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 a cluster


All these techniques are great for scaling the application, but what about the cluster itself? At some point, you will pack the nodes full and need more resources to schedule new pods for your workloads.

Autoscaling

When you create your cluster, you can customize the starting number of nodes (minions) with the NUM_MINIONS environment variable. By default, it is set to 4.

Additionally, the Kubernetes team has started to build autoscaling capability into the cluster itself. Currently, this is only supported on GCE and GKE, but work is being done on other providers. This capability utilizes the KUBE_AUTOSCALER_MIN_NODES, KUBE_AUTOSCALER_MAX_NODES, and KUBE_ENABLE_CLUSTER_AUTOSCALER environment variables.

 

 

The following example shows how to set the environment variables for autoscaling before running kube-up.sh:

$ export NUM_MINIONS=5
$ export KUBE_AUTOSCALER_MIN_NODES=2
$ export KUBE_AUTOSCALER_MAX_NODES=5
$ export KUBE_ENABLE_CLUSTER_AUTOSCALER=true

Also, bear in mind that changing...