[Pacemaker] Master Slave

[Dan Frincu]

First take a look at this 
http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
It contains all you need for this kind of setup. I'm not aware if the 
M/S relationship extends to other resources than DRBD, but in this case 
you don't actually need a M/S relationship (from my point of view).

1. Read in the document above about 'symmetric-cluster'
2. Based on results from point 1, set the resources as being allowed 
either to run anywhere or not, and add location constraints for each 
primitive.
3. Define mandatory ordering constraints for the mysql primitive, with a 
higher priority on the node you wish to use as a Primary node and a 
lower priority on the Secondary node (if Primary node fails, the 
resource will failover to Secondary node)
4. Define colocation so that VIP will always run where the mysql 
resource runs.
5. (optional) define mail alerts when resource failure occurs, define 
what the mysql resource should do when the Primary node recovers, should 
it remain on the Secondary node and be manually moved, should it go back 
to the Primary node by itself, these are things you might want to 
consider, but are not mandatory to the question asked, therefore the 
"optional" at the beginning)

Regards,
Dan

Freddie Sessler wrote:
> I have a quick question is the Master Slave setting in pacemaker only 
> allowed in regards to a DRBD device? Can you use it to create other 
> Master Slave relationships? Does all resource agents potentially 
> involved in this need to be aware of the Master Slave relationship? I 
> am trying to set up a pair fo mysql servers One is replicating from 
> the other(handled within mysql's my.cnf.) I basically want to fail 
> over the VIP of the primary node to the secondary node(which also 
> happens to be the mysql slave) in the event that the primary has its 
> mysql server stopped. I am not using DRBD at all. My config looks like 
> the following. 
>
> node $id="0cd2bb09-00b6-4ce4-bdd1-629767ae0739" sipl-mysql-109
> node $id="119fc082-7046-4b8d-a9a3-7e777b9ddf60" sipl-mysql-209
> primitive p_clusterip ocf:heartbeat:IPaddr2 \
> params ip="10.200.131.9" cidr_netmask="32" \
> op monitor interval="30s"
> primitive p_mysql ocf:heartbeat:mysql \
> op start interval="0" timeout="120" \
> op stop interval="0" timeout="120" \
> op monitor interval="10" timeout="120" depth="0"
> ms ms_mysql p_mysql \
> meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1"
> location l_master ms_mysql \
> rule $id="l_master-rule" $role="Master" 100: #uname eq sipl-mysql-109
> colocation mysql_master_on_ip inf: p_clusterip ms_mysql:Master
> property $id="cib-bootstrap-options" \
> stonith-enabled="false" \
> no-quorum-policy="ignore" \
> start-failure-is-fatal="false" \
> expected-quorum-votes="2" \
> symmetric-cluster="false" \
> dc-version="1.0.9-89bd754939df5150de7cd76835f98fe90851b677" \
> cluster-infrastructure="Heartbeat"
> rsc_defaults $id="rsc-options" \
> resource-stickiness="100"
>
>
> What's happening is that mysql is never brought up due to the 
> following errors:
>
> ul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: native_color: 
> Resource p_mysql:0 cannot run anywhere
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: native_color: 
> Resource p_mysql:1 cannot run anywhere
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: 
> native_merge_weights: ms_mysql: Rolling back scores from p_clusterip
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: master_color: 
> ms_mysql: Promoted 0 instances of a possible 1 to master
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: native_color: 
> Resource p_clusterip cannot run anywhere
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: info: master_color: 
> ms_mysql: Promoted 0 instances of a possible 1 to master
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: notice: LogActions: 
> Leave resource p_clusterip (Stopped)
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: notice: LogActions: 
> Leave resource p_mysql:0 (Stopped)
> Jul 22 16:15:07 sipl-mysql-109 pengine: [22890]: notice: LogActions: 
> Leave resource p_mysql:1 (Stopped)
>
>
> I thought I may have overcome this with my location and colocation 
> directive but it failed. Could someone give me some feedback on what I 
> am trying to do, my config and the resulting errors?
>
> Thanks
> F.
> ------------------------------------------------------------------------
>
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>   

-- 
Dan FRINCU
Systems Engineer
CCNA, RHCE
Streamwide Romania

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