(please forgive the cross-posting to subscriber-only lists)
Howard Chu helpfully wrote up this summary of the meeting we held at the
CIFS Workshop on how Samba4 should work with an LDAP backend.
The background is that Samba4 increasingly needs some things that an
LDAP server could provide for us. In the short term, we need to add
subtree renames to ldb_tdb, but OpenLDAP's hdb already provides this for
us.
Likewise, we have a desperate need for replication (because any site in
need of Samba4's features will want multiple DCs) - and Fedora DS's
replication seems like a very good, solid answer. (Sadly it doesn't
give us subtree renames...).
Another feature we don't yet do schema validation in Samba4, beyond
checking that the objectClass list is valid. We need to extend that,
but perhaps the LDAP server could do that validation for us?
Finally, in the long term, we would like to have Samba4 play nice in a
multi-use directory, and this presents a schema mapping problem. We
agreed to get together and try and work out a schema that is compatible
to Microsoft's extensions, without being too painful to see from a
traditional client. I hope to put together a discussion on this in the
near future.
I expect we will continue to use and support ldb_tdb as a backend on
Samba4, but for some features (which they will want), users should be
directed to use LDAP as an important backend.
Andrew Bartlett
-------- Forwarded Message --------
From: Howard Chu <hyc@symas.com>
To: OpenLDAP-devel@openldap.org
Subject: [Fwd: LDAP/Samba 4 summary]
Date: Fri, 28 Sep 2007 10:42:22 -0700
Yesterday afternoon at the CIFS Workshop we had a meeting to discuss Samba 4's use
of LDAP going forward, and what obstacles remained. Among the attendees that I can
remember were Andrew Bartlett, Andrew Tridgell, Simo Sorce, Stefan Metzmacher, and
(one more, I've forgotten the name) from the Samba team. Nicole Jacque and another
(sorry, don't remember the name) from Apple/OpenDirectory, Pete Rowley from
FedoraDS, and myself and Marty Heyman for OpenLDAP and Symas.
The upshot is that both the Samba and the LDAP sides have work to do, but there
are no major roadblocks. LDAP will be Samba 4's default/recommended data store. As
for OpenLDAP, most of what Samba 4 needs is either already implemented, or in
progress.
Schema design tends to still be a stumbling block; in a separate conversation we
discussed some design issues in MIT's new Kerberos schema as well as missing
features in Heimdal's existing Kerberos schema. That's a bit outside this
openldap-devel scope but I've committed to working with the Samba and Kerberos
communities to draft some changes to unify these two Kerberos schemas.
-------- Forwarded Message --------
From: Howard Chu <hyc@symas.com>
To: Andrew Bartlett <abartlet@samba.org>
Subject: LDAP/Samba 4 summary
Date: Thu, 27 Sep 2007 22:41:23 -0700
Missing features / wishlist
bitwise ops.
already in OpenLDAP, recently added to FedoraDS(?)
USNs
partially implemented in OpenLDAP, need more complete spec
LDAP Transaction support
draft-zelenga-ldap-txn - partially implemented in OpenLDAP
some concerns because Samba's definition of transaction is
not the
canonical ACID definition. More like ACI, no Durability
guarantee, doesn't
play well with LDAP Multimaster Replication. We all agreed that
if Samba
doesn't care, neither do we. All that matters is that it
provides tidy,
painless rollback in event of intermediate failures.
Access Controls
my suggestion re: OpenLDAP - we support modular ACL
engines, we should
just write a module for native NT ACLs in OpenLDAP
AD schema - we agreed that a new schema is necessary no
matter how you
slice it, we will all collaborate to define a superset of AD
that everyone can
support.
Authentication mechanisms - generally Samba will handle this
itself
validation - Samba4 + LDAP must pass everything under Samba's
"make test"
suite.
Transactions again - we may need things like memberOf and
other linked
attributes to be managed internally in the server. No problem,
both OpenLDAP
and FDS have memberOf plugins already available.
Subtree renames - MS tools assume subtree renames work.
Supported in
OpenLDAP already (back-hdb, back-ldif, will be in back-tdb).
Unfortunately not
supported in FedoraDS, might be able to kludge it, but it will
require
additional mapping layers. And kludging will break base-scope
searches,
referential integrity, etc...
--
Andrew Bartlett http://samba.org/~abartlet/
Authentication Developer, Samba Team http://samba.org
Samba Developer, Red Hat Inc. http://redhat.com
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