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

Scheduling application replicas to different nodes (pod affinity)

Using nodeAffinity does not ensure that pods will next time be scheduled onto separate nodes, and for real application high availability, the best practice is to ensure that application pods are scheduled onto separate nodes. If one of the nodes is down/rebooted/replaced, having all the pods running on that node will cause the application to go down and its services to be unavailable.

Let's update the deployment.yaml file with the podAntiAffinity rule so that the nginx application is only scheduled to gke-kubectl-lab-we-app-pool and onto separate nodes:

        - matchExpressions:
          - key: node...