Book Image

kubectl: Command-Line Kubernetes in a Nutshell

By : Rimantas Mocevicius
Book Image

kubectl: Command-Line Kubernetes in a Nutshell

By: Rimantas Mocevicius

Overview of this book

The kubectl command line tool lets you control Kubernetes clusters to manage nodes in the cluster and perform all types of Kubernetes operations. This introductory guide will get you up to speed with kubectl in no time. The book is divided into four parts, touching base on the installation and providing a general overview of kubectl in the first part. The second part introduces you to managing Kubernetes clusters and working with nodes. In the third part, you’ll be taken through the different ways in which you can manage Kubernetes applications, covering how to create, update, delete, view, and debug applications. The last part of the book focuses on various Kubernetes plugins and commands. You’ll get to grips with using Kustomize and discover Helm, a Kubernetes package manager. In addition to this, you’ll explore how you can use equivalent Docker commands in kubectl. By the end of this book, you’ll have learned how to install and update an application on Kubernetes, view its logs, and inspect clusters effectively.
Table of Contents (16 chapters)
Section 1: Getting Started with kubectl
Section 2: Kubernetes Cluster and Node Management
Section 3: Application Management
Section 4: Extending kubectl

Displaying node resource usage

It is handy to know what resources are consumed by nodes. To display the resources used by nodes, run the following command:

$ kubectl top nodes

We get the following list of nodes using the preceding command:

Figure 3.6 – Top nodes list with resources used

The previous command shows node metrics such as CPU cores, memory (in bytes), and CPU and memory percentage usage.

Also, by using $ watch kubectl top nodes, you can watch and monitor nodes in real time when, for example, load testing your application or doing other node operations.


The watch command might not be present in your computer, you might need to install it. The watch command will run the specified command and refresh the screen every few seconds.