[Pacemaker] advisory colocation constraint group->service

[Andrew Beekhof]

On Thu, Oct 30, 2008 at 10:49, Andreas Kurz <andreas.kurz at linbit.com> wrote:
> On Wednesday 29 October 2008 15:56:13 Andrew Beekhof wrote:
> .....
>>> --- cib_group-res-constr.orig.xml    2008-10-29 11:09:47.000000000 +0100
>>> +++ cib_group-res-constr.xml 2008-10-29 11:26:13.000000000 +0100
>>> @@ -265,7 +265,7 @@
>>>        <rsc_colocation id="bgp-upc-colocate-with-ip_upc"
>>> from="service_bgp-upc" to="service_ip_upc" score="INFINITY"/>
>>>        <rsc_order id="bgp-telekom-after-ip_telekom"
>>> from="service_bgp-telekom" type="after" to="service_ip_telekom"
>>> score="0"/>
>>>        <rsc_colocation id="bgp-telekom-colocated-with-ip_telekom"
>>> from="service_bgp-telekom" to="service_ip_telekom" score="INFINITY"/>
>>> -       <rsc_colocation id="bgp-upc-colocated-with-bgp_telekom"
>>> from="service_bgp-upc" to="service_bgp-telekom" score="1"
>>> symmetrical="true"/>
>>    ^^^^^^^^^^^
>> > My intention for this (^) was to loosely couple them together so
>> > they run
>> > together on the same host. If I decide to stop one of them  and
>> > restart it
>> > after a while it should be colocated again with its "partner" ... if
>> > i decide
>> > to migrate only one of the  two resources to another node the other
>> > resource
>> > should stay where it is running.
>>
>> This is not at all related what symmetrical does.
>> Symmetrical was a work-around for a problem a long time ago and no-one
>> should be setting it to true.
>
> Aaah ... good to know ;-) ... so explicitely creating an extra advisory
> colocation constraint in the opposite direction is the way to go?


No no no.
Dont create dependancy loops - it doesn't achieve anything at all.

They'll always move together anyway.


>> The following patch makes your scenario behave, I just need to run it
>> through the regression tests.
>
> Great, thanks Andrew! ... will this patch be available in Heartbeat 2.1.4?

No.  2.1.4 is already out and there will b eno 2.1.5.
You'll need to swith to pacemaker.