github.com/rafaeljusto/dnsdisco (go): Package dnsdisco is a DNS service discovery library with health check and load balancer features.  The library is very flexible and uses interfaces everywhere to make it possible for the library user to replace any part with a custom algorithm. Check the examples for more details.  Example_loadBalancer shows how it is possible to replace the default load balancer algorithm with a new one following the round robin strategy (https://en.wikipedia.org/wiki/Round-robin_scheduling).
Keywords: dns|health-check|load-balancer|service-discovery