samba - May 2024 - winbind: does it actually depend on nmbd? and network-online?

Hi!

In packaging/systemd/winbind.service, there's this ordering:

After=network.target nmb.service

Does winbind really need nmbd running?

Another interesting dependency here.  nmb.service (in the same directory) has

Wants=network-online.target
After=network.target network-online.target

Note nmbd needs network to be online.  While winbind only needs
network to be up.  If winbind requires nmbd, who in turn requires
network to be online, winbind will be started only with online
network.  If we drop winbind dependency on nmbd here, winbind will
be started earlier, before network is online.

Does winbind requires network to be online or just up?
I *guess* in order for winbind to be useful, network should be online,
or else it wont be able to resolve names.  On the other hand, it keeps
internal cache so once a user is looked up, winbind can return this
user from the cache without network being up.

FWIW, requiring network.target doesn't really give us much: if it needs
just basic tcp/ip to be able to bind to all-zeros address, loopback iface
is being configured much earlier than any other services.  On the other
hand, if it needs particular interfaces to be up, it should depend on
these interfaces, - after network.target is available, there's no guarantee
that all interfaces are configured.

Thanks,

/mjt

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On Thu, 2 May 2024 13:44:47 +0300
Michael Tokarev via samba <samba at lists.samba.org> wrote:
> Hi!
> 
> In packaging/systemd/winbind.service, there's this ordering:
> 
> After=network.target nmb.service
> 
> Does winbind really need nmbd running?
Well, no and yes ;-)

No, if you are running Samba as an AD Unix domain member without SMBv1
(in which case, you do not need nmbd at all), but if you are still
running an NT4-style domain, then you need nmbd to provide NetBIOS
Browsing.
> 
> Another interesting dependency here.  nmb.service (in the same
> directory) has
> 
> Wants=network-online.target
> After=network.target network-online.target
> 
> Note nmbd needs network to be online.  While winbind only needs
> network to be up.  If winbind requires nmbd, who in turn requires
> network to be online, winbind will be started only with online
> network.  If we drop winbind dependency on nmbd here, winbind will
> be started earlier, before network is online.
> 
> Does winbind requires network to be online or just up?
No idea about that, perhaps Jeremy will know.

Rowland