[Pacemaker] Removing resource from group without disturbing remaining resources in group

[Dejan Muhamedagic]

Hi,

On Thu, Jun 06, 2013 at 04:50:14PM +0200, Florian Crouzat wrote:
> Le 06/06/2013 16:35, Andreas Mock a écrit :
>> Hi all,
>>
>> is there a way to remove a resource from a group without
>> disturbing the other resources in the group.
>>
>> The following example:
>> - G1 has R1 R2 R3
>> - All resources are started
>> - Stopping R1 would cause a stop of R2 R3
>> - So, the idea was:
>> * crm configure edit => remove R1 from the group while running
>> * stop resource
>> * delete resource
>>
>> BUT: At some point (which we couldn't find out at
>> the moment) all remaining resources of the group are
>> restarted. It seems that the change of the implicit
>> dependency tree of the initial group forces a rebuild
>> of that tree including a restart of that group.
>> (Andrew: Is this assumption right?)
>>
>> So, is there are way to add/remove resources from
>> group without disturbing the other resources.
>> It's clear to me that the resources would restart
>> when the node assignment after removing would change.
>>
>> Hints welcome.
>>
>
> Approximative syntax, do not blame me !
>
> * crm configure property maintenance-mode=true
> * crm resource stop R1 # it won't stop as it's in maintenance-mode

A recent crmsh knows that it can delete a resource if
maintenance-mode is set.

> * crm configure delete R1
> * crm configure show # very that all references to R1 are gone
> * crm resource reprobe # the cluster double check the status of declared  
> resources and sees that everything is fine and R1 doesn't exists anymore
> * crm_mon -Arf1 # double check that everything is "started (unmanaged)"  
> and R1 is gone
> * crm_simulate -S -L -VVV # optional, to check what would happen when  
> leaving maintenance-mode
> * crm configure property maintenance-mode=false

Right. The basic idea is to detach the PE while making changes.

Thanks,

Dejan

> If something goes wrong while in maintenance-mode, crm resource cleanup  
> foo might be handy. Nothing should move, start or stop until you leave  
> maintenance-mode anyway. I use this scenario very often, to add or  
> remove IPaddr2 resources to a group of 30+ IPaddr2.
>
>
> -- 
> Cheers,
> Florian Crouzat
>
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