Book Image

Continuous Delivery with Docker and Jenkins - Second Edition

By : Rafał Leszko
Book Image

Continuous Delivery with Docker and Jenkins - Second Edition

By: Rafał Leszko

Overview of this book

Continuous Delivery with Docker and Jenkins, Second Edition will explain the advantages of combining Jenkins and Docker to improve the continuous integration and delivery process of an app development. It will start with setting up a Docker server and configuring Jenkins on it. It will then provide steps to build applications on Docker files and integrate them with Jenkins using continuous delivery processes such as continuous integration, automated acceptance testing, and configuration management. Moving on, you will learn how to ensure quick application deployment with Docker containers along with scaling Jenkins using Kubernetes. Next, you will get to know how to deploy applications using Docker images and testing them with Jenkins. Towards the end, the book will touch base with missing parts of the CD pipeline, which are the environments and infrastructure, application versioning, and nonfunctional testing. By the end of the book, you will be enhancing the DevOps workflow by integrating the functionalities of Docker and Jenkins.
Table of Contents (18 chapters)
Title Page
Dedication
About Packt
Contributors
Preface
Index

Working with legacy systems


All we have described so far applies to greenfield projects, for which setting up a Continuous Delivery pipeline is relatively simple.

Legacy systems are, however, way more challenging, because they usually depend on manual tests and manual deployment steps. In this section, we will walk through the recommended scenario to incrementally apply Continuous Delivery to a legacy system.

As step zero, I recommend reading an excellent book by Michael Feathers, Working Effectively with Legacy Code. His ideas on how to deal with testing, refactoring, and adding new features address most of the concerns about how to automate the delivery process for legacy systems.

Note

For many developers, it may be tempting to completely rewrite a legacy system, rather than refactor it. While the idea is interesting from a developer's perspective, it is usually a bad business decision that results in a product failure. You can read more about the history of rewriting the Netscape browser...