[Samba] CTDB Question w/ Winbind

Robert Buck robert.buck at som.com
Tue Oct 6 12:24:22 UTC 2020


Superb. I'll take a look. Thank you

On Tue, Oct 6, 2020 at 1:46 AM Martin Schwenke <martin at meltin.net> wrote:

> Hi Bob,
>
> On Mon, 5 Oct 2020 09:31:59 -0400, Robert Buck <robert.buck at som.com>
> wrote:
>
> > It seems as though, when I go from `clustering = no` to `clustering =
> yes`,
> > if I do a domain join, it will fail. However, if I do a `systemctl
> restart
> > ctdb` (knowing full well it will fail every time), if after this I add a
> > sleep(15), then do a domain join, then do a `systemctl restart ctdb`,
> then
> > the join will have worked, AND CTDB will start properly. So in a
> nutshell,
> > in Ansible,
>
> > - do all the samba setup without clustering on, even winbind setup;
> verify
> > it works
> > - do all the ctdb setup and turn clustering on, but we must again
> > domain-join, but only after having run restart-ctdb once first, then
> after
> > the join, do another restart-ctdb
>
> > Only then does the system come to a stable point.
> >
> > This appears to be the only way to have a repeatable deployment process
> of
> > CTDB over multiple regions globally.
> >
> > Any thoughts or recommendations?
>
> I think we need to document this better.  ;-)
>
> Although we've tried to explain things well in the wiki there are still
> gaps... and this is one of them.   Although some of the tutorials around
> the place are dated they fill in some of these gaps nicely.
>
> So, I'll repeat what Ralph said but with a few more words of
> explanation...  :-)
>
> When clustering is enabled a new set of databases, managed by CTDB,
> replaces those that were being used before.  This means that even if a
> node was previously joined to a domain it will no longer be joined
> after you enable clustering.  The credentials have basically
> disappeared... unless you (immediately?) disable clustering again.
>
> In general, before you enable the 49.winbind and 50.samba event
> scripts, you should start CTDB and join the domain.
>
> Then you can enable those scripts and restart CTDB so it will start the
> services.
>
> Since you mention Ansible, I'll point you at autocluster, which I
> rewrote (last year?) using Vagrant and Ansible.  It is a testing tool
> to generate virtual clusters for (developer) testing of Clustered
> Samba.  It has a lot of clues that need to make their way into
> documentation.  We don't do releases but there is a git repository at:
>
>   https://git.samba.org/?p=autocluster.git;a=summary
>
> Here's the sequence of tasks that we use to configure a "nas" node:
>
>
> https://git.samba.org/?p=autocluster.git;a=blob;f=ansible/node/roles/nas/tasks/main.yml;h=0c444bd77c0a883b1c608fcd6398592be8e962de;hb=73b6a2844e827b4c2c2b5d5946cc14c7c61d7d75
>
> In particular, this file disables the event scripts:
>
>
> https://git.samba.org/?p=autocluster.git;a=blob;f=ansible/node/roles/nas/tasks/generic/ctdb.yml;h=0271d2a11cff0e9359e115f20c5e641e3279c3ea;hb=73b6a2844e827b4c2c2b5d5946cc14c7c61d7d75
>
> and later the domain is joined:
>
>
> https://git.samba.org/?p=autocluster.git;a=blob;f=ansible/node/roles/nas/tasks/generic/ctdb-with-samba-nfs.yml;h=b6f9c6d2354e4922535d9048648df4e9e5161689;hb=73b6a2844e827b4c2c2b5d5946cc14c7c61d7d75
>
> Note that I'm not an Ansible expert and these Ansible playbooks aren't
> necessarily idempotent.  At the moment it all works well enough and I
> hope to get opportunities to clean it up more later.  It is very much
> aimed at developer testing... but it would be cool if a subset of it
> could be used to configure "real" Samba clusters.
>
> However, given that you mentioned Ansible I figure that it might
> document certain things for you nice and clearly.  It isn't missing
> anything obvious because we use it to build several test clusters each
> night.
>
> One day later this week I'll try to take a look at the wiki and add some
> documentation for joining a domain...
>
> peace & happiness,
> martin
>
> --

BOB BUCK
SENIOR PLATFORM SOFTWARE ENGINEER

SKIDMORE, OWINGS & MERRILL
7 WORLD TRADE CENTER
250 GREENWICH STREET
NEW YORK, NY 10007
T  (212) 298-9624
ROBERT.BUCK at SOM.COM


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