Book Image

Getting Started with Kubernetes - Third Edition

By : Jonathan Baier, Jesse White
Book Image

Getting Started with Kubernetes - Third Edition

By: Jonathan Baier, Jesse White

Overview of this book

Kubernetes has continued to grow and achieve broad adoption across various industries, helping you to orchestrate and automate container deployments on a massive scale. Based on the recent release of Kubernetes 1.12, Getting Started with Kubernetes gives you a complete understanding of how to install a Kubernetes cluster. The book focuses on core Kubernetes constructs, such as pods, services, replica sets, replication controllers, and labels. You will understand cluster-level networking in Kubernetes, and learn to set up external access to applications running in the cluster. As you make your way through the book, you'll understand how to manage deployments and perform updates with minimal downtime. In addition to this, you will explore operational aspects of Kubernetes , such as monitoring and logging, later moving on to advanced concepts such as container security and cluster federation. You'll get to grips with integrating your build pipeline and deployments within a Kubernetes cluster, and be able to understand and interact with open source projects. In the concluding chapters, you'll orchestrate updates behind the scenes, avoid downtime on your cluster, and deal with underlying cloud provider instability within your cluster. By the end of this book, you'll have a complete understanding of the Kubernetes platform and will start deploying applications on it.
Table of Contents (23 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Scaling up


Over time, as you run your applications in the Kubernetes cluster, you will find that some applications need more resources, whereas others can manage with fewer resources. Instead of removing the entire ReplicationControllers (and associated pods), we want a more seamless way to scale our application up and down.

Thankfully, Kubernetes includes a scale command, which is suited specifically for this purpose. The scalecommand works both with ReplicationControllers and the new Deployments abstraction. For now, we will explore its use with ReplicationControllers. In our new example, we have only one replica running. You can check this with a get pods command:

$ kubectl get pods -l name=node-js-scale

 

 

Let's try scaling that up to three with the following command:

$ kubectl scale --replicas=3 rc/node-js-scale

If all goes well, you'll simply see the scaled word on the output of your Terminal window.

Note

Optionally, you can specify the --current-replicas flag as a verification step. The scaling...