Comment 29 for bug 1418921

> First of all there are no clear evidences that dnsmasq assigns the same IP to different clients.

Of course there are, This is why dhcp-sequential-ip option option was add to Fuel in 6.0.

Just use this MACs:
0c:c4:7a:1d:91:64
0c:c4:7a:1d:93:da

0c:c4:7a:1d:90:fe
0c:c4:7a:1d:92:76

and start simultaneously all VMs. dnsmasq will assign the same IP to both pairs. If you start VMs one by one it will be ok because VM will send DHCPACK to dnsmasq and IP will be reserved.
It was debuged in https://bugs.launchpad.net/fuel/+bug/1378000