Book Image

Learning DevOps

By : Mikael Krief
Book Image

Learning DevOps

By: Mikael Krief

Overview of this book

The implementation of DevOps processes requires the efficient use of various tools, and the choice of these tools is crucial for the sustainability of projects and collaboration between development (Dev) and operations (Ops). This book presents the different patterns and tools that you can use to provision and configure an infrastructure in the cloud. You'll begin by understanding DevOps culture, the application of DevOps in cloud infrastructure, provisioning with Terraform, configuration with Ansible, and image building with Packer. You'll then be taken through source code versioning with Git and the construction of a DevOps CI/CD pipeline using Jenkins, GitLab CI, and Azure Pipelines. This DevOps handbook will also guide you in containerizing and deploying your applications with Docker and Kubernetes. You'll learn how to reduce deployment downtime with blue-green deployment and the feature flags technique, and study DevOps practices for open source projects. Finally, you'll grasp some best practices for reducing the overall application lead time to ensure faster time to market. By the end of this book, you'll have built a solid foundation in DevOps, and developed the skills necessary to enhance a traditional software delivery process using modern software delivery tools and techniques
Table of Contents (23 chapters)
Free Chapter
1
Section 1: DevOps and Infrastructure as Code
6
Section 2: DevOps CI/CD Pipeline
9
Section 3: Containerized Applications with Docker and Kubernetes
12
Section 4: Testing Your Application
16
Section 5: Taking DevOps Further

Introducing feature flags

Feature flags (also called feature toggle) allow us to dynamically enable or disable a feature of an application without having to redeploy it.

Unlike the blue-green deployment with the canary release pattern, which is an architectural concept, feature flags are implemented in the application's code.

Their implementation is done with a simple encapsulation using conditional if rules, as shown in the following code example:

if(activateFeature("addTaxToOrder")==True) {
ordervalue = ordervalue + tax
}else{
ordervalue = ordervalue
}

In this example code, the activateFeature function allows us to find out whether the application should add the tax to order according to the addTaxToOrder parameter, which is specified outside the application (such as in a database or configuration file).

Features encapsulated in feature flags may be necessary...