Comment 17 for bug 1219795

Attached is a heat stack which will reproduce this all the time.

$ heat stack-create -f 1219795.yaml -P num=30 d1

and then look in instances. You will see some instances have been assigned an IP, and some not.
What has happened is that neutron has allocated an IP to dnsmasq, and then tried to allocate that IP to an instance.

e.g.: the dhcp range is 172.16.0.10-172.16.0.254.

 172.16.0.11 -> i1
 172.16.0.12 -> i2
 172.16.0.13 -> dhcp/dnsmasq
 172.16.0.13 -> i3. FAIL