On Thu, Feb 5, 2026 at 12:56 PM Anton Gavriliuk <[email protected]> wrote:
> > Correct, in addition to two cluster nodes, there is dedicated 3rd node > physical server as qdevice. > > I'm thinking about two level fencing topology, 1st level - fence_ipmilan, > 2nd - diskless sbd (hpwdt, /dev/watchdog) > > But I can't add sbd as a 2nd level fencing, > > [root@memverge2 ~]# pcs stonith level add 2 memverge watchdog > Error: Stonith resource(s) 'watchdog' do not exist, use --force to override > Error: Errors have occurred, therefore pcs is unable to continue > [root@memverge2 ~]# > > So back to the original question - what is the most correct way of > implementing STONITH/fencing with fence_iomilan + diskless sbd (hpwdt, > /dev/watchdog) ? > Sorry then that I had overlooked qdevice (actually I thought I checked for it but ...). For adding the watchdog into a topology you have to make it visible before - just add it as any fencing-device with fence_watchdog as agent. There is a fence_watchdog script but that is just for the meta-data. Pacemaker will recognize that hand handle the actual fencing internally. Regards, Klaus > > Anton > > > -----Original Message----- > From: Andrei Borzenkov <[email protected]> > Sent: Thursday, February 5, 2026 1:17 PM > To: Cluster Labs - All topics related to open-source clustering welcomed < > [email protected]> > Cc: Anton Gavriliuk <[email protected]> > Subject: Re: [ClusterLabs] Question about two level STONITH/fencing > > On Thu, Feb 5, 2026 at 2:07 PM Klaus Wenninger <[email protected]> > wrote: > > > > > > > > On Wed, Feb 4, 2026 at 4:36 PM Anton Gavriliuk via Users < > [email protected]> wrote: > >> > >> > >> > >> Hello > >> > >> > >> > >> There is two-node (HPE DL345 Gen12 servers) shared-nothing DRBD-based > sync (Protocol C) replication, distributed active/standby pacemaker storage > metro-cluster. The distributed active/standby pacemaker storage > metro-cluster configured with qdevice, heuristics (parallel fping) and > fencing - fence_ipmilan and diskless sbd (hpwdt, /dev/watchdog). All > cluster resources are configured to always run together on the same node. > >> > >> > >> > >> The two storage cluster nodes and qdevice running on Rocky Linux 10.1 > >> > >> Pacemaker version 3.0.1 > >> > >> Corosync version 3.1.9 > >> > >> DRBD version 9.3.0 > >> > >> > >> > >> So, the question is – what is the most correct way of implementing > STONITH/fencing with fence_iomilan + diskless sbd (hpwdt, /dev/watchdog) ? > > > > > > The correct way of using diskless sbd with a two-node cluster is not > > to use it ;-) > > > > diskless sbd (watchdog-fencing) requires 'real' quorum and quorum > > provided by corosync in two-node mode would introduce split-brain > > which is the reason why sbd recognizes the two-node operation and > > replaces quorum from corosync by the information that the peer node is > currently in the cluster. This is fine for working with poison-pill fencing > - a single single shared disk then doesn't become a single-point-of-failure > as long as the peer is there. But for watchdog-fencing that doesn't help > because the peer going away would mean you have to commit suicide. > > > > and alternative with a two-node cluster is to step away from the actual > two-node design and go with qdevice for 'real' quorum. > > Hmm ... the original description does mention qdevice, although it is not > quite clear where it is located (is there the third node?) > > > You'll need some kind of 3rd node but it doesn't have to be a full > cluster node. > > > >
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