[ClusterLabs] Recommendation Fencing

[Ken Gaillot]

Hi,

It sounds like watchdog-only sbd is your best option.

The problem with fence_vmware in this situation is that if the
connection between the two sites is severed, the other site won't be
able to reach the vmware host to request fencing.

An alternative is to use a fencing topology, which allows you to
combine multiple fencing devices. You would have fence_vmware as the
first level and watchdog-only sbd as the second level. When fencing is
needed, the cluster would try fence_vmware first, and if that failed,
rely on sbd.

On Sat, 2024-08-31 at 15:12 +0000, Angelo M Ruggiero via Users wrote:
> Hi,
> 
> Thanks for the previous replies. I am currently reading them.
> 
> Can i be cheeky i have been researching and having some other
> "organisation issues" around fencing. 
> 
> Maybe it is possible to recommend what fencing and whether to use sbd
> with just watchdog or also with storage.  Or some pointers...
> 
> Here is my setup
> 
> 2 Node,  with a Quorum Device
> 
> nodes run on vmware and RHEL 8+ there is vmware watch available (i
> even tried it out a bit)
> 
> Each node is a different site, but they are close i.e approx 15 km
> with a good connection (i work for a big bank in switzerland)
> 
> Application DB Shared storage is given via nfs mounting and available
> on both side. The shared storage can be used at both sites. 
> 
> We want to run SAP with HANA the above setup and using pacemaker
> there are some restrictions around sbd and vmware but lets put that
> to one side just from a view of pacemaker what option i choose i have
> to make sure it is SAP Certified... Oh joy. 🙂
> 
> I see the following main options
> 
> Option 1. Just fence_vmware with no sbd at all
> 
> Option 2. Fence_vmware with sbd but just watchdog
> 
> Option 3. Fence_vmware with sbd, watchdog and share storage 
> 
> The organisational issue is that the sbd shared storage is considered
> non standard, although we are setting up Oracle RAC which needs
> similar setup.
> 
> What i read around at sort of think is good is option 3 as it provide
> posion pill, self fencing
> 
> What i do not have clear in my head and what i will work on next week
> to work out the pros and cons and what situations can be handled.
> 
> I have discounted other fence agents as I am not sure they work on
> vmware, but happy to be  told other options.
> 
> Any input gratefully received.
> 
> regards
> Angelo
> 
-- 
Ken Gaillot <kgaillot at redhat.com>