What is Kubernetes?

Last updated on 2025-01-07 | Edit this page

Overview

Questions

  • What is Kubernetes and why might I want to use it?

Objectives

  • Understand what Kubernetes is and when you might want to utilize it.
  • Utilize Kubernetes commands to interact with a Kubernetes environment.

Kubernetes, or “k8s” is an open source container orchestration platform to automate deploying, scaling, and managing containers within an environment. Traditionally, Kubernetes is aimed towards commercial environments and cloud infrastrutuce. Originally developed by Google and realeased open source and is now managed by the Cloud Native Computing Foundation or CNCF.

Discuss with your neighbor

What are some challenges you may have when you move from one computational environment to another for your research? For example moving from a local compute cluster to a different compute cluster.

Some examples you may have discussed:

  • Different methods of interacting with the environment
  • Keywords could be different or processed differently
  • Software may not be available readily

Kubernetes provides a uniform platform and method across many different local and commericial cloud infrastructure. This ensures that your application is able to operate the same from your local developmment system to a production Kubernetes environment or a commercial cloud environment. This also helps ensure that a research workflow using Kubernetes is able to be reproduced on any infrastructure using Kubernetes.

Kubernetes deployments and environments are managed using YAML files. These YAML files allow you to tell the Kubernetes cluster what you want from a specific environment for the cluster then to attempt to make that defined configuration. This also increases the ability to change things in a recorded manner using version control tools like Git.

Make sure everything is ready

Before proceeding, double check that you have kubectl connected to a Kubernetes instance. kubectl get nodes will retreive all of the computers or nodes running in the Kubernetes environment.

BASH 

$ kubectl get nodes

You should see output similar to this:

OUTPUT 

NAME       STATUS   ROLES           AGE   VERSION
minikube   Ready    control-plane   90d   v1.30.0

Double check things are good to go

Lets also double check by looking at the available namespaces. We will talk more about what these are later.

BASH 

$ kubectl get namespaces

You should see output similar to this:

OUTPUT 

NAME                   STATUS   AGE
default                Active   90d
kube-node-lease        Active   90d

The kubectl command does not directly control the state of a Kubernetes cluster. Instead it communicates directly to the Kubernetes’ controller through an API server. When you run kubectl apply or kubectl delete, the command execution doesn’t directly change the environment. Instead it tells the controller through the API server an expected state of the environment and the Kubernetes controller will attempt to make the declared state the current state and keep the cluster in the desired state. This is called “declarative management”, which simplifies the management of more complex systems.

Talk about it

With docker or other container platforms, what challenges may come up as you start scaling up and running more workflows?

Some challenges you may have thought of:

  • Needing to micromanage everything running as projects scale
  • Many working components needing configured