<div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:10pt" ><div dir="ltr" >Seems like we lost Phil in the first reply.... Adding him back.<br> </div>
<div dir="ltr" ><div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:10.5pt" ><div dir="ltr" ><div style="font-size: 12pt; font-weight: bold; font-family: sans-serif; color: #7C7C5F;" >Gerry Sommerville</div>
<div style="font-size: 10pt; font-weight: bold; font-family: sans-serif;" >Db2 Development, pureScale Domain</div>
<div style="font-size: 8pt; font-family: sans-serif; margin-top: 10px;" ><div><span style="font-weight: bold; color: #336699;" >E-mail: </span><a href="mailto:gerry@ca.ibm.com" style="color: #555">gerry@ca.ibm.com</a></div></div></div></div></div>
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<blockquote data-history-content-modified="1" dir="ltr" style="border-left:solid #aaaaaa 2px; margin-left:5px; padding-left:5px; direction:ltr; margin-right:0px" >----- Original message -----<br>From: Reid Wahl <nwahl@redhat.com><br>To: developers@clusterlabs.org<br>Cc: Toby Haynes <thaynes@ca.ibm.com>, Gerry R Sommerville <gerry@ca.ibm.com>, Alan Y Lee <ykalee@ca.ibm.com><br>Subject: [EXTERNAL] Re: [ClusterLabs Developers] How to implement fencing agent with no associated hardware device with Pacemaker?<br>Date: Wed, Jul 29, 2020 11:42 PM<br>
<div dir="ltr" ><div>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.</div>
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<div>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.</div></div>
<div><div dir="ltr" >On Wed, Jul 29, 2020 at 8:40 PM Reid Wahl <<a href="mailto:nwahl@redhat.com" target="_blank">nwahl@redhat.com</a>> wrote:</div>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" ><div dir="ltr" ><div>If you have a hardware **watchdog timer**, then sbd is a good option. With shared storage, you can also implement fence_sbd.</div>
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<div>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.</div>
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<div>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.</div>
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<div>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?</div></div>
<div><div dir="ltr" >On Wed, Jul 29, 2020 at 8:34 PM Philippe M Stedman <<a href="mailto:pmstedma@us.ibm.com" target="_blank">pmstedma@us.ibm.com</a>> wrote:</div>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" ><div><p><font size="2" >Hi ClusterLabs developers,</font><br><br><font size="2" >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.</font><br><br><font size="2" >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.<br><br>Help is greatly appreciated.<br><br>Thanks,</font><br><br><b><font size="2" >Phil Stedman</font></b><br><font size="2" >Db2 High Availability Development and Support<br>Email: <a href="mailto:pmstedma@us.ibm.com" target="_blank">pmstedma@us.ibm.com</a></font></p></div>_______________________________________________<br>Manage your subscription:<br><a href="https://lists.clusterlabs.org/mailman/listinfo/developers" rel="noreferrer" target="_blank">https://lists.clusterlabs.org/mailman/listinfo/developers</a><br><br>ClusterLabs home: <a href="https://www.clusterlabs.org/" rel="noreferrer" target="_blank">https://www.clusterlabs.org/</a></blockquote></div><br clear="all" ><br>--
<div dir="ltr" ><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div>Regards,<br> </div>Reid Wahl, RHCA</div>
<div>Software Maintenance Engineer, Red Hat</div>CEE - Platform Support Delivery - ClusterHA</div></div></div></div></div></div></div></div></div></div></div></div></div></div></blockquote></div><br clear="all" ><br>--
<div dir="ltr" ><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div dir="ltr" ><div><div>Regards,<br> </div>Reid Wahl, RHCA</div>
<div>Software Maintenance Engineer, Red Hat</div>CEE - Platform Support Delivery - ClusterHA</div></div></div></div></div></div></div></div></div></div></div></div></div></div></blockquote>
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