[CentOS] how to increase DNS reliability?

Thu Jul 25 21:34:41 UTC 2019
Giles Coochey <giles at coochey.net>

On 25/07/2019 22:17, Giles Coochey wrote:
> Separate DNS servers must be on a different subnet according to 
> RFC2182 (https://tools.ietf.org/html/rfc2182):
> Secondary servers must be placed at both topologically and
>    geographically dispersed locations on the Internet, to minimise the
>    likelihood of a single failure disabling all of them.
> I know that UPSs are physical, and subnets are logical, but the 
> reasoning behind the requirement is due to having to be on a different 
> infrastructure.
> __

Shock horror, replying to my own post, but in cloud cluster 
environments, you might consider anti-affinity rules to prevent multiple 
name servers going down at the same time due to a cluster node failure 
(i.e. rules to ensure that hypervisors keep different name servers on 
different hosts).

I know it doesn't help OP, who was looking for cluster based solutions, 
but the same applies if using load balancing virtual appliances, hosting 
IPs as name servers.