Fundamental K8s Terms, Part 00: Pod, Node, Cluster

Learning Kubernetes involves learning a whole set of new terms. Among the most essential are pod, node and cluster.

The official Kubernetes documentation has a Standardized Glossary with several dozens of of k8s terms. The Standardized Glossary is filterable. Filtering to show only Fundamental terms leaves you with just under 60 terms:

In the Fundamental K8s Terms series, we will select a few terms at a time to learn. Reading these blog posts will introduce these terms in the order in which I learned them. This is merely a suggested order based on my needs. I am documenting my experience in case you find it helpful! Some of the Fundamental terms are not unique to Kubernetes. Here are the Fundamental terms that I will not be covering in the Fundamental K8s Terms series:

I have linked to suggested articles in case you need to brush up on some of these terms. I would strongly encourage you to make sure you are comfortable with each of the four terms above before proceeding.

Fundamental K8s Terms

The terms we will cover in the first installment of this series are:

Chances are that one or more of these terms is familiar to you already. Let’s understand what these terms mean in a Kubernetes-context.

cluster

A cluster is a set of nodes. Each cluster has at least one node.

When you deploy Kubernetes, you get a cluster.

source

node

A node is a worker machine in Kubernetes. Pods run on a node. A node can be virtual machine or a physical machine.

pod

A pod is a set of tightly-coupled containers. A pod is a group of one or more containers with shared storage and network resources. All containers in a pod are co-located (on the same node).

Kubernetes by example: pods

A Kubernetes cluster consists of a set of worker machines; each worker machine is called a node. Each node hosts one or more pods.