DHCP failover not balancing
David W. Hankins
David_Hankins at isc.org
Thu Sep 4 22:57:44 UTC 2008
On Tue, Sep 02, 2008 at 12:44:53PM +0800, li jun wrote:
> and also the same problem troubles me for a long time
> would anyone help me
>
> > Primary server:
> > Aug 20 09:17:04 primary dhcpd: balancing pool 8123240 1.2.3/22 total
> > 949 free 206 backup 382 lts -88 max-own (+/-)59 Aug 20
> > 09:17:04 primary dhcpd: balanced pool 8123240 1.2.3/22 total
> > 949 free 206 backup 382 lts -88 max-misbal 88
> >
> > Secondary server:
> > Aug 20 09:17:04 secondary dhcpd: balanced pool 8123178 1.2.3/22 total
> > 949 free 588 backup 0 lts -294 max-misbal 88 Aug 20
> > 09:17:04 secondary dhcpd: balancing pool 814e9f0 1.2.3/22
> > total 30 free 19 backup 0 lts -9 max-own (+/-)2
> > (requesting peer rebalance!)
This sort of problem is a straight database inconsistency ("backup 0"
is the key). Additionally, I'm concerned that for 1.2.3/22, it seems
the primary and secondary are not consistently configured (the 'total'
count is way off).
To get your servers back up and running, you want to "fault" the lease
database; in this case the secondary's.
kill dhcpd
mv dhcpd.leases dhcpd.leases.save
touch dhcpd.leases
dhcpd [flags/options]
The servers should cycle through recovery and get back to operational.
I'm tracking a 3.0.x->3.1.x migration problem with lease database
consistency, we'll publish a fix in the next maintenance release, but
I'm not aware of any recurring/persistent problems here (yet?).
To fix the configuration inconsistency, the BCP on failover ops right
now is to run a dhcpd.conf on each server, and a dhcpd.include.conf
for the subnet/etc configs, then include it from the server-specific
dhcpd.conf's. Just scp the included dhcpd.conf between the servers
when you reconfigure. This way you are very well assured they are
both loading the same config.
--
Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
Why settle for the lesser evil? https://secure.isc.org/store/t-shirt/
--
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
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