[Dnsmasq-discuss] How do others provide backup for their DNS? Ideas wanted

Chris Green cl at isbd.net
Thu Sep 2 08:05:28 UTC 2021


On Wed, Sep 01, 2021 at 01:04:24PM -0700, Michael wrote:
> On 9/1/21 11:45 AM, Chris Green wrote:
> > Thanks for the replies.
> > 
> > It does seem that any sort of live failover for DHCP and/or DNS turns
> > out to be quite complex.
> > 
> > I am thus thinking that simply having a reasonably quick to start
> > 'cold' backup makes sense.  I really don't mind if my LAN is DNS and
> > DHCP'less for an hour or so, it can cope!
> > 
> > The best idea (and I haven't really thought about the practicalities
> > yet) I have had so far is a dual boot Raspberry Pi or similar that
> > reboots itself to the 'other' OS in the small hours, backs up the
> > 'main' OS (which is the dnsmasq server) and then reboots back to the
> > 'main' server.  One then has a daily cloned image of the dnsmasq
> > server which can be plugged into backup hardware if the server fails.
> > 
> > 
> 
> Hi Chris,
> 
> 
> This is a topic that has come up periodically over the years and I too have
> watched with interest on how to best manage this.
> 
> 
> I looked at using heartbeat and other failover service to handle any
> potential failure. but it just becomes so complicated if you are using DHCP
> too.   If you do just DNS, then this is all much simpler.
> 
> 
> Here is what I am doing now:
> 
> 1) Run dnsmasq (pihole actually) in a docker container on my
> "infrastructure" server.   It has a static IP/MAC separate from the
> infrastructure server.
> 
> 2) Hourly, I rsync the docker data directory for pihole over to my desktop
> machine.   This contains the /etc/pihole directory, leases file, /etc/hosts
> file, etc.  It is a super tiny amount of data
> 
> 3) On my desktop, I have docker installed and ready to go including the
> pihole install.
> 
> 
> Then, when I have a failure or want to do maintenance, I just stop the
> pihole docker on the infrastructure server and start the pihole container on
> the desktop.   The service comes up with the same IP and MAC and the clients
> never know it happened.    When I am done, I just reverse the process.
> 
> 
> It seems to work fine for my needs.
> 
That sounds a good practical approach and would work for me I think.

I think I need to learn about docker.  Is there a beginners guide
anywhere that explains how to do something simple like I would want to
do?

The only other issue is that the only 'servers' I have on my system
(apart from my desktop machine) are Pis, however I see no reason for
not using one of them.

-- 
Chris Green



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