The immediate use case I have in mind is to support this:
http://wiki.openstack.org/**PackageConfigForNova<http://wiki.openstack.org/PackageConfigForNova>. That design requires periodic checkins between an instance agent and a
nova driver. It certainly /could/ be implemented using ssh, but I
originally wrote the design imagining there was a ready-made, standard
communication service, and I still think it would be convenient.
My concern with that proposal is that it starts simple enough, but then
when you want to know e.g. "was the package installed successfully? is the
service healthy?" then you need more and more complexity i.e. you end up
with PlatformLayer, RedDwarf, Heat, Puppet, Chef or Juju. So putting a
small piece of the required functionality into nova doesn't address your
actual use case, which is "I want configured machines, not just the stock
images". It's probably easier to put that logic into your management
system of choice, so nova shouldn't do it. Am I off base here?
