[Samba] fail-over, redundancy, bdc, multi-dc-domain

Adam Tauno Williams awilliam at whitemice.org
Tue Jan 22 12:30:35 MST 2013

On Tue, 2013-01-22 at 10:53 -0800, Gregory Sloop wrote:
> I'm aware of, at least generally, how one would have done a
> BDC/Redundant server under OpenLDAP Samba3.
> However, rolling your own multi-domain-controller was fairly daunting
> [for me] under Samba3 / OpenLDAP.

Yea... that is an understatement.  Replication... OpenLDAP...
<shivers/>.  It was rough, and then they switched to cn=config.  Never
bothered to make a single administrative tool worth @&^@*&@ and
that-one-developer harassed and insulted and was a general @&*%^@*$ to
anyone who tried [including me] - tools are for whimps! [and, you know,
people who have stuff to do, those whimps!].  Sad, OpenLDAP is a really
great project/product.

> I've been very interested in Samba4 for the more integrated nature of
> having LDAP/DNS/Samba all under one roof. [i.e. Fewer places where I
> can screw it up horribly.]

Yep, it does that.  Yay!  

Or you can look at it as one-stop horrible screw up;  kill it, and you
kill everything.

> However I'm also interested in how one can handle fail-over. I don't
> need something totally seamless and "big-iron" style. A backup box
> that would need some manual intervention would be fine.
> So, something like an rsync'd backup box where the shared
> files/accounts/etc are perhaps an hour out of date, and that would
> require 15 minutes to bring up as a primary would be an acceptable
> solution.

It does hot-replication of the SAM (at least).  In theory it does
replication of DNS [if you are using internal DNS] but there might be
some bugs there.  It doesn't replicate the sysvol [yet], you gotta do
that yourself, old-school.

> That's not to say I wouldn't want something better, but that's kind of
> the low end of the "acceptable" scale.

It is above your acceptable out-of-the-box.

> I've done some searches on the list and spent a while looking for
> "examples" but I don't easily find any. [Using searches with: samba4 bdc,
> redundant, backup, etc. There are a ton of very old articles on the
> list, but almost nothing I could find specifically on Samba4.]

Create a DC, add a another DC, done.  Move on.  

> Could some kind soul point me either to:
> 1) Search terms more likely to produce results, or some discussion threads or
> 2) wiki/how-to's on how to accomplish something i the neighborhood on this subjet?
> [Option #2 preferred.]

The Samba4 wiki!  <http://wiki.samba.org/index.php/Samba4>

And you need to read up on Active Directory.

> As a note, I'd be glad to help document this/provide a "here's what I
> did and how", provided it's something reasonable for me to apply to
> the situation I'm referring to - so I'm more than glad to contribute
> back where I can.

Create an account on the wiki.

Adam Tauno Williams  GPG D95ED383
Systems Administrator, Python Developer, LPI / NCLA

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