You have just learned about all of the incredible features that get enabled and set up when you create a Docker swarm cluster. So, now I am going to show you all of the steps needed to set up a Docker swarm cluster. Are you ready? Here they are:

# Set up your Docker swarm cluster
docker swarm init

What? Wait? Where is the rest of it? Nope. There is nothing missing. All of the setup and functionality that is described in the preceding section is achieved with one simple command. With that single swarm init command, the swarm cluster is created, the node is transformed from a single-instance node into a swarm-mode node, the role of manager is assigned to the node and it is elected as the leader of the swarm, the cluster store is created, the node becomes the certificate authority of the cluster and assigns itself a new certificate that includes a cryptographic ID, a new cryptographic join token is created for managers, and another is created for workers, and on and on. This is complexity made simple.

The swarm commands make up another Docker management group. Here are the swarm-management commands:

We'll review the purpose for each these commands in just a moment, but before we do, I want to make you aware of some important networking configurations. We will talk more about Docker networking in Chapter 6, Docker Networking, but for now be aware that you may need to open access to some protocols and ports on your Docker nodes to allow Docker swarm to function properly. Here is the information straight from Docker's Getting started with swarm mode wiki:

Two other ports that you may need to open for the REST API are as follows:

• TCP 2375 for Docker REST API (plain text)
• TCP 2376 for Docker REST API (ssl)

Alright, let's move on to reviewing the swarm commands.