Bug 764173 (GLUSTER-2441)

Summary:	Allow round-robin host lookups to retrieve client configuration
Product:	[Community] GlusterFS	Reporter:	Joe Julian <joe>
Component:	fuse	Assignee:	Kaushal <kaushal>
Status:	CLOSED CURRENTRELEASE	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	3.1.2	CC:	amarts, gluster-bugs
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Joe Julian 2011-02-17 16:17:21 UTC

When mounting a volume, the servername is specified to retrieve the volume configuration. If that server is down, the client cannot proceed.

If the client could handle round-robin dns responses, it could sequentially try the responses until it succeeds, allowing the client to start even with a down server.

For instance:
  host www.google.com
returns
  www.google.com is an alias for www.l.google.com.
  www.l.google.com has address 74.125.53.106
  www.l.google.com has address 74.125.53.147
  www.l.google.com has address 74.125.53.99
  www.l.google.com has address 74.125.53.103
  www.l.google.com has address 74.125.53.104
  www.l.google.com has address 74.125.53.105

If this host was used to mount the volume:
  mount -t glusterfs www.google.com:searchdata
the client would first query 74.125.53.106. If it did not succeed in retrieving the vol file for searchdata, it would then try 74.125.53.147, etc.

Comment 1 Amar Tumballi 2011-07-28 01:55:59 UTC

Check the current behavior, see what all needs to change for bringing in RR DNS for initial getspec.

Comment 2 Anand Avati 2011-09-19 03:45:38 UTC

CHANGE: http://review.gluster.com/239 (Enables usage of 'volfile-max-fetch-attempts' option of glusterfsd.) merged in master by Vijay Bellur (vijay)

Comment 3 Kaushal 2011-09-19 06:26:26 UTC

With the enabling of this option, gluster attempts to establish the connection the given number of times. If a server has multiple ips, each connection uses a different ip from the list provided by dns resolution.
So this in a way solves the problem.

Comment 4 Anand Avati 2011-09-19 08:36:44 UTC

CHANGE: http://review.gluster.com/455 (This is a followup patch to  e378778686fca24934e76c41e6496b12162a5420) merged in master by Vijay Bellur (vijay)