Thanks Gerry.
Hi Reid,
The shared storage solution we are using has clustering capabilities of its
own built into it and is able to remotely fence off the lost node, all we
need to do is run the command to expel/fence the lost node as part of our
own custom fencing agent on the surviving node.
FYI, the shared storage solution I am referring to here is IBM Spectrum
Scale.
Thanks,
Phil Stedman
Db2 High Availability Development and Support
Email: pmste...@us.ibm.com
From: Gerry R Sommerville/Markham/IBM
To: nw...@redhat.com
Cc: developers@clusterlabs.org, Toby Haynes/Toronto/IBM@IBMCA, Alan
Y Lee/Toronto/IBM@IBMCA, Philippe M Stedman/Silicon
Valley/IBM@IBMUS
Date: 07/30/2020 11:55 AM
Subject: Re: [EXTERNAL] Re: [ClusterLabs Developers] How to implement
fencing agent with no associated hardware device with
Pacemaker?
Seems like we lost Phil in the first reply.... Adding him back.
Gerry Sommerville
Db2 Development, pureScale Domain
E-mail: ge...@ca.ibm.com
----- Original message -----
From: Reid Wahl <nw...@redhat.com>
To: developers@clusterlabs.org
Cc: Toby Haynes <thay...@ca.ibm.com>, Gerry R Sommerville
<ge...@ca.ibm.com>, Alan Y Lee <yka...@ca.ibm.com>
Subject: [EXTERNAL] Re: [ClusterLabs Developers] How to implement fencing
agent with no associated hardware device with Pacemaker?
Date: Wed, Jul 29, 2020 11:42 PM
I didn't see the phrase "how to develop" until after I sent the previous
message. What is the reason for needing to develop a custom fencing agent?
An already-built one might save you some work.
Basically, you need some reliable method to cut off an unhealthy node's
access to shared storage, without depending on that node being responsive.
So for example, anything that involves logging into the failed node is
unreliable.
On Wed, Jul 29, 2020 at 8:40 PM Reid Wahl <nw...@redhat.com> wrote:
If you have a hardware **watchdog timer**, then sbd is a good option.
With shared storage, you can also implement fence_sbd.
KVM virtual machines also offer an emulated hardware watchdog. I'm not
sure whether that would fit your criteria or not -- it depends on whether
you're only excluding a management interface like an iLO/IMM, or whether
you're also excluding a watchdog timer.
If you can't use sbd or conventional power fencing (e.g., fence_ipmilan),
then you may be able to use fence_scsi or fence_mpath since you have
shared storage.
What hardware or virtualization platform are you running on, and is there
a particular reason you don't want to associate fencing with a hardware
device?
On Wed, Jul 29, 2020 at 8:34 PM Philippe M Stedman <pmste...@us.ibm.com>
wrote:
Hi ClusterLabs developers,
I am looking into how to develop a fencing agent for Pacemaker that is
not associated to any underlying hardware device. In our case we have
two servers (we will expand to more in the future) which have access to
shared storage. When one of the two nodes fails, we expect the
surviving node to invoke our user-defined fencing agent and run a
series of commands which will "expel" the lost host from accessing
shared storage.
Do you have any advice on how to go about implementing such a solution?
All the examples I can find online revolve around using some sort of
underlying hardware device to implement fencing.
Help is greatly appreciated.
Thanks,
Phil Stedman
Db2 High Availability Development and Support
Email: pmste...@us.ibm.com
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--
Regards,
Reid Wahl, RHCA
Software Maintenance Engineer, Red Hat
CEE - Platform Support Delivery - ClusterHA
--
Regards,
Reid Wahl, RHCA
Software Maintenance Engineer, Red Hat
CEE - Platform Support Delivery - ClusterHA
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