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<DIV><FONT color=#000000 size=3 face=宋体>Hi all,</FONT></DIV>
<DIV><FONT color=#000000 size=3></FONT> </DIV>
<DIV><FONT color=#000000 size=3>I have a question about fixing a race condition
issue between deleting and soft reboot,</FONT></DIV>
<DIV><FONT color=#000000 size=3>the issue is that:</FONT></DIV>
<DIV><FONT color=#000000 size=3>1. If we soft reboot an instance, and then
delete it, the instance may not be deleted and stand on deleting task state,
this is because the bug below,</FONT></DIV>
<DIV><A
href="https://bugs.launchpad.net/nova/+bug/1111213">https://bugs.launchpad.net/nova/+bug/1111213</A></DIV>
<DIV>and I have fixed this bug yet several months ago(just for libvirt
driver).</DIV>
<DIV>2. The other issue is, if the instance is rebooted just before deleting the
files under instance dir, then it may become to a running deleted one, and
this bug is at below:</DIV>
<DIV><A
href="https://bugs.launchpad.net/nova/+bug/1246181">https://bugs.launchpad.net/nova/+bug/1246181</A></DIV>
<DIV>I want to fix it now, and I need your advice.</DIV>
<DIV>The commit is here: <A
href="https://review.openstack.org/#/c/54477/">https://review.openstack.org/#/c/54477/</A> ,
you can post your advice on gerrit or mail to me.</DIV>
<DIV> </DIV>
<DIV>The ways to fix bug #2 may be these(just for libvirt driver in my
mind):</DIV>
<DIV>1. Add a lock to reboot operation like the deleting operation, so the
reboot operation and the delete operation will be done in sequence. </DIV>
<DIV>But on the other hand, the soft reboot operation may cost 120s if the
instance doesn't support graceful shutdown, I think it is too long for a user to
delete an instance, so this may not be the best way.</DIV>
<DIV>2. Check the instance state at the last of _cleanup method in libvirt
driver, and if it is still running, destroy it again.</DIV>
<DIV>This way is usable but both Nikola Dipanov and I don't like this 'ugly'
way.</DIV>
<DIV>3. Check the instance vm state and task state in nova db before booting in
reboot, if it is deleted/deleting, stop the reboot process, this will access db
at driver level, it is a 'ugly' way, too.</DIV>
<DIV> </DIV>
<DIV>Nikola suggests that 'maybe we can leverage task/vm states and refactor how
reboot is done so we can back out of a reboot on a delete', but I think we
should let user delete an instance at any time and any state, so the delete
operation during 'soft reboot' may not be forbidden.</DIV>
<DIV> </DIV>
<DIV>Thanks and waiting for your voice!</DIV>
<DIV> </DIV>
<DIV align=left><FONT color=#c0c0c0 size=2
face=Verdana>2013-11-04</FONT></DIV><FONT size=2 face=Verdana>
<HR id=SignNameHR style="HEIGHT: 2px; WIDTH: 122px" align=left SIZE=2>
</FONT>
<DIV><FONT color=#c0c0c0 size=2 face=Verdana><SPAN
id=_FlashSignName>Wangpan</SPAN></FONT></DIV></STATIONERY></BODY></HTML>