[Pacemaker] live migration and colocation with lvm cloneset issue

[denis bonnenfant]

Le 20/09/2012 00:02, denis bonnenfant a écrit :
> Hi,
>
> I have an issue with live migration of   a xen resource  over a clvm vg :
>
> - a lvm vg (cl_LVM1) cloned resource is defined on both nodes,
> - a xen resource (res_Xen_dns4) is using a lv from vg1, availiable on 
> both nodes,
> - a colocation constraint is defined between domu and vg1
>
> When I try to live migrate res_Xen_dns4 from crm, it stops and 
> restarts cloned instances of vg1, swapping them between nodes ! 
> underlying drbd is demoted... Of course, this operation crashes all 
> the other VMs connected to vg1, and finally all the cluster is fencing...
>
> Maybe I'm completely wrong, but I don't understand this behavior ! I 
> guessed that the colocation constraints were defined with any clone 
> member, and didn't force the clones to move. Did I missed something 
> important ?
>

OK, it seems that live migration implies no ordering/colocation 
constraints.  I saw the serialize option in old threads, but found no 
info in the 1.1 doc.

  So now how can I make my VMs to wait lvm to be available at startup, 
and to start on the node with active lvm (migration threshold ?).
And in the reverse side, what will happen if a node goes to standby ? 
how to ensure that VMs will live-migrate *before* lvm/drbd will be stopped ?

Denis
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