Book Image

Learn Docker - Fundamentals of Docker 18.x

By : Dr. Gabriel N. Schenker
Book Image

Learn Docker - Fundamentals of Docker 18.x

By: Dr. Gabriel N. Schenker

Overview of this book

Docker containers have revolutionized the software supply chain in small and big enterprises. Never before has a new technology so rapidly penetrated the top 500 enterprises worldwide. Companies that embrace containers and containerize their traditional mission-critical applications have reported savings of at least 50% in total maintenance cost and a reduction of 90% (or more) of the time required to deploy new versions of those applications. Furthermore they are benefitting from increased security just by using containers as opposed to running applications outside containers. This book starts from scratch, introducing you to Docker fundamentals and setting up an environment to work with it. Then we delve into concepts such as Docker containers, Docker images, Docker Compose, and so on. We will also cover the concepts of deployment, orchestration, networking, and security. Furthermore, we explain Docker functionalities on public clouds such as AWS. By the end of this book, you will have hands-on experience working with Docker containers and orchestrators such as SwarmKit and Kubernetes.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Context-based routing


Often, we want to configure context-based routing for our Kubernetes cluster. Kubernetes offers us various ways to do so. The preferred and most scalable way at this time is to use an IngressController for this job. The following diagram tries to illustrate how this ingress controller works:

 Context-based routing using a Kubernetes ingress controller

In this diagram, we can see how context-based (or layer 7) routing works when using an ingress controller, such as Nginx. Here, we have a deployment of an application service called web. All the pods of this application service have a label app=web. We then have a Kubernetes service called web that provides a stable endpoint to those pods. The service has a (virtual) IP of 52.14.0.13 and exposes port 30044. That is, if a request comes to any node of the Kubernetes cluster for the name web and port 30044, then it is forwarded to this service. The service then load balances the request to one of the pods. 

So far so good, but...