[dnsdist] Dnsdist as high availability mode

[Frank Louwers]

Hi Affan,

As dns is mostly stateless, you can certainly use things like VRRP, CARP or other protocols for an HA setup. Theirs is no dnsdist specific documentation on this because there's nothing "special" about dnsdist that VRRP/CARP needs to know. You could use any documentation for your VRRP / CARP / other protocol out there.

That being said, I have two big remarks to make.

A lot of people who have a need to achieve this failover capability, prefer to do it BGP based, as you have a bit more control and predictability over the BGP protocol than for instance with VRRP(e). If you would launch a search query for "bgp dnsdist" or "bgp dns", you'll find a ton of blogposts and howtos. Again here: these blogposts talk about the BGP implementation, not soo much about dnsdist.

My second big remark is that dns has high-availability mechanisms built in: most TLDs require a minimum of 2 nameservers to be specified for authoritative name servers, all decent DNS client implementations allow you to specify more than one resolver. If you do this correctly, you'll achieve dns high-availability out of the box. Yes, there might be latency issues and you might get a higher rate of complaints from your users, but if those hiccups are short, the DNS protocol itself will fail over.

Kind Regards,

Frank


Frank Louwers
PowerDNS Certified Consultant @ Kiwazo.be

> On 10 Sep 2023, at 16:31, Affan Basalamah via dnsdist <dnsdist at mailman.powerdns.com> wrote:
> 
> Hello,
> 
> I want to know if it’s  possible to setup  dnsdist as two server and configured with first hop redundancy protocol such as VRRP (Keepalived on Linux, CARP on FreeBSD), so dnsdist can operate as highly available as possible, at least in fail over mode. 
> 
> If it’s possible, I haven’t seen the examples on the official dnsdist documentation. Can someone point me to any document or other references?
> 
> 
> Best regards,
> Affan 
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