[Linux-HA] Is this the right config?

Kelly Byrd kbyrd-linuxha at memcpy.com
Mon Oct 1 06:20:12 MDT 2007


>> I have a drbd master/slave resource (ms-drbd1), and then a group
>> (group_vm1). The group contains and filesystem resource (vm1-fs) and my
>> VM
>> (vm1-vm) resource. I have an rsc_order contraint saying group_vm1 should
>> only run where ms-drbd1 has been promoted. I also have a rsc_colocation
>> constraint saying group_vm1 follows ms-drbd1.
>
> You mean the other way around: exchange rsc_order and
> rsc_colocation.
>

I used this XML from the howto page:
<rsc_order id="drbd0_before_fs0" from="fs0" action="start" to="ms-drbd0"
to_action="promote"/>
<rsc_colocation id="fs0_on_drbd0" to="ms-drbd0" to_role="master"
from="fs0" score="infinity"/>


>> Finally I have a location
>> constaint saying ms-drbd1 prefers node1.
>>
>> When testing this with two VMs (add ms-drbd2 and group_vm2, prefering
>> node2), things don't always work out as planned. Sometimes, with only
>> one
>> node running, if I "/etc/init.d/heartbeat start" on node1, ms-drbd1 and
>> group_vm1 will try to migrate over to node1, fail then return back to
>> node2. It's not clear to me what's failing.
>
> What do the logs say?
>

>> Should I be grouping these differently?
>
> The config looks ok to me.
>

I have the impression that I can't put the master/slave drbd resource in
the group with the other two, because it's master/slave-ness isn't the
same as the other two start/stop resources. Is this true?

Basically, I'm looking for how to scale this out easily without a ton of
XML entries for the 22 things I'm managing.




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