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

Template values

In previous chapters, we described values as parameters that are used to configure a Helm chart. Now, we will gain an understanding of how values are integrated into chart templates to dynamically generate Kubernetes resources.

Here is a basic ConfigMap template from the Git repository at chapter6/examples/values-example/templates/configmap.yaml:

apiVersion: v1
kind: ConfigMap
  name: values-example
data: |-
    chapterNumber={{ .Values.chapterNumber }}
    chapterName={{ .Values.chapterName }}

The last two lines of this template contain {{ .Values.chapterNumber }} and {{ .Values.chapterName }} actions, which are used as placeholders for the chapterNumber and chapterName values. This allows the ConfigMap to be parameterized based on the default chart values and the values the user provides during installation or upgrade.

Let’s take a look at the default chart...