We've just been bitten by the Samba 4.8 rebase in CentOS/RHEL 7.6, specifically this
bit from the RHEL 7.6 release notes:
"The smbd service no longer queries user and group information from Active Directory
domain controllers and NT4 primary domain controllers directly. Installations with the
security parameter set to ads or domain now require that the winbindd service is
Which stems from the Samba 4.8 release notes:
"Domain member setups require winbindd - Setups with "security = domain" or
"security = ads" require a
running 'winbindd' now. The fallback that smbd directly contacts domain
controllers is gone."
The RHEL 7 Systems Administration Guide now states:
"Red Hat only supports running Samba as a server with the winbindd service to provide
domain users and groups to the local system. Due to certain limitations, such as missing
Windows access control list (ACL) support and NT LAN Manager (NTLM) fallback, the System
Security Services Daemon (SSSD) is not supported."
Now in RHEL 7.5 we were managing to use SSSD with Samba, the only real glitch (we think)
was that SIDs rather than names showing up in the share ACLs. Unfortunately Red Hat
support are sticking to the above like glue so far.
My question to this list is, given the changes to Samba from 4.8, is there a way to get
RHEL 7.6 winbind (for Samba) to use SSSD for the lookups that works?
I noticed that the package sssd-winbind-idmap that ships in RHEL 7.6 contains the library
/usr/lib64/samba/idmap/sss.so which from the idmap_sss man page states:
"The idmap_sss module provides a way to call SSSD to map UIDs/GIDs and SIDs."
With a config example:
idmap config * : backend = sss
(There an open bugzilla and pagure bug about this example being wrong as sss is read
There's also the following file in the package sssd-client
Which is controlled via the alternatives system.
I'm not entirely sure how these differ yet but I get the impression that the intention
somewhere is to re-enable Samba to Winbind to SSSD lookups? Am I on the right track? Could
this be made to work with the versions in RHEL 7.6 if so?
The alternative we're facing is to reset ownership on many millions of files as a side
effect of swapping from sssd to winbind and many open questions as to whether winbind will
handle our active directory (University context, messy). We'd tuned SSSD to finally
work well for us here.