This is a fairly important topic in the world of containers, when we start to move into multinode applications and Docker schedulers. The question is what is service discovery? Is it limited to containers? What are the types of service discovery for us to make smart design choices in our Puppet modules.
Service discovery is essential when we start to work with multinode applications, as it allows our applications to talk to each other as they move from node to node. So, as you can see in the world of containers, this is fairly important. We have a few choices when we choose a service discovery backend. The two big names in this space are etcd (https://coreos.com/etcd/), which again is from CoreOS, and Consul from HashiCorp (https://www.consul.io/).
You might remember that we have already written a consul module. So for this chapter, we are going to choose the same, as we already have the written code. First, let's look at the architecture of Consul so we can understand...