[Samba] 4.7.x -> 4.9.x upgrade

[Rowland Penny]

On Thu, 14 Feb 2019 11:56:59 -0800
Gregory Sloop via samba <samba at lists.samba.org> wrote:

> >> Does this apply if, instead of an upgrade, one provisions a new DC
> >> on, say, 4.9 and joins it? In short, will this allow you to get
> >> your DCs to 4.9 by creating new DC's on 4.9, and then
> >> demote/remove all the 4.7 DC's after the new 4.9 DC's are synced
> >> etc?
> 
> RPvs> I do not know, I personally never tried it, but even if it does
> RPvs> work, it isn't going to help all those who upgrade via distro
> RPvs> packages, they seem to expect it to work ;-)
> 
> RPvs> Rowland
> 
> I am not reassured that we aren't sure that 4.7.x DC's will
> communicate with 4.9.x DC's and allow a full transfer of roles -
> provided I've read/understood what you wrote in the reply.

My thinking is that the problem is the GUID index mode that went in at
4.8.0. this caused problems from the start and Samba wasn't really
usable until 4.8.2. I think the problem is that a 4.7.x DC doesn't have
the GUID mode in AD and when you upgrade directly, AD doesn't have it,
but 4.9.x expects it. If you add a 4.9.x DC, AD should be upgraded
> 
> Am I misunderstanding things? If there are substantial interop
> problems between versions of Samba, is this documented somewhere. I
> guess I was assuming that given some recent version of Samba, it
> would sync with any other current version of Samba and allow the FSMO
> roles to be transferred.

There is a bug report:

https://bugzilla.samba.org/show_bug.cgi?id=13760

> 
> And yes, I get that doesn't really solve the distro upgrade problem,
> but if it was a given that you could spin up a new DC and sync, then
> transfer FSMO roles - well that would go a long way to assuring a
> reasonable way around the problem. (At least until a good
> understanding of the problem was wide-spread and a solution found.)
> 
> Please tell me I've misunderstood this! :)

Sorry, but you haven't, if you upgrade directly from 4.7.x to 4.9.x, it
doesn't work :-(

I will spin up a 4.7.x DC tomorrow and then join a 4.9.x Samba to it
as a DC, lets see what happens.

Rowland