[Labs-l] role::mail::(sender|mx) conflict

[Jeff Green]

I'm working on a mailserver instance 'deployment-mx' in beta that we can 
use to test mediawiki mail bounce handling (ref Bugzilla 46640). The 
instance should resemble a production mailserver (e.g. polonium) which 
uses role::mail::mx. I'm blocked because we include role::mail::sender in 
the base labs role, and that conflicts with role::mail::mx. There are many 
ways to fix this, but I'm not very familiar with nova or our 
implementation, and I'm not sure what to do.

To me the most logical approach would be to remove role::mail::sender from 
role::labs::instance, and include/exclude like everything else via the 
instance management UI. But we would probably want it enabled by default 
on new instances, and enabled for instances that exist today, and all that 
takes labs/nova dev time.

Another approach would be to redesign our role::mail::* classes to work 
within the current labs limitations. For example we could configure mail 
based on a global set somewhere (can that be stored in LDAP?) or even by a 
file on the instance itself.

Last/worst approach would be to make the host its own puppetmaster. I'm 
hoping to avoid this.

Help? Ideas?

jg