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)
1
Section 1: Getting Started with kubectl
3
Section 2: Kubernetes Cluster and Node Management
6
Section 3: Application Management
10
Section 4: Extending kubectl

Scaling up an application

In the previous section, we deployed an application with one replica; let's scale its deployment to two replicas.

The use case of running multiple replicas is to enable high availability for an application. To scale our deployment, run the following commands:

$ kubectl scale deployment nginx –replicas=2
deployment.apps/nginx scaled
$ kubectl get deployment nginx
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   2/2     2            2           5d17h
$ kubectl get pods
NAME                    READY   STATUS    RESTARTS   AGE
nginx-7df9c6ff5-chnrk   1/1 ...