Book Image

Learn Helm

By : Andrew Block, Austin Dewey
Book Image

Learn Helm

By: Andrew Block, Austin Dewey

Overview of this book

Containerization is currently known to be one of the best ways to implement DevOps. While Docker introduced containers and changed the DevOps era, Google developed an extensive container orchestration system, Kubernetes, which is now considered the frontrunner in container orchestration. With the help of this book, you’ll explore the efficiency of managing applications running on Kubernetes using Helm. Starting with a short introduction to Helm and how it can benefit the entire container environment, you’ll then delve into the architectural aspects, in addition to learning about Helm charts and its use cases. You’ll understand how to write Helm charts in order to automate application deployment on Kubernetes. Focused on providing enterprise-ready patterns relating to Helm and automation, the book covers best practices for application development, delivery, and lifecycle management with Helm. By the end of this Kubernetes book, you will have learned how to leverage Helm to develop an enterprise pattern for application delivery.
Table of Contents (15 chapters)
Section 1: Introduction and Setup
Section 2: Helm Chart Development
Section 3: Adanced Deployment Patterns
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Uninstalling the WordPress release

Uninstalling a Helm release means deleting the Kubernetes resources that it manages. In addition, the uninstall command deletes the release's history. While this is often what we want, specifying the --keep-history flag will instruct Helm to retain the release history.

The syntax for the uninstall command is very simple:

helm uninstall RELEASE_NAME [...] [flags]

Uninstall the WordPress release by running the helm uninstall command:

$ helm uninstall wordpress -n chapter3

Once uninstalled, you will see the following message:

release 'wordpress' uninstalled

You will also notice that the wordpress release no longer exists in the chapter3 namespace:

$ helm list -n chapter3

The output will be an empty table. You can also confirm that the release is no longer present by attempting to use kubectl to get the WordPress deployments:

$ kubectl get deployments -l app=wordpress -n chapter3
No resources found in chapter3...