I know, this does not fit in the cloud operator model nor the openstack-neutron way of doing things.

However, i have this use case:

- vmware is booting guest vm with underlying DHCP server for IPAM integrated with DNS for host registration as the guest vms power on. So, vm gets ip with its hostname DNS registered as it boots.

-  I started a few vms on openstack, I can attach guest vms on these provider n/w and I can see they are reachable just like any other vm on an enterprise network similar to vmware guest vms and this is great. However, I cannot find any docs, option where these guest vms can cross over to external DHCP for ip address management because the provider network operates at Layer3.

Found this blueprint, review discussion

 https://blueprints.launchpad.net/neutron/+spec/dhcp-relay 
Which is close to what i'm looking for and not updated for sometime. 

Wanted to know if anyone has come across this scenario and how to get over this.  

As one of the options, validated openstack-designate service which solves the hostname registration not the IPAM. Also it needs site DNS server domain management .

Something, I can look at if the external DHCP server is not an option for nova boot. 

Thanks,

Swamy