Open Stack

Trying to run the training labs from
http://git.openstack.org/cgit/openstack/training-labs, I hit two problems.

First, the showstopper: I get 

ERROR: port is in limbo and won't recover:
{"_date":1448791388943,"Port":{"aa26a099-6644-4a3a-b0e3-ec3de8659598":{"tag"
:4095}},"_comment":"ovs-vsctl: /usr/bin/ovs-vsctl --timeout=10 --oneline
--format=json -- set Port qr-2bd0cc52-07
tag=4095","Open_vSwitch":{"c67ee198-2b9d-4dc4-a0ad-013cd3a39f24":{"next_cfg"
:15}}}
{"_date":1448791389765,"Port":{"209d3eee-9c5d-426f-87c0-0efeffce9ebb":{"tag"
:4095}},"_comment":"ovs-vsctl: /usr/bin/ovs-vsctl --timeout=10 --oneline
--format=json -- set Port qg-9c2afbd1-15
tag=4095","Open_vSwitch":{"c67ee198-2b9d-4dc4-a0ad-013cd3a39f24":{"next_cfg"
:16}}}

in the 038_00_setup_neutron_network.auto log file. It seems that
installation of the network node failed. Where do I start debugging this?

Second, a problem that I can work around by myself but that defeats the
intention of convenient and easy installation. I am unable to ssh into the
any of the three nodes because their eth0 IP addresses aren't reachable. On
my system, they all have the same address 10.0.2.15/24, and I find no trace
of this network in iptables or the routing table. The DHCP server where this
address comes from is 10.0.2.2. I don't know Virtualbox well enough to find
out how it was configured.
Perhaps the KVM network configuration (two networks 10.0.0.0/24 and
10.0.1.0/24) on my system gets into Virtualbox's way. 
Here again - where should I start looking?

Bernd.