[ClusterLabs] Antw: [EXT] Inquiry - remote node fencing issue

[Andrei Borzenkov]

On Thu, Oct 28, 2021 at 10:30 AM Ulrich Windl
<Ulrich.Windl at rz.uni-regensburg.de> wrote:
>
> Fencing _is_ a part of failover!
>

As any blanket answer this is mostly incorrect in this context.

There are two separate objects here - remote host itself and pacemaker
resource used to connect to and monitor state of remote host.

Remote host itself does not failover. Resources on this host do, but
OP does not ask about it.

Pacemaker resource used to monitor remote host may failover as any
other cluster resource. This failover does not require any fencing *of
remote host itself*, and in this particular case connection between
two cluster nodes was present all the time (at least, as long as we
can believe logs) so there was no reason for fencing as well. Whether
pacemaker should attempt to failover this resource to another node if
connection to remote host fails, is subject to discussion.

So fencing of the remote host itself is most certainly *not* part of
the failover of the resource that monitors this remote host.

> >>> "Janghyuk Boo" <Janghyuk.Boo at ibm.com> schrieb am 26.10.2021 um 22:09 in
> Nachricht
> <OF6751AF09.DD2C657C-ON0025877A.006EA8CB-0025877A.006EB632 at ibm.com>:
> Dear Community ,
> Thank you Ken for your reply last time.
> I attached the log messages as requested from the last thread.
> I have a Pacemaker cluster with two cluster nodes with two network interfaces
> each, and two remote nodes and a prototyped fencing agent(GPFS-Fence) to cut a
> hosts access from the clustered filesystem.
> I noticed that remote node gets fenced when the quorum node its connected to
> gets fenced or experiences network failure.
> For example, when I disconnected srv-2 from the rest of the cluster by using
> iptables on srv-2
> iptables -A INPUT -s [IP of srv-1] -j DROP ; iptables -A OUTPUT -s [IP of
> srv-1] -j DROP
> iptables -A INPUT -s [IP of srv-3] -j DROP ; iptables -A OUTPUT -s [IP of
> srv-3] -j DROP
> iptables -A INPUT -s [IP of srv-4] -j DROP ; iptables -A OUTPUT -s [IP of
> srv-4] -j DROP
> I expected that remote node jangcluster-srv-4 would failover to srv-1 given my
> location constraints,
> but remote node’s monitor ‘jangcluster-srv-4_monitor’ failed and srv-4 was
> getting fenced before attempting to failover.
> What would be the proper way to simulate the network failover?
> How can I configure the cluster so that remote node srv-4 fails over instead
> of getting fenced?
>
>
>
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