There are two networking features or services that you get for free with your Docker swarm networks. The first is Service Discovery, and the second is load balancing. When you create Docker services, you get these features automatically. We experienced these features in this chapter and in Chapter 5, Docker Swarm, but didn't really refer to them by name. So, let's call them out here.
First up is Service Discovery. When you create a service, it gets a unique name. That name gets registered with the swarm DNS. And, every service uses the swarm DNS for name resolution. Here is an example for you. We are going to leverage the specifics-over overlay network we created earlier in the creating Docker networks section. We'll create two services (tester1 and tester2) attached to that network, then we will connect to a container in the tester1 services...