Is it possible for FUEL to deploy Openstack with VLAN, but on unmanaged switch.

I have 3 server, [Master], [Controller+Cinder], and [Compute+Cinder]. All of them connected to a router as public interface, and also connected to an unmanaged switch as private/storage/manage/PXE.

In deploy process, the provision went well. The Verify networks on "Connectivity Check" after provision is fine too.

However, the deploy failed at ntp-check with the following message "All nodes are finished. Failed tasks: Task[ntp-check/29] Stopping the deployment process!".

After some investigation , I found that the task dns-client, has edit the /etc/resolv.conf to change the DNS server into an unknow ip address of Management network that I cannot identified the interface with this ip address. Is it a virtual ip? or some ip from inside SDN? The consequence is cannot resolve any url into ip address (can ping 8.8.8.8, but cannot ping http://www.google.com)

Would the problem vanish if I replace the unmanaged switch with the managed one with the right configuration?