In this post, I will explain how to create a highly available, self-routing sharded Varnish Cache cluster. This is similar to a standard sharded cluster with one exception, there is no dedicated routing tier. Each node in the cluster can route the request to the proper destination node, by itself.
Varnish High Availability (VHA) is a high-performance content replicator for Varnish Plus. Using VHA with a group of Varnish Plus servers ensures that the cached objects will be efficiently replicated between caches when first fetched from the backend. This both provides higher performance to the client, and minimizes backend traffic.