Book Image

Managing Kubernetes Resources Using Helm - Second Edition

By : Andrew Block, Austin Dewey
Book Image

Managing Kubernetes Resources Using Helm - Second Edition

By: Andrew Block, Austin Dewey

Overview of this book

Containerization is one of the best ways to implement DevOps, and learning how to execute it effectively is an essential part of a developer’s skillset. Kubernetes is the current industry standard for container orchestration. This book will help you discover the efficiency of managing applications running on Kubernetes with Helm. Starting with a brief introduction to Helm and its impact on users working with containers and Kubernetes, you’ll delve into the primitives of Helm charts and their architecture and use cases. From there, you’ll understand how to write Helm charts in order to automate application deployment on Kubernetes and work your way toward more advanced strategies. These enterprise-ready patterns are focused on concepts beyond the basics so that you can use Helm optimally, looking at topics related to automation, application development, delivery, lifecycle management, and security. By the end of this book, you’ll have learned how to leverage Helm to build, deploy, and manage applications on Kubernetes.
Table of Contents (18 chapters)
Part 1: Introduction and Setup
Part 2: Helm Chart Development
Part 3: Advanced Deployment Patterns

Declaring chart dependencies

Chart dependencies are used to install another chart’s resources that a Helm chart (referred to as the parent chart) may depend on. We saw an example of chart dependencies in action when we installed WordPress in Chapter 3, Installing Your First App with Helm. When we installed WordPress, we used the wordpress chart to install both the WordPress application instance and a MariaDB backend. You may be surprised to learn that the MariaDB database that was installed was not a native WordPress chart resource – it was a dependency! We can confirm this fact by running the helm show chart command to view the dependencies declared in the wordpress Chart.yaml file:

$ helm show chart bitnami/wordpress --version 12.1.4

In the output, you’ll see the dependencies map, as follows:

- condition: mariadb.enabled
  name: mariadb