of hosts. However, obviously for HA you need at least two and the overwhelming majority of installations colocate etcd and master services so it just makes sense to have three uniform hosts.

Comment 5 Alex Dellapenta 2018-05-22 18:46:23 UTC

Removed note referencing embedded etcd (since it is no longer supported in 3.7+):

[3.7]  https://github.com/openshift/openshift-docs/pull/9492
[master] https://github.com/openshift/openshift-docs/pull/9491

(It was already removed in 3.9 and 3.10 for some reason.)

Updated changes for 3.6:

https://github.com/openshift/openshift-docs/pull/9495

Based on review there, 3.5 PR incoming.

Comment 6 Alex Dellapenta 2018-05-22 19:25:30 UTC

3.5 and 3.6 changes reviewed and merged:

[3.5] https://github.com/openshift/openshift-docs/pull/9498
[3.6] https://github.com/openshift/openshift-docs/pull/9495

Comment 7 Alex Dellapenta 2018-05-31 18:24:09 UTC

https://docs.openshift.com/container-platform/3.5/architecture/infrastructure_components/kubernetes_infrastructure.html#high-availability-masters