Upgrade path options with 2 DC's with differing releases

[Michael Croes]

Dear list,

Since a while I've been running a Samba 4 alpha 13 server (from Ubuntu
Maverick). This is the starting point of my domain. After a while I
added a Samba 4 alpha 15 server as second DC, but I never ran
upgradeprovision. This worked, although I always kept using the alpha
13 server as primary server. Now recently I upgraded the alpha 15
server to alpha 17, and ran samba-tool dbcheck. This did make a lot of
changes, but failed to complete a few outstanding issues. Later on I
learned I needed to do upgradeprovision, but that fails because I have
no winbind on the alpha 17 server and adding winbind crashes samba.

So what I have now is an alpha 13 server and an alpha 17 server, but
my database is somewhere in between. I can dive into the winbind issue
on alpha 17, but I guess it's almost irrelevant and just occurs
because of my 'broken' database.

Now I'm wondering what my options are. I can't upgrade the alpha 13
machine because it's always in use, but I can copy the database to a
virtual machine, perform the upgrade there and upgrade the physical
machine when everything works, which makes this the closest option to
a normal upgrade path.

I also have the database from the second DC from when it was at alpha
15. However, is it actually a good idea to perform a database upgrade
on anything but the first DC? If I do so, will the first DC with alpha
13 work properly, or should I make sure both DC's are at the same
version to start with?

Also, when the upgrade is done, the alpha 17 machine (the physical
one) needs to become the primary DC at some point, but I'm not sure if
that matters right now...
Regards,

Michael