mclt Values, was 2 Instances of dhcp on Same Platform

[David W. Hankins]

On Mon, Feb 26, 2007 at 10:03:28AM -0600, Martin McCormick wrote:
> 	If omapi can add and delete those dynamic entries, I can
> certainly revise what our home-grown IP-number management system
> does and it would end up actually being much less complex than it
> is now.  We rarely ever would need to bring either server down if
> we could use omapi to add and delete those static addresses.

I'd hate to recommend using OMAPI as I know how painful it is to
use it effectively.  I also have no plans to perpetuate it.

But it can absolutely do the thing you describe today, which is
at least better than the vaporous alternative I'd rather we had.

> If you can use omapi to continuously make static adds and deletes,
> do they end up in dhcpd.leases?

Yes, the difference so far as I know is the presence of a 'dynamic;'
keyword to differentiate them (the same parser is used for leases
and config).

> If so, I could write a master
> load script that puts them there and then leaves them out of
> dhcpd.conf.   I assume many other sites have the same issues, but
> I do apologize for the length of this message.

There's something of an issue waiting to rear its head here,
which is how to synchronize a known list of what should be the
running state with dhcpd.leases.

For example, I've had failover customers report problems with
"rogue dhcp servers NAKing clients randomly", only to find that
it was due to rebuilding one of the pair of servers (lost and
restarted dhcpd.leases) without re-populating from scratch all
of the OMAPI events.

The problem I guess is that it's hard to compare stuff you put
into OMAPI with stuff you'd like to make sure had been put into
OMAPI.

I think the model really needs to change where the config state
is somewhere external to dhcpd (but still dynamically updated).

A startup pull with a runtime push.

-- 
ISC Training!  http://www.isc.org/training/  training at isc.org
Washington DC area, April 16-20 2007.  DNS & BIND, DDNS & DHCP.
-- 
David W. Hankins	"If you don't do it right the first time,
Software Engineer		you'll just have to do it again."
Internet Systems Consortium, Inc.	-- Jack T. Hankins