Fallback & High Availability with nextdns-cli
I'm planning to install nextdns-cli on my 2 RPis and to use them in High Availability using keepalived (router DNS set to keepalived IP).
I'm using currently AdGuardHome, configured with more resolvers (ie OpenDNS & Cloudflare).
What will happen to my HA nextdns-cli installations, if NextDNS goes down? The network served by the 2 HA RPis will be down.
Is there a way to set a fallback (on nextdns-cli) to another DoH provider in case NextDNS is not able to reply to queries?
For example, my FritzBox is able to fallback to standard DNS if the DoT host is unreachable.