[Samba] Upgrading an old server

[Rowland Penny]

On 05/04/2023 09:59, Tamás Németh via samba wrote:
> Dear All!
> 
>   (As I wrote earlier) I'm working on removing an ancient (3.2.5) SaMBa
> member server from an Active Directory domain, and replacing it with SaMBa
> 4.16.4 running on AlmaLinux 9. The domain controllers are Windows servers,
> and the old SaMBa is joined to the domain with "security = domain" type of
> security (the old NT4 type).
> 
>   I'm afraid once I remove the old server from the domain, there is now way
> back for it, however it will have to be removed, since the new server has
> to have the same name.

I take that everything is hard wired to the old servers hostname and 
yes, once it has gone, it has gone.

> 
>   There are millions of files on the old server with 8bit encoded filenames
> (pre-UTF8) and UIDs and GIDs stored in local files.
> 
>   The new SaMBa server is already running with RID idmap backend, and I've
> probably found a way to rename all files to have UTF-8 names and remap all
> UIDs and GIDs on the files to the new ones, even in POSIX ACLs, and all the
> necessary user and group names do exist on the new server either locally,
> or in the AD.

It would be better if ALL the users and groups were in AD.

> 
>   My question is the following:
> 
> After removing the old SaMBa server from the domain, do I have to remove,
> rename and rejoin the new one, or is there a way to rename it while being
> part of the domain?

Not that I am aware, part of the join involves creating an AD object for 
the computer, so you have to leave the domain, rename the computer and 
then rejoin the domain. (Hint: do not specify 'netbios name' in the 
smb.conf, Samba will set it for you).

> Either way, what is the correct way to change the name
> of a SaMBa member server in a Windows controlled AD domain?

See above.

< What files do I
> have to delete (if any) during the operation?

You will probably have to modify /etc/hostname and /etc/hosts

> Will the RID backend give me
> a 100% guarantee that Linux UIDs and GIDs will remain unchanged on the new
> server during this "rename" process?

Provided you use the same 'idmap config' lines on a Unix domain member, 
the 'rid' idmap backend will always return the same ID's. This is 
because they are calculated from the AD objects RID and the DOMAIN low 
range.

Rowland