[PATCH] CTDB recovery lock with arbitrary cluster mutex

[Ralph Boehme]

On Tue, Apr 26, 2016 at 01:45:40PM +1000, Martin Schwenke wrote:
> [Resending from correct address...can moderators please drop the other one?]
> 
> The attached patch set changes the CTDB recovery lock so that it can be
> implemented using an arbitrary, external cluster mutex helper.  At the
> configuration level this looks like:
> 
>   CTDB_RECOVERY_LOCK="!/path/to/my/cluster/mutex/helper [arg ...]"
> 
> Without the leading '!' CTDB continues to use the setting as the name
> of a recovery lock file, which is passes to the provided fcntl(2) lock
> helper.

would it make sense to use a scheme similar to KRB5CCNAME? Eg

CTDB_RECOVERY_LOCK="/path/to/file"
CTDB_RECOVERY_LOCK="FILE:/path/to/file"
CTDB_RECOVERY_LOCK="EXTERNAL:/path/to/external_program"

Cheerio!
-slow