ctdb event scripts

[Martin Schwenke]

On Fri, 11 Nov 2016 10:43:32 -0600, Steve French <smfrench at gmail.com>
wrote:

> On Thu, Nov 10, 2016 at 7:39 PM, Martin Schwenke <martin at meltin.net> wrote:
> 
> > On Thu, 10 Nov 2016 19:06:50 -0600, Steve French <smfrench at gmail.com>
> > wrote:
> >  
> > > ctdb event scripts are run automatically - but sometimes for debugging it
> > > would be useful to run one or more scripts (at least the monitoring part  
> > of  
> > > them) manually with output displayed to stdout.  Has anyone experimented
> > > with doing this?  
> >
> > You should be able to run an event script by hand and give "monitor" as
> > an argument.
> >
> >  
> 
> That works and is useful - but dumps to a log so a little harder to read
> for quick checks.

Oh, I didn't mean "ctdb eventscript monitor".  I meant something like:

  /etc/ctdb/event.d/50.samba monitor

There is enough boilerplate in the scripts so that they can find the
functions file and the configuration.

CTDB won't notice that you're running it, unless it stores state and a
subsequent run by CTDB uses that state.  For example, 60.nfs counts
RPC failures before failing the "monitor" event.  If you run a script by
hand it will update the same state.

Alternatively, if you just want to know why a monitor cycle failed
without grovelling through logs, you can always see the output of the
last monitor cycle by running:

  ctdb scriptstatus monitor

Cool feature idea: implement an option to scriptstatus that shows the
output of the last failure.  This would require daemon support, since
that's where the information comes from.

peace & happiness,
martin