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

Rolling back the WordPress release

While moving forward is preferred, there are some occasions where it makes more sense to return to a previous version of the application. The helm rollback command exists to satisfy this use case. Let’s describe how to roll back the WordPress release to a previous state.

Inspecting the WordPress history

Every Helm release has a history of revisions. A revision is used to track the values, Kubernetes resources, and the chart version that were used in a particular release version. A new revision is created when a chart is installed, upgraded, or rolled back. Revision data is saved in Kubernetes Secrets by default (other options are ConfigMaps, local memory, or a PostgreSQL database, as determined by the HELM_DRIVER environment variable). This allows your Helm release to be managed and interacted with by different users on the Kubernetes cluster, provided they have the appropriate Role-Based Access Control (RBAC) permissions to view or modify...