[ClusterLabs] Antw: [EXT] Stonith failing

[Andrei Borzenkov]

17.08.2020 23:39, Jehan-Guillaume de Rorthais пишет:
> On Mon, 17 Aug 2020 10:19:45 -0500
> Ken Gaillot <kgaillot at redhat.com> wrote:
> 
>> On Fri, 2020-08-14 at 15:09 +0200, Gabriele Bulfon wrote:
>>> Thanks to all your suggestions, I now have the systems with stonith
>>> configured on ipmi.  
>>
>> A word of caution: if the IPMI is on-board -- i.e. it shares the same
>> power supply as the computer -- power becomes a single point of
>> failure. If the node loses power, the other node can't fence because
>> the IPMI is also down, and the cluster can't recover.
>>
>> Some on-board IPMI controllers can share an Ethernet port with the main
>> computer, which would be a similar situation.
>>
>> It's best to have a backup fencing method when using IPMI as the
>> primary fencing method. An example would be an intelligent power switch
>> or sbd.
> 
> How SBD would be useful in this scenario? Poison pill will not be swallowed by
> the dead node... Is it just to wait for the watchdog timeout?
> 

Node is expected to commit suicide if SBD lost access to shared block
device. So either node swallowed poison pill and died or node died
because it realized it was impossible to see poison pill or node was
dead already. After watchdog timeout (twice watchdog timeout for safety)
we assume node is dead.