AWS Service registry for resilient mid-tier load balancing and failover.
Zuul is a gateway service that provides dynamic routing, monitoring, resiliency, security, and more.
Ribbon is a Inter Process Communication (remote procedure calls) library with built in software load balancers. The primary usage model involves REST calls with various serialization scheme support.
Hystrix is a latency and fault tolerance library designed to isolate points of access to remote systems, services and 3rd party libraries, stop cascading failure and enable resilience in complex distributed systems where failure is inevitable.
(15) spinnaker: https://www.spinnaker.io/