[Linux-cluster] Service location (colocation)

[Lon Hohberger]

On Sun, Feb 27, 2011 at 06:08:41PM +0200, Budai Laszlo wrote:
> Hi all,
> 
> is there a way to define location dependencies among services? for
> instance how can I define that Service A should run on the same node as
> service B? Or the opposite: Service C should run on a different node
> than service D?
> 

rgmanager doesn't have this feature built-in; you can define
'collocated services' by simply creating one large service comprising
all of the resources for both services.

You could probably trivially extend central_processing mode to do "anti
collocation" (i.e. run on another node).

The 'follow_service.sl' script is an example of how to do part of
'anti-collocation'.   The way it works, it starts service A on a
different node from service B.  If the node running service A fails, it
is started on the same node as service B, then service B is moved away
to another (empty, usually) node in the cluster.

Alternatively, pacemaker supports this functionality.

-- 
Lon Hohberger - Red Hat, Inc.