Sorry, these 2 test nodes was in cluster when with 1.9. But with 2.0, I don't do a cluster as the network do not support multicast. But yesterday, I tried to setup the cluster with 2.0 just to verify that multicast is not working...
I got the same issue with the upgrade script, pmxcfs kept saying "Unable to get local IP address". I checked the configuration and /etc/hosts does have an entry for the name defined in /etc/hostname.
The catch is that /etc/hostname defines a fully qualified domain name (foo.example.com) and it seems pmxcfs doesn't handle this properly. I added the sub domain "foo" in /etc/hosts and now pmxcfs works fine.