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https://issues.apache.org/jira/browse/CLOUDSTACK-10305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16376957#comment-16376957
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ASF subversion and git services commented on CLOUDSTACK-10305:
--------------------------------------------------------------
Commit 703054964a9bae27a563412c35166bae515d10e3 in cloudstack's branch
refs/heads/master from [~nicolas.vazquez]
[ https://gitbox.apache.org/repos/asf?p=cloudstack.git;h=7030549 ]
CLOUDSTACK-10305: Rare race condition in KVM migration (#2466)
There is a race condition in the monitoring of the migration process on KVM. If
the monitor wakes up in the tight window after the migration succeeds, but
before the migration thread terminates, the monitor will get a LibvirtException
“Domain not found: no domain with matching uuid” when checking on the migration
status. This in turn causes CloudStack to sync the VM state to stop, in which
it issues a defensive StopCommand to ensure it is correctly synced.
Fix: Prevent LibvirtException: "Domain not found" caused by the call to
dm.getInfo()
> Rare race condition in KVM migration
> ------------------------------------
>
> Key: CLOUDSTACK-10305
> URL: https://issues.apache.org/jira/browse/CLOUDSTACK-10305
> Project: CloudStack
> Issue Type: Bug
> Security Level: Public(Anyone can view this level - this is the
> default.)
> Reporter: Nicolas Vazquez
> Priority: Major
> Fix For: 4.11.1.0
>
>
> There is a race condition in the monitoring of the migration process on KVM.
> If the monitor wakes up in the tight window after the migration succeeds, but
> before the migration thread terminates, the monitor will get a
> LibvirtException “Domain not found: no domain with matching uuid” when
> checking on the migration status. This in turn causes CloudStack to sync the
> VM state to stop, in which it issues a defensive StopCommand to ensure it is
> correctly synced.
> This is issue is reported under these conditions:
> * VM migration has physically finished
> * Migration thread executor is still not marked as terminated
> From the migration monitoring process, as VM has been migrated, that domain
> cannot be found (we should get the destination domain from the migration
> thread later) and the LibvirtException is thrown: {{LibvirtException “Domain
> not found: no domain with matching uuid”}}.
> So basically the idea is just logging the issue but not suspending the VM as
> the migration has already been performed, but the migration thread is not
> marked as finished. Once the migrarion thread is marked as finished, the
> migration monitoring process (while loop) ends and the migration command
> wrapper would continue its execution.
> Regarding your last question, we won't need to suspend the VM in this case as
> the migration has already been performed. VM suspension will take place
> whenever the migration is in progress and those conditions are met
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