Book Image

Mastering Kubernetes

By : Gigi Sayfan
Book Image

Mastering Kubernetes

By: Gigi Sayfan

Overview of this book

Kubernetes is an open source system to automate the deployment, scaling, and management of containerized applications. If you are running more than just a few containers or want automated management of your containers, you need Kubernetes. This book mainly focuses on the advanced management of Kubernetes clusters. It covers problems that arise when you start using container orchestration in production. We start by giving you an overview of the guiding principles in Kubernetes design and show you the best practises in the fields of security, high availability, and cluster federation. You will discover how to run complex stateful microservices on Kubernetes including advanced features as horizontal pod autoscaling, rolling updates, resource quotas, and persistent storage back ends. Using real-world use cases, we explain the options for network configuration and provides guidelines on how to set up, operate, and troubleshoot various Kubernetes networking plugins. Finally, we cover custom resource development and utilization in automation and maintenance workflows. By the end of this book, you’ll know everything you need to know to go from intermediate to advanced level.
Table of Contents (22 chapters)
Mastering Kubernetes
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Shared environment variables versus DNS records for discovery


Kubernetes provides several mechanisms for global discovery across the cluster. If your storage cluster is not managed by Kubernetes, you still need to tell Kubernetes pods how to find it and access it. There are two main methods:

  • DNS

  • Environment variables

In some cases, you may want to use both where environment variables can override DNS.

Accessing external data stores via DNS

The DNS approach is simple and straightforward. Assuming your external storage cluster is load balanced and can provide a stable endpoint, then pods can just hit directly that endpoint and connect to the external cluster.

Accessing external data stores via environment variables

Another simple approach is to use environment variables to pass connection information to an external storage cluster. Kubernetes offers the ConfigMap resource as a way to keep configuration separate from the container image. The configuration is a set of key-value pairs. The configuration...