There are times where it can be handy to test an undercloud install in a standalone VM. For example, if you're working on installing a new service, or upgrading the undercloud, many times you can make progress in a lighter weight single VM environment. Obviously the undercloud won't be usable for anything if it's not part of a full virt environment, but you can at least check that a service is running at the end of the install and do some basic sanity checks.
It's not terribly difficult to do this. The biggest hurdle to overcome is the fact that most VMs only have a single network attached, and the undercloud install requires at least two. To get around this, create a dummy interface:
sudo ip l a dummy0 type dummy
sudo ip l set dummy0 up
You could also name this eth1 so it matches the default undercloud configuration, but I like the explicit reminder that it is a fake interface.
Then you can fire up the Undercloud Configuration Wizard or edit undercloud.conf by hand and set the provisioning interface (local_interface) to dummy0. With that done, you should be able to run the rest of the undercloud install as normal.
