[ClusterLabs] Antw: Re: Antw: [EXT] Stonith failing

[Andrei Borzenkov]

18.08.2020 10:10, Ulrich Windl пишет:
>>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 17.08.2020 um 17:19 in
> Nachricht
> <73d6ecf113098a3154a2e7db2e2a59557272024a.camel at redhat.com>:
>> 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.
> 
> This may not always be true: We had servers with three(!) power supplies and a
> BMC (what today is called "light-out management"). You could "power down" the
> server, while the BMC was still operational (and thus could "power up" the
> server again).
> With standard PC architecture these days things seem to be a bit more
> compicated (meaning "primitive")...
> 

BMC is powered by standby voltage. If AC input to all of your power
supplies is cut off, there is no standby voltage anymore. Just try to
unplug all power cables and see if BMC is still accessible.