Immutable Infrastructure and Continuous Delivery in the Cloud

by Paul Bourdel

Introduction

There are many benefits of immutable infrastructure as well as continuous delivery. The goal of this blog post is to lightly go over those benefits as well as provide an example on how to achieve both on a cloud provider.

Immutable Infrastructure

Immutable infrastructure is similar to an immutable object in functional programming. Once it is created it is never modified. In this blog post we’re specifically talking about the application server. The creation of the application server is fully automated as part of the build process. The scripts used for the creation of the application server are stored in the source repository of the project alongside the application source code. Once the application server is built it is never modified by hand. If a change is needed to the server’s configuration, the change is made to the server setup scripts and a new server is built after the changes are committed. The changes will then go live during the next deployment.

Packer

Packer is a tool for creating virtual machine images on different cloud platforms such as Rackspace or Amazon Web Services. It is launched from the command line and configured with a JSON formatted…