[Pacemaker] Modeling dependencies

[Zrin Žiborski]

Hi there,

I'm browsing through pacemaker documentation and examples for
some days now, but I just do not see if / how it would be possible
to model dependency between resources so that

- unused resources are automatically stopped
e.g. a NFS export needs a mounted file system which itself needs 
underlying RAID device,
* if the export is to be started, the RAID and then the mount have to be 
started first.
* if the export was stopped, then the file system should be unmounted 
and the RAID
device stopped because they are not needed any more.

- there can be a weak dependency: a resource *can use* another resource, 
but it can run without it as well
e.g. a RAID 1 (mirror) would use a block device exported from the other 
node,
but it can run without it (in degraded mode) as well.
* before starting the RAID, the export on the other node should (try to) 
start
* after stopping the RAID, the export should be stopped as well (if running)

Is this possible in (the current version of) pacemaker?
Can rules depend on (meta-) attributes of other resources?

Thank you in advance for hints.
best regards,
Zrin