Domain Name System Service Discovery. This resolves to the cluster IP of the Service. In computer networking the multicast DNS mDNS protocol resolves hostnames to IP addresses within small networks that do not include a local name serverIt is a zero-configuration service using essentially the same programming interfaces packet formats and operating semantics as the unicast Domain Name System DNS.
The DNS suffix of a client differs from its DNS domain name. Although Stuart Cheshire designed mDNS as a stand-alone protocol it can. Amazon ECS Reference Architecture.
With multiple service instances you need a load balancer and some way to quickly inform it of changes to the set of available service instances.
If you think the picture below looks a lot like the old Macintosh AppleTalk Chooser thats no coincidence. DNS Service Discovery DNS-SD DNS Service Discovery is a way of using standard DNS programming interfaces servers and packet formats to browse the network for services. Services AAAAA records Normal not headless Services are assigned a DNS A or AAAA record depending on the IP family of the service for a name of the form my-svcmy-namespacesvccluster-domainexample. The computer is a member of a group in a different domain such as Domain B.