Help with DHCP failover configuration

[Chris Buxton]

On Aug 8, 2011, at 8:02 AM, Phusion wrote:

> I am in need of some assistance with DHCP failover. First of all both
> of the servers are running 3.1-ESV. I've tried configured the servers
> to run in a cooperating partner relationship to try and provide both
> redundancy and load-balancing. As a test, I stopped the DHCP service
> on the secondary server and eventually started to get messages like
> this one on the primary server.
> 
> Aug  8 07:06:59 dhcp01 dhcpd: DHCPDISCOVER from xx:xx:xx:xx:xx:xx
> (workstation) via fxp0: peer holds all free leases

This is normal. Put the remaining server into partner-down state, rather than communications-interrupted (which is what you get by default when one server goes down). Otherwise, once you hit the 50% full mark, you might start to see this.

You should always monitor your DHCP servers to detect when one partner goes down. Usually an SNMP implementation is sufficient, but a log server is also helpful. The log server could be configured to send an alert when either server logs a state change.

Chris Buxton
BlueCat Networks