Bug 1396742

Summary:	[ceph-ansible] : rolling_update.yml - description/comment about 'serial' config variable is incomplete/misleading
Product:	[Red Hat Storage] Red Hat Storage Console	Reporter:	Rachana Patel <racpatel>
Component:	ceph-ansible	Assignee:	Sébastien Han <shan>
Status:	CLOSED ERRATA	QA Contact:	Vidushi Mishra <vimishra>
Severity:	medium	Docs Contact:	Bara Ancincova <bancinco>
Priority:	unspecified
Version:	2	CC:	adeza, aschoen, ceph-eng-bugs, flucifre, gmeno, hnallurv, kdreyer, nthomas, racpatel, sankarshan, seb, shan, uboppana
Target Milestone:	---
Target Release:	2
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	ceph-ansible-2.1.9-1.el7scon	Doc Type:	Known Issue
Doc Text:	.The serial parameter must be set to 1 The `rolling_update.yml` Ansible playbook contains a comment about changing the value for the `serial` parameter to adjust the number of servers to be updated. However, upgrading many nodes in parallel can cause disruption to I/O operations. To avoid this problem, ensure that `serial` is set to `1`.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-06-19 13:16:11 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:	1383917

Description Rachana Patel 2016-11-19 15:15:14 UTC

Description of problem:
=======================
rolling_update.yml says

"# Change the value of 'serial:' to adjust the number of server to be updated."


AFAIK,
'serial' value indicates the number of nodes where the update happens together. So if we make 'serial' as 3  for MON, the update runs on 3 MONs at once and if we dont change it, it will update MON one after other.

Issue I have
1) 'serial' name itself is confusing, on setting that variable update happen in 'parallel' not in 'serial'

2) Description is misleading


"# Change the value of 'serial:' to adjust the number of server to be updated."


this might be interpreted as 'total no of server needs to be updated in cluster for that role'
e.g. how many MONs one wants update in cluster.

Adding completer description like, no of servers to be updated "togather" or "simultaneously" might make it less confusing

Additional info:

Comment 2 seb 2016-11-21 10:30:57 UTC

Rachana, what do you think of this? https://github.com/ceph/ceph-ansible/pull/1109

Comment 5 seb 2016-11-21 13:33:08 UTC

Thanks Harish, I added your suggestion.

Comment 6 Uday Boppana 2016-11-21 15:05:42 UTC

PM is OK with adding this as a release note in 2.1 as noted by Harish in comment 3

Comment 9 seb 2016-11-21 16:03:00 UTC

lgtm Bara thanks

Comment 11 seb 2016-11-30 15:06:22 UTC

still lgtm :)

Comment 12 Ken Dreyer (Red Hat) 2017-03-03 17:23:31 UTC

We think this is fixed in the latest builds currently undergoing testing
(ceph-ansible-2.1.9-1.el7scon as of this writing.) Rachana would you please retest with the latest builds?

Comment 17 errata-xmlrpc 2017-06-19 13:16:11 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, 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-2017:1496