[Linux-ha-dev] Re: [DRBD-user] drbd peer outdater exit codes [drbd ocf floating peers not working. don't try]

Lars Marowsky-Bree lmb at suse.de
Fri Sep 12 22:27:27 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On 2008-09-12T22:15:41, Lars Ellenberg <lars.ellenberg at linbit.com> wrote:

> > That's simply not true. It works, but it does not work with dopd. That
> > is a difference. ;-)
> and it does not work with _any_ handler.
> by default, starting with 8.2.6 iirc,
> we call the "before-resync-target" handler,
> whether that is configured or not,
> before we become sync target.
> if that does not know what node it is,
> it will return != 0.
> so resync (and connection) is aborted.

Ah, right; I admit I was thinking drbd 0.7, not drbd8. Indeed, drbd8 has
the restrictions you mention.

But I'd really like to get this kind of functionality for drbd8 too.

> the problem is to pretend to be someone which you are not,
> and rely on the fragile hope that either no-one cares,
> or that impersonation would somehow be propagated.

Well, it worked for the use case we had.

> > listen to the notifications we provide, and infer the peer state by that
> > means ... ;-)
> yeah.  I asked you before,
> how exactly that would look like,
> and so far I saw only handwaving.

Hm, I don't think there was hand-waving. Sorry. What was unclear?

You get notifications when the peer starts or goes down (or is fenced,
which looks the same). This is not yet relayed to drbd internally (just
the RA gets the notification so far), but we could, for example, call
"standalone" explicity to disconnect; we can discuss this mechanism.

When drbd loses the peer internally, but w/o us providing the
notification, it's either the replication link crashed, or fencing
failing or loss of quorum; anyway, you'd "outdate" yourself (and freeze
io) until this notification was provided (which of course needs to be
persistent across reboots).

Wouldn't that work?

> tell me how to get that done using "higher level"
> heartbeat/crm/pacemaker constructs, and I'm happy to do that.

Yes, sorry if that wasn't clear, and this is a good discussion to have.
I was very busy in the last few weeks, and apologize if I dropped the
ball somewhere.


Teamlead Kernel, SuSE Labs, Research and Development
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

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