Re: [Nagios-db-devel] neb startup revisited

[Matthew K. <mk...@ma...>]

On Thu, 2005-27-01 at 09:55 -0800, Ben wrote:
> On Wed, 26 Jan 2005, Matthew Kent wrote:
> 
> > In restart.sql (during nagios startup) I'm not quite clear on why an
> > existing host and service should be reset back to a pending state by
> > setting has_been_checked = FALSE. If you look at nagios and the standard
> > cgis during startup, the data is read in from the retention file and the
> > previous states for hosts/services is assumed to be correct.
> 
> Well, technically, the check *is* pending. I understand that the retention 
> file says the host or service has a certain state, but that hasn't been 
> verified. If nagios was simply restarted, then the retention data is 
> likely accurate. But after a restart, it's entirely possible that nagios 
> might have been down for days, and in that case the retention data is much 
> more questionable. 
> 
> Frankly, I think it makes a lot more sense to label everything as pending 
> until it's been checked. Weren't you the one that convinced me of that? :)
> 

My apologies, I wasn't thinking clearly as to what the effect would be
on the tac display. The current implementation is the most accurate.

> > Also in restart.sql, I'm not sure about inserting the empty host/service
> > when one isn't found in the database. For example if you clear out the
> > database and start nagios up the tac display will show X hosts with flap
> > detection/notifications etc disabled which will slowly count backwards
> > as all the checks complete. Kinda funky :)
> 
> Yeah, that's a serious hack. However, I'm not sure how else to record
> services for a new host that has yet to be checked, because if there isn't
> a placeholder record, then the service cannot be entered into the 
> database. Perhaps I should set the host options to null, or some other 
> "unknown" state.
> 
> > As I see it the solution for both issues would be to
> > 
> > - set configured = false for all hosts/services
> > - do the 'select into thisHostID id FROM host WHERE name = hostName;'
> > 
> > if 
> > the host/service is NOT found, send the object to processStatus like
> > 
> > /* update this host */
> > nebstruct_host_status_data ds;
> > ds.object_ptr=(void *)hl;
> > 
> > processStatus(NEBCALLBACK_HOST_STATUS_DATA, (void*)&ds);
> > 
> > which will set configured = TRUE, update the has_been_checked field etc.
> > else
> > we set host/service configured = true and assume the rest of the data in
> > the db is correct and leave it alone (save the extra resources of
> > running the stored proc)
> 
> I think a better idea would be to change configure_host() and
> configure_service() to take in all the data we have on the host/service
> before it gets checked, so that we can make our placeholder records more 
> accurate.
> 

Sounds good. Is passing everything to configure_host/configure_service
instead of just throwing it at processStatus to save processing time or
just a logical seperation?

> > Come to think of it at this point you could actually 
> > delete from host,service where configured = false 
> > to prune any hosts that have been removed from the config.
> 
> I can't support deleting unconfigured hosts, because one of the
> requirements my company has is to be able report on historical
> availablity, even if the host isn't used anymore.
> 

Was thinking about that too, if you removed a host (and maybe went to
add it back later) you might be annoyed to find all the history had
disappeared. I'll remove this from the mysql module and put a note about
adding a db_cleanup.php down the line so users can do it themselves.

> > This should give a more immediate overview of nagios's status right
> > after startup.
> 
> Like I said, I think showing most things in a pending state shows the most 
> accurate status. Well, actually, I suppose marking things as "Pending 
> (assumed up)" or "Pending (assumed down)" and such would be the most 
> accurate, but that could get messy.
> 

Yeah, hardly worth the effort.

Oh and did you get that other email about use of
current_notification_number (it being defined in the schema but not
referenced by the stored procs)? I'm not getting anything from the
mailing list today.

Thanks,
-- 
Matthew Kent \ SA \ bravenet.com