[Gluster-users] split-brain recovery automation, any plans?

[Darrell Budic]

FYI, it’s my experience that “yum upgrade” will stop the running glistered (and possibly the running glusterfsds) during it’s installation of new gluster components. I’ve also noticed it starts them back up again during the process.

Ie, yesterday I upgraded a system to 3.7.13:

systemctl stop glusterd
<manually kill all glusterfsds>
yum upgrade

and discovered that glusterd was running again, and had started during the yum upgrade processing. All it’s glusterfsds had also started. Somewhat annoying, actually, because I had been planning to reboot the server to switch to the latest kernel as part of the process, but really didn’t feel like interrupting the heals at that time.

This probably didn’t have much impact on you, but it would have restarted any healing that was a result of the upgrade downtime twice. You may have caused yourself some extra wait for the first round of healing to conclude if stuff was using those volumes at the time. If you didn’t wait for those to conclude before starting your next upgrade, you could have caused a split brain on affected active files.

  -Darrell

> On Jul 12, 2016, at 10:57 AM, Dmitry Melekhov <dm at belkam.com> wrote:
> 
> 
> 
> 12.07.2016 17:38, Pranith Kumar Karampuri пишет:
>> Did you wait for heals to complete  before upgrading second node?
> 
> no...
> 
>> 
>> On Tue, Jul 12, 2016 at 3:08 PM, Dmitry Melekhov <dm at belkam.com <mailto:dm at belkam.com>> wrote:
>> 12.07.2016 13:31, Pranith Kumar Karampuri пишет:
>>> 
>>> 
>>> On Mon, Jul 11, 2016 at 2:26 PM, Dmitry Melekhov < <mailto:dm at belkam.com>dm at belkam.com <mailto:dm at belkam.com>> wrote:
>>> 11.07.2016 12:47, Gandalf Corvotempesta пишет:
>>> 2016-07-11 9:54 GMT+02:00 Dmitry Melekhov < <mailto:dm at belkam.com>dm at belkam.com <mailto:dm at belkam.com>>:
>>> We just got split-brain during update to 3.7.13 ;-)
>>> This is an interesting point.
>>> Could you please tell me which replica count did you set ?
>>> 
>>> 3
>>> 
>>> With replica "3" split brain should not occurs, right ?
>>> 
>>> I guess we did something wrong :-)
>>> 
>>> Or there is a bug we never found? Could you please share details about what you did?
>> 
>> upgraded to 3.7.13 from 3.7.11 using yum, while at least one VM is running :-)
>> on all 3 servers, one by one:
>> 
>> yum upgrade
>> systemctl stop glusterd 
>> than killed glusterfsd processes using kill 
>> and systemctl start glusterd
>> 
>> then next server....
>> 
>> after this we tried to restart VM, but it failed, because we forget to restart libvirtd, and it used old libraries,
>> I guess this is point where we got this problem.
>> 
>>>  
>>> 
>>> I'm planning a new cluster and I would like to be protected against
>>> split brains.
>>> 
>>> _______________________________________________
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>>> Gluster-users at gluster.org <mailto:Gluster-users at gluster.org>
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>>> 
>>> 
>>> -- 
>>> Pranith
>> 
>> 
>> 
>> 
>> -- 
>> Pranith
> 
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