[Pacemaker] resources not migrating when some are not runnable on one node, maybe because of groups or master/slave clones?

[Phil Frost]

On 07/29/2012 11:15 PM, Andrew Beekhof wrote:
> If I run:
>
> tools/crm_simulate -x ~/Dropbox/phil.xml -Ss | grep "promotion score"
>
> I see:
>
> drbd_exports:1 promotion score on storage02: 110
> drbd_exports:0 promotion score on storage01: 6
>
> The 100 coming from one of your rules which says:
>
>             <!--# storage02 is a much more capable machine, so prefer that.-->
>
> So I'm not really understanding why you think we'd migrate everything
> to storage01.

Because of the colocation rules:

(ip_storage vg_exports) -> drbd_exports_ms
nfs_kernel_server_clone -> nfs_common_clone -> portmap_clone
export_test -> fs_test -> vg_exports
export_test -> nfs_kernel_server_clone

export_test must be on nfs_kernel_server_clone, and also the DRBD master 
(indirectly, through fs_test -> vg_exports -> drbd_exports_ms). But, 
storage02 can't run nfs_kernel_server_clone (location foo).

I know the rules are complicated, but I couldn't find a simpler 
configuration that still showed the problem. They make sense if you 
consider the services they represent though:

- to make an export, you need an NFS server and a filesystem mounted
- to mount a filesystem, you need the volume group, and therefore need 
to be the DRBD master