Frustrated DHCP failover not working.. :(

Niall O'Reilly niall.oreilly at
Wed Feb 10 17:27:11 UTC 2016

On 10 Feb 2016, at 16:36, Rob Morin wrote:

> Currently dhcp-1 daemon is not running, dhcp-2 is running and giving 
> out leases just fine, but in "stand alone" mode, meaning failover is 
> not configured.

   At least that's good!

> What i need to do is re-config dhcp-2 to be the secondary in a 
> failover mode,

   How important is it that dhcp-2 be the secondary, and not the 
   [Pas besoin de me répondre: c'est un point de réflexion]

> which would be just commentating the line in the dhcpd.conf file that 
> tells it that ir is the secondary, and then add dhcp-1 to the mix.

   It might be simpler to introduce dhcp-1 as secondary.

   If it's not acceptable to keep the servers in this "reversed" 
   I'ld suggest the sequence outlines below.  It's tedious, but avoids 
the solo/secondary
   transition which (a) scares me and (b) seems to be giving you 

   I've done this kind of juggling, but long enough ago that I don't 
remember enough
   detail to give you a tested worked example.  Besides, I don't work 
there any more
   and so no longer have access to the boxes.

   Initial condition: dhcp-2 in "solo" (less typing than "stand alone"!) 
   Ensure dhcp-1 is running the same version of the server code as 
   Prepare dhcp-2 to be primary and dhcp-1 to be secondary
   Enable failover and wait until stable operating conditions are 
   Note: this failover phase is simply a preparation for migrating to 
"solo" mode on dhcp-1
   Disable dhcp-2 and set dhcp-1 in "partner-down" mode
   Prepare dhcp-1 for "solo" operation and then restart it

   You should at this stage have the same situation as now, but with 
dhcp-1 in "solo" mode.

   Finally, prepare the target failover configuration (with dhcp-1 as 
primary) on each node
   and activate when ready.

   I'm not entirely sure that it will, but I hope this helps.

   Best regards,
   Niall O'Reilly

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