[ClusterLabs] Two nodes cluster issue

[Klaus Wenninger]

On 07/24/2017 05:37 PM, Kristián Feldsam wrote:
> I personally think that power off node by switched pdu is more safe,
> or not?

True if that is working in you environment. If you can't do a physical setup
where you aren't simultaneously loosing connection to both your node and
the switch-device (or you just want to cover cases where that happens)
you have to come up with something else.

>
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>> On 24 Jul 2017, at 17:27, Klaus Wenninger <kwenning at redhat.com
>> <mailto:kwenning at redhat.com>> wrote:
>>
>> On 07/24/2017 05:15 PM, Tomer Azran wrote:
>>> I still don't understand why the qdevice concept doesn't help on
>>> this situation. Since the master node is down, I would expect the
>>> quorum to declare it as dead.
>>> Why doesn't it happens?
>>
>> That is not how quorum works. It just limits the decision-making to
>> the quorate subset of the cluster.
>> Still the unknown nodes are not sure to be down.
>> That is why I suggested to have quorum-based watchdog-fencing with sbd.
>> That would assure that within a certain time all nodes of the
>> non-quorate part
>> of the cluster are down.
>>
>>>
>>>
>>>
>>> On Mon, Jul 24, 2017 at 4:15 PM +0300, "Dmitri
>>> Maziuk" <dmitri.maziuk at gmail.com
>>> <mailto:dmitri.maziuk at gmail.com>> wrote:
>>>
>>>     On 2017-07-24 07:51, Tomer Azran wrote:
>>>     > We don't have the ability to use it.
>>>     > Is that the only solution?
>>>
>>>     No, but I'd recommend thinking about it first. Are you sure you will 
>>>     care about your cluster working when your server room is on fire? 'Cause 
>>>     unless you have halon suppression, your server room is a complete 
>>>     write-off anyway. (Think water from sprinklers hitting rich chunky volts 
>>>     in the servers.)
>>>
>>>     Dima
>>>
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>>
>> -- 
>> Klaus Wenninger
>>
>> Senior Software Engineer, EMEA ENG Openstack Infrastructure
>>
>> Red Hat
>>
>> kwenning at redhat.com   
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