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

Introduction to Kustomize

Kustomize uses overlays for Kubernetes manifests to add, remove, or update configuration options without forking. What Kustomize does is take a Kubernetes template, patch it with specified changes in kustomization.yaml, and then deploy it to Kubernetes.

It is a handy tool for patching non-complex applications, for example, with changes needed for different environments or resource namespacing.

Kustomize is available as a standalone binary and as a native command in kubectl since v.1.14.

Let's look at a couple of Kustomize commands, use the following command:

  • To show the generated modified templates on the terminal, use the following command:
    $ kubectl kustomize base 
  • To deploy generated modified templates on Kubernetes:
    $ kubectl apply –k base

In the preceding examples, base is the folder that has the application files and kustomization.yaml.


The preceding commands will fail as there is no base folder. This...