DHCP Failover -- Proper method for adding pools to an existing setup.

Glenn Satchell Glenn.Satchell at uniq.com.au
Thu Aug 30 13:43:35 UTC 2007

All looks reasonable except for step 7, although I think you are
over-complicating things.

The way I normally do it:

1. edit dhcpd.conf
2. syntax check
3. copy to secondary (I have an include file that handles the failover peer 
4. restart dhcpd on secondary
5. restart dhcpd on primary


>Date: Wed, 29 Aug 2007 12:08:28 -0500
>From: "Cory Meyer" <cory.meyer at gmail.com>
>To: dhcp-users at isc.org
>Subject: DHCP Failover -- Proper method for adding pools to an existing setup.
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>Does anyone have any methods or examples of the proper way to add additional
>pools to a currently running  failover setup?
>In my test setup I have 2 Debian Sarge servers both running 3.0.5.
>The current method that I'm testing is:
>1.  Update dhcp configuration with the new pool info.
>2.  Test ( /usr/sbin/dhcpd -t -cf /etc/dhcp/dhcpd.conf )
>  * Continue if configuration passed.
>3.  Via OMAPI put the secondary dhcp server into shutdown mode
>4.  Kill dhcpd process since the shutdown mode didn't actually kill the
>5.  Restart dhcpd on the primary server,   primary moves from startup to
>6.  copy pools configuration from primary to secondary.
>7.  Clean out leases on secondary (cat /dev/null > /var/state/dhcpd.leases)
>   * Above is required to remove the shutdown state.
>8.  Start dhcpd process on secondary.
>9.  Secondary moves from startup to recover.

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