Foundational

If you want to learn how to get started managing and operating a Kubernetes cluster, this page and the linked topics introduce you to the foundational concepts and tasks. This page introduces you to a Kubernetes cluster and key concepts to understand and manage it. The content focuses primarily on the cluster itself rather than the software running within the cluster.

If you have not already done so, start your understanding by reading through What is Kubernetes?, which introduces a number of basic concepts and terms.

Kubernetes is quite flexible, and a cluster can be run in a wide variety of places. You can interact with Kubernetes entirely on your own laptop or local development machine with it running within a virtual machine. Kubernetes can also run on virtual machines hosted either locally or in a cloud provider, and you can run a Kubernetes cluster on bare metal.

A cluster is made up of one or more Nodes; where a node is a physical or virtual machine. If there is more than one node in your cluster then the nodes are connected with a cluster network. Regardless of how many nodes, all Kubernetes clusters generally have the same components, which are described in Kubernetes Components.

A good way to become familiar with how to manage and operate a Kubernetes cluster is by setting one up. One of the most compact ways to experiment with a cluster is Installing and using Minikube. Minikube is a command line tool for setting up and running a single-node cluster within a virtual machine on your local laptop or development computer. Minikube is even available through your browser at the Katacoda Kubernetes Playground. Katacoda provides a browser-based connection to a single-node cluster, using minikube behind the scenes, to support a number of tutorials to explore Kubernetes. You can also leverage the web-based Play with Kubernetes to the same ends - a temporary cluster to play with on the web.

You interact with Kubernetes either through a dashboard, an API, or using a command-line tool (such as kubectl) that interacts with the Kubernetes API. Be familiar with Organizing Cluster Access by using configuration files. The Kubernetes API exposes a number of resources that provide the building blocks and abstractions that are used to run software on Kubernetes. Learn more about these resources at Understanding Kubernetes Objects. These resources are covered in a number of articles within the Kubernetes documentation.

• Pod Overview
  • Pods
  • ReplicaSets
  • Deployments
  • Garbage Collection
  • Container Images
  • Container Environment Variables
• Labels and Selectors
• Namespaces
  • Namespaces Walkthrough
• Services
• Annotations
• ConfigMaps
• Secrets

As a cluster operator you may not need to use all these resources, although you should be familiar with them to understand how the cluster is being used. There are a number of additional resources that you should be aware of, some listed under Intermediate Resources. You should also be familiar with how to manage kubernetes resources and supported versions and version skew between cluster components.

You can access clusters using the Kubernetes API. If you are not already familiar with how to do this, you can review the introductory tutorial. Using kubectl, you can retrieve information about your Kubernetes cluster very quickly. To get basic information about the nodes in your cluster run the command kubectl get nodes. You can get more detailed information for the same nodes with the command kubectl describe nodes. You can see the status of the core of kubernetes with the command kubectl get componentstatuses.

Some additional resources for getting information about your cluster and how it is operating include:

• Tools for Monitoring Compute, Storage, and Network Resources
• Core metrics pipeline
  • Metrics

Tutorials

• Kubernetes Basics
• Configuring Redis with a ConfigMap
• Stateless Applications
  • Deploying PHP Guestbook with Redis
  • Expose an External IP address to access an application