Centralized DNS server
I would suggest if HC can add this feature in any of the upcoming builds.
We should be able to setup a standalone DNS server with a secondary server for the secondary DNS and that standalone DNS server would be used as a centralized DNS server for all the hosting controller clusters. This will allow to have a common DNS servers for all the websites hosted via HC on separate HC clusters. To support this, HC can allow multiple master instances in HC slave which will be used in the DNS server. This way, it can be used for all the HC clusters.