[Samba] Migration from Windows to Samba4

[Rob Janssen]

I want to replace a Windows 2003R2 DC by a Samba4 install.

I installed Samba 4.0.10 and successfully joined the Windows domain.
(after applying a small patch to join.py)

The replication works fine, and the new DC now hosts all fileshares and
successfully authenticates users and computers.

Transfer of fsmo roles was also successful.  The old Windows DC is still
active.  I want to decommission it, but when running the Microsoft advised
procedure there are some minor errors that all refer to RPC.

When I try dcpromo it tells me that there is no other reachable DC.
Again complaints about RPC not working.

Is this normal?  Should it go smoothly like the join or are there still some
rough edges in this area?
I could go ahead and remove AD from the Windows machine and then
cleanup manually at the Samba end if required.
Is there a HOWTO for doing that using Samba tools?

Rob