2013.07.22. 4:57 keltezéssel, Andrew Beekhof írta:
On 20/07/2013, at 7:18 AM, Lars Ellenberg <lars.ellenb...@linbit.com> wrote:
On Fri, Jul 19, 2013 at 04:49:21PM +0200, "Tomcsányi, Domonkos" wrote:
Hello everyone,
I have been struggling with this issue for quite some time so I
decided to ask you to see if maybe you can shed some light on this
problem.
So here is the deal:
I have a 4-node cluster, from which 2-2 nodes belong together.
In ASCII art it would look like this:
-------------- --------------
| NODE1 | -- | NODE 2 |
-------------- --------------
| |
| |
| |
-------------- --------------
| NODE 3 | -- | NODE 4 |
-------------- --------------
Now the behaviour I would like to achieve:
If NODE 1 goes offline its services should get migrated to NODE 2
AND NODE 3's services should get migrated to NODE 4.
If NODE 3 goes offline its services should get migrated to NODE4 AND
NODE1's services should get migrated to NODE 2.
Of course the same should happen vice versa with NODE 2 and NODE 4.
The services NODE1 and 2 are the same naturally, but they differ
from NODE 3's and 4's services. So I added some 'location'
directives to the config so the services can only be started on the
right nodes.
I tried 'colocation' which is great, but not for this kind of
behaviour: if I colocate both resource groups of NODE 1 and 3 only
one of them starts (of course, because colocation means the
resource/resource group(s) should be running on the same NODE, so my
location directives kick in and prevent for example NODE 3's
services from starting on NODE 1).
So my question is: is it possible to define such behaviour I
described above in Pacemaker? If yes, how?
You may use node attributes in colocation constraints.
So you would give your nodes attributes, first:
crm node
attribute NODE1 set color pink
attribute NODE3 set color pink
attribute NODE2 set color slime
attribute NODE4 set color slime
crm configure
colocation c-by-color inf: rsc_a rsc_b rsc_c node-attribute=color
I had totally forgotten about that feature :-)
What a good idea!
The "implicit default" node-attribute is #uname ...
so using "color" the resources only need to run on nodes with the same
value for the node-attribute "color".
Lars
--
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com
DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
_______________________________________________
Pacemaker mailing list: Pacemaker@oss.clusterlabs.org
http://oss.clusterlabs.org/mailman/listinfo/pacemaker
Project Home: http://www.clusterlabs.org
Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
Bugs: http://bugs.clusterlabs.org
Hi Lars,
Thank you for your answer, but I still don't really understand how it
relates to my problem. As far as I understand this would give me an
easier way to attach my services to a certain group of nodes, but this
one I already achieved using 'location' directives like this:
location HTTPS_ONLY_ON_HTTPS_NODES HTTPS_SERVICE_GROUP 100: https1
location HTTPS_ONLY_ON_HTTPS_NODES2 HTTPS_SERVICE_GROUP 50: https2
location NEVER_RUN_HTTPS_ON_VPN_NODES HTTPS_SERVICE_GROUP -inf: vpn1
location NEVER_RUN_HTTPS_ON_VPN_NODES2 HTTPS_SERVICE_GROUP -inf: vpn2
Certainly your solution is more sophisticated, but my main problem still
remains if I understand everything correctly, but correct me if I'm wrong.
Anyway, thank you for the idea!
Domonkos
_______________________________________________
Pacemaker mailing list: Pacemaker@oss.clusterlabs.org
http://oss.clusterlabs.org/mailman/listinfo/pacemaker
Project Home: http://www.clusterlabs.org
Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
Bugs: http://bugs.clusterlabs.org
