I've been searching around, but cannot seem to find an answer so I apologize if this has been asked here before.
I had two PowerDNS servers -
ns2 (which are in different datacenters). Both connet to MySQL on localhost, but MySQL on both servers are replication slaves of the MySQL master
db. This works very well, as updating the dns database on
db will replicate to
ns2, and then powerdns will properly show the DNS records in both places.
What I am trying to accomplish, but cannot seem to figure out, is how to deal with a situatuion where the mysql host on either
ns2 crashes. If mysql fails, how can I tell powerdns to forward DNS queries to the other server temporarily (until mysql comes back online)? I have looked into pdns-recursor, but I can't seem to see how to configure it only to run when mysql is down.
I'm open to creative solutions, like using pdns on an abnormal port and then nginx to "proxy" the connection to another port on the server, and allowing nginx to be notified of the mysql failure and redirect to the other server. The problem being I wouldn't know where to start to set something like that up! I'm wondering (a) what is best practice / most reliable, and (b) how specifically do I do it!