[Pacemaker] Reg. cone and order attributes

[Vladislav Bogdanov]

06.12.2013 07:58, ESWAR RAO wrote:
> Hi All,
> 
> Can someone help me with below configuration??
> 
> I have a 3 node HB setup (node1, node2, node3) which runs HB+pacemaker.
> I have 3 apps dummy1, dummy2 , dummy3 which needs to be run on only 2
> nodes among the 3 nodes.
> 
> By using the below configuration, I was able to run 3 resources on 2 nodes.
> 
> # crm configure primitive res_dummy1 lsb::dummy1 meta
> allow-migrate="false" migration-threshold=3 failure-timeout="30s"
> op monitor interval="5s"
> # crm configure location app_prefer_node res_dummy1 -inf: node3

First that comes to mind is that you should put above line below the
next one and refer app_clone instead of res_dummy1.

> # crm configure clone app_clone res_dummy1 meta clone-max="2"
> globally-unique="false"
> 
> 
> I have a dependency order like dummy2 should start after dummy1 and
> dummy3 should start only after dummy2.
> 
> For now I am keeping a sleep in the script and starting the resources by
> using crm.
> 
> Is there any clean way to have the dependency on the resources so that
> ordering is maintained while clone is run on bot the nodes??
> 
> I have tried with below config but couldn't succeed.
> # crm configure order dum1-BEFORE-dum2 0: res_dummy1 res_dummy2

The same is here.

> # crm configure order dum2-BEFORE-dum3 0: res_dummy2 res_dummy3

So, your example should look like:
# crm configure primitive res_dummy1 lsb::dummy1 meta
allow-migrate="false" migration-threshold=3 failure-timeout="30s"
op monitor interval="5s"
# crm configure clone app_clone res_dummy1 meta clone-max="2"
globally-unique="false"
# crm configure location app_prefer_node app_clone -inf: node3
# crm configure order dum1-BEFORE-dum2 0: app_clone res_dummy2
# crm configure order dum2-BEFORE-dum3 0: res_dummy2 res_dummy3

> Instead of group i used order , so that even if 1 app gets restarts
> others will not be affected.

Yep, advisory ordering is fine for that.

> 
> Also is there any way so that if 1 app fails more than
> migration-threshold times, we can stop all 3 resources on that node??

Maybe advisory colocations can do something similar (I'm not sure)?
http://clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/_advisory_placement.html

You should find correct value for its score (positive or negative)
though. crm_simulate is your friend for that.

> 
> Thanks
> Eswar
> 
> 
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