[Dnsmasq-discuss] Documented Redundancy?

[Simon Kelley]

On 30/07/14 07:35, Joel Krauska wrote:
> I've seen a few interesting proposals for running dnsmasq in a redundant
> way.
> (running active/passive and trying to keep leases updated atomically, eg.
> using a db)
> 
> But I haven't seen an actual implementation documented anywhere.
> 
> Those concepts mostly 'address' setting up a standby dhcp server, but I'm
> also interested in a secondary DNS server implementation using dnsmasq, and
> I can't seem to find detailed documentation on that either.
> 
> Just in case anyone is wondering 'why' -- machines need package updates and
> occasional rebooting.  I'd very much like to be able to temporarily take
> down my primary dhcp/dns infra with minimal impact.
> 
> I've used isc and bind, and frankly it's a PITA to manage and maintain.
> 
> I really like the simplicity of dnsmasq, but I'd also like some manageable
> redundancy?
> 
> Is there a blog post out there that I just can't seem to find?  :)
> 
> If not, I guess I'll have to try to make one myself.
> 
> Cheers,
> 
> Joel Krauska

I'm not aware of anybody having done this and documented it. The insight
that you don't really need redundancy for DHCP, only DNS is a valid one.
Maybe it would work to have a secondary dnsmasq configured only for DNS,
and make the primary maintain a file in /etc/hosts file format with the
DHCP hosts and their addresses. The DHCP script is provided with enough
information to maintain a complete lease database, so just the
names/addresses would be quite possible. Moving that file from master to
slave left as an exercise for the reader :)

Cheers,

Simon.