[ClusterLabs] Fencing on 2-node cluster

[Digimer]

Fencing is required on all clusters, and specially on 2-node ones.

https://www.alteeve.com/w/The_2-Node_Myth

digimer

On 2018-06-20 05:53 PM, Casey & Gina wrote:
> Does this mean that fencing can't actually work in a 2-node cluster??  Or is it just that the delay needs set differently on one of the hosts and it will start working?
> 
>> On 2018-06-20, at 3:50 PM, Digimer <lists at alteeve.ca> wrote:
>>
>> On 2018-06-20 05:46 PM, Jehan-Guillaume de Rorthais wrote:
>>> On Wed, 20 Jun 2018 17:24:41 -0400
>>> Digimer <lists at alteeve.ca> wrote:
>>>
>>>> Make sure quorum is disabled. Quorum doesn't work on 2-node clusters.
>>>
>>> It does with the "two_node" parameter enabled in corosync.conf...as far as I
>>> understand it anyway...
>>
>> It doesn't, that option disables quorum in corosync.
>>
>> Quorum is floor(($nodes / 2) + 1). So in a 3-node, that is 3 -> 1.5 ->
>> 2.5 -> 2 votes needed for quorum. In a 2-node, that is 2 -> 1 -> 2 -> 2
>> votes needed for quorum, meaning you can't lose a node to operate (which
>> is kinda not HA :) ).
>>
>> -- 
>> Digimer
>> Papers and Projects: https://alteeve.com/w/
>> "I am, somehow, less interested in the weight and convolutions of
>> Einstein’s brain than in the near certainty that people of equal talent
>> have lived and died in cotton fields and sweatshops." - Stephen Jay Gould
> 
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-- 
Digimer
Papers and Projects: https://alteeve.com/w/
"I am, somehow, less interested in the weight and convolutions of
Einstein’s brain than in the near certainty that people of equal talent
have lived and died in cotton fields and sweatshops." - Stephen Jay Gould