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Sent: Tue Dec 14 2010 11:37:06 GMT-0700 (Mountain Standard Time)<br>
From: Dejan Muhamedagic <a class="moz-txt-link-rfc2396E" href="mailto:dejanmm@fastmail.fm"><dejanmm@fastmail.fm></a><br>
To: The Pacemaker cluster resource manager
<a class="moz-txt-link-rfc2396E" href="mailto:pacemaker@oss.clusterlabs.org"><pacemaker@oss.clusterlabs.org></a> <br>
Subject: Re: [Pacemaker] continue starting chain with failed group
resources
<blockquote cite="mid:20101214183705.GE30350@rondo.homenet" type="cite">
<pre wrap="">Hi,
On Mon, Dec 13, 2010 at 10:43:36PM -0700, Patrick H. wrote:
</pre>
<blockquote type="cite">
<pre wrap="">After tinkering with this for a few hours I finally have something working.
colocation co-raid inf: ( md_raid iscsi_1 iscsi_2 iscsi_3 )
</pre>
</blockquote>
<pre wrap=""><!---->
This should be noop. You'd want something like this, I think:
colocation co-raid inf: md_raid ( iscsi_1 iscsi_2 iscsi_3 )
</pre>
</blockquote>
No, that makes the md_raid service depend on all the iscsi services
being started, which I dont want<br>
<br>
<blockquote cite="mid:20101214183705.GE30350@rondo.homenet" type="cite">
<pre wrap=""></pre>
<blockquote type="cite">
<pre wrap="">order or-raid 0: ( iscsi_1 iscsi_2 iscsi_3 ) md_raid
Got rid of the group, changed the score on the order to 0, and
changed the grouping of both the colocation and order. This
*appears* to function as intended, but if anyone can point out any
pitfalls I'd appreciate it
-Patrick
Sent: Mon Dec 13 2010 21:12:04 GMT-0700 (Mountain Standard Time)
From: Patrick H. <a class="moz-txt-link-rfc2396E" href="mailto:pacemaker@feystorm.net"><pacemaker@feystorm.net></a>
To: The Pacemaker cluster resource manager <a class="moz-txt-link-rfc2396E" href="mailto:pacemaker@oss.clusterlabs.org"><pacemaker@oss.clusterlabs.org></a>
Subject: [Pacemaker] continue starting chain with failed group resources
</pre>
<blockquote type="cite">
<pre wrap="">Is there a way to continue down a chain of starting resources once
a previous resource hast tried to start, no matter if the try was
successful or not?
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
No, that's currently not possible to express. I think that you
should take the iSCSI resources out of the cluster and let them
start on boot _before_ the cluster manager. If there are not
enough disks, then the md_raid resource is going to fail.
</pre>
</blockquote>
Cant do that either. When the node that is currently using the iscsi
services fails, they have to be migrated over to another host so it can
assemble them into a raid array. If theyre not being managed by
pacemaker, they wont migrate.<br>
<br>
<br>
<br>
I made a few more tweaks from the configuration I posted earlier and it
seems to work pretty good with only one exception.<br>
colocation co-raid inf: ( md_raid iscsi_1 iscsi_2 iscsi_3 )<br>
order or-raid_start 0: ( iscsi_1:start iscsi_2:start iscsi_3:start )
md_raid:start<br>
order or-raid_stop inf: md_raid:stop ( iscsi_1:stop iscsi_2:stop
iscsi_3:stop )<br>
<br>
That makes it so that when they start up, they start in order, but it
isnt required that every iscsi start before md_raid, just that they try
to start<br>
Then when they stop, its manditory that they stop in that order so that
no iscsi service will stop while md_raid is still running.<br>
<br>
The exception I mentioned is a bug in the policy engine. Bug 2435. The
policy engine allows resources within a colocation set to start on
other nodes. So if I were to stop one of the iscsi services, and then
start it again, it might start on a different node. Unless this bug
gets fixed soon, I'll probably modify the iscsi script so that all the
iscsi devices are under 1 resource.<br>
<blockquote cite="mid:20101214183705.GE30350@rondo.homenet" type="cite">
<pre wrap="">
Thanks,
Dejan
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">I've got 3 iSCSI resources which are in a group, and then an md
raid-5 array as another resource. I have the raid array resource
set to start after the group with a colocation rule, but it will
only start if the whole group comes up. Since this is raid-5, we
can obviously handle some disk failure and start up anyway. So how
do I get it to try to start it up once all the iSCSI resources
have tried to start? Went looking through the docs and didnt find
anything.
Note: there will be other resources in the chain (like mounting
the filesystem) that I dont want to try and start if the raid
array resource didnt start.
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</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
<blockquote type="cite">
<pre wrap="">_______________________________________________
Pacemaker mailing list: <a class="moz-txt-link-abbreviated" href="mailto:Pacemaker@oss.clusterlabs.org">Pacemaker@oss.clusterlabs.org</a>
<a class="moz-txt-link-freetext" href="http://oss.clusterlabs.org/mailman/listinfo/pacemaker">http://oss.clusterlabs.org/mailman/listinfo/pacemaker</a>
Project Home: <a class="moz-txt-link-freetext" href="http://www.clusterlabs.org">http://www.clusterlabs.org</a>
Getting started: <a class="moz-txt-link-freetext" href="http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf">http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf</a>
Bugs: <a class="moz-txt-link-freetext" href="http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker">http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker</a>
</pre>
</blockquote>
<pre wrap=""><!---->
_______________________________________________
Pacemaker mailing list: <a class="moz-txt-link-abbreviated" href="mailto:Pacemaker@oss.clusterlabs.org">Pacemaker@oss.clusterlabs.org</a>
<a class="moz-txt-link-freetext" href="http://oss.clusterlabs.org/mailman/listinfo/pacemaker">http://oss.clusterlabs.org/mailman/listinfo/pacemaker</a>
Project Home: <a class="moz-txt-link-freetext" href="http://www.clusterlabs.org">http://www.clusterlabs.org</a>
Getting started: <a class="moz-txt-link-freetext" href="http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf">http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf</a>
Bugs: <a class="moz-txt-link-freetext" href="http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker">http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker</a>
</pre>
</blockquote>
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