New Feature: .flycast domains

Hello folks! New feature for you today: appname.flycast domains. They behave like appname.internal domains except they only return flycast addresses (if you have any) of the app.

The original motivation for this is accommodating postgres clients that don’t like raw ipv6 in the connection string.

The eagle eyed, and elephant memoried of you might remember that we introduced flycast for postgres to get away from DNS! Why are we going back? The problem we were trying to get away from with DNS is avoiding the case where there is a lag between a postgres instance becoming unhealthy or dying and it getting removed from DNS. Flycast ips don’t change so we don’t have to worry about that issue in this case.

Flyctl v0.0.474 onwards will use the .flycast domains by default for postgres. In the meantime users can manually replace the flycast ip or .internal address in the DATABASE_URL and set it in their app with fly secrets set DATABASE_URL=...


Do these flycast domains work for apps that have had private flycast IPv6s manually configured? Or is it only for postgres at the moment?

Works for any apps with flycast ips! Not just postgres ones.