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Bug 622446 - [vdsm] [libvirt] vm 'split brain' when 'vdsm' loose connection to 'libvirtd' after migration
Summary: [vdsm] [libvirt] vm 'split brain' when 'vdsm' loose connection to 'libvirtd' ...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: vdsm
Version: 6.1
Hardware: All
OS: Linux
low
high
Target Milestone: rc
: ---
Assignee: Eduardo Warszawski
QA Contact: Haim
URL:
Whiteboard:
: 601741 695391 (view as bug list)
Depends On:
Blocks: 581275 709788
TreeView+ depends on / blocked
 
Reported: 2010-08-09 11:55 UTC by Haim
Modified: 2014-01-13 00:46 UTC (History)
12 users (show)

Fixed In Version: vdsm-4.9-69.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
: 709788 (view as bug list)
Environment:
Last Closed: 2011-12-06 06:58:37 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
vdsm logs (1.36 MB, application/x-gzip)
2010-08-09 11:55 UTC, Haim 		no flags Details
Logs (2.63 MB, application/x-gzip)
2011-05-31 15:12 UTC, Jakub Libosvar 		no flags Details
vdsm - new 73 based (389.58 KB, application/x-gzip)
2011-06-07 10:07 UTC, Haim 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHEA-2011:1782 0 normal SHIPPED_LIVE new packages: vdsm 2011-12-06 11:55:51 UTC

Description Haim 2010-08-09 11:55:27 UTC 
Created attachment 437572 [details]
vdsm logs

Description of problem:

vm 'split brain' scenario is created in case vdsm loses its connection to libvirt somehow (*) on destination machine, and migration from source (valid source) to that destination takes place. 

migration is reported as 'failed', and 'qemu' process is so called dies, however, migration succeeds to destination on virsh, this results a state, where vdsm 'thinks' vm is down (and rhevm respectively), and will try to run this vm on different host, which will result 'split brain'.

(*) how ? 

1) make sure you have 2 hosts ('host-a' and 'host-b')
2) make sure you have connected storage (i use iscsi)
3) run the following commands on 'host-b' 
   - kill -STOP `pgrep libvirt`
   - service libvirtd restart 
4) create a new domain (machine) on 'host-a' and make sure it runs 
5) migrate this vm from 'host-a' to 'host-b' 

result: 

migration will fail on source, however, it will succeeds on libvirt.
Comment 1 Haim 2010-08-09 11:55:59 UTC 
libvirt-0.8.1-20.el6.x86_64
vdsm-4.9-12.el6.x86_64
qemu-kvm-0.12.1.2-2.106.el6.x86_64
Comment 3 Barak 2010-11-28 16:41:06 UTC 
This happens because we may miss the libvirt event (domain finished migration) when we were down. This should be solved by checking on recovery if we are migration destination then recheck VM status and if it's running change our VM status accordingly..
Comment 5 Dan Kenigsberg 2011-01-02 10:32:58 UTC 
*** Bug 601741 has been marked as a duplicate of this bug. ***
Comment 6 Eduardo Warszawski 2011-05-23 06:28:52 UTC 
*** Bug 695391 has been marked as a duplicate of this bug. ***
Comment 8 Jakub Libosvar 2011-05-31 15:11:50 UTC 
Using steps described in Description with vdsm-4.9-70.el6.x86_64, during migration the machine status in RHEV-M was down. After but according backend log, migration was in progress: 
2011-05-31 16:58:22,131 INFO  [com.redhat.rhevm.vdsbroker.VdsUpdateRunTimeInfo] (QuartzScheduler_Worker-12) vds::refreshVmList vm id 4f65e6ab-3bd1-4a69-be84-326ee9d988a8 is migrating to vds srh-11 ignoring it in the refresh till migration is done

Migration failed in RHEV-M at 17:02 according events. No ERROR in backend nor vdsm logs. Backend, source vds's and targer vds's vdsm and libvirt logs are attached in next comment.

In libvirt is error
16:57:46.712: 12070: error : remoteIO:10569 : Domain not found: no domain with matching uuid '4f65e6ab-3bd1-4a69-be84-326ee9d988a8'
Comment 9 Jakub Libosvar 2011-05-31 15:12:40 UTC 
Created attachment 502022 [details]
Logs
Comment 12 Haim 2011-06-07 10:07:09 UTC 
Created attachment 503440 [details]
vdsm - new 73 based
Comment 13 Haim 2011-06-12 09:24:32 UTC 
no repro on 74. fixed
Comment 14 errata-xmlrpc 2011-12-06 06:58:37 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.

http://rhn.redhat.com/errata/RHEA-2011-1782.html
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