[drbd-mc] NullPointerException in certain cluster configurations

[Lars Ellenberg]

On Fri, Feb 12, 2010 at 09:18:47AM +0100, Peter Luciak wrote:
> Rasto Levrinc  wrote / napísal(a):
> >>colocation apps_on_drbd_app inf: apps ms_drbd_app:Master
> >>colocation apps_on_drbd_data inf: apps ms_drbd_data:Master colocation
> >
> >Do you actually need this two colocation rules? "apps" are already
> >colocated through the colocation with "fs" group. Without these two
> >colocations the DRBD-MC would work, not that I don't have to fix my bug.
> >:)
> 
> 
> Sure, but then when I migrate "apps" resource, the colocated "fs"
> resource is migrated, but the underlying DRBD resources aren't
> switched. Probably I need another order rule somewhere...
>

That may be because you got one of your colocation rules upside down ;)

...
order apps_after_fs inf: fs apps
order fs_app_after_drbd_app inf: ms_drbd_app:promote fs:start
order fs_data_after_drbd_data inf: ms_drbd_data:promote fs:start

colocation fs_app_on_drbd_app inf: fs ms_drbd_app:Master
colocation fs_data_on_drbd_data inf: fs ms_drbd_data:Master

Those are ok.

colocation fs_with_apps inf: fs apps

But this one is wrong:
You don't colocate the file system with the apps.
But you colocate the apps with the file system.

There is a difference between "rsc" and "with-rsc".
You cannot place the file system relative to apps,
if apps depend on fs.

http://www.clusterlabs.org/doc/en-US/Pacemaker/1.0/html/Pacemaker_Explained/s-resource-colocation.html

So make that
colocation apps_with_fs inf: apps fs

Then these two should not be necessary:
colocation apps_on_drbd_app inf: apps ms_drbd_app:Master
colocation apps_on_drbd_data inf: apps ms_drbd_data:Master


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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