Using Helm with the Operator Framework

One of the advantages of using Helm is the ability to declaratively define an application’s desired state. With Helm, the desired state is managed with templates and Helm values, which, when provided using the install or upgrade commands, apply the values to synchronize the live state in a Kubernetes cluster. In previous chapters, this was performed by invoking those commands manually. Most recently, in Chapter 10, Automating Helm with CD and GitOps, we used Argo CD as a method of state synchronization.

Another way changes can be synchronized to a Kubernetes cluster is to use a controller that checks periodically that the desired state matches the current configuration in the environment. If the state does not match, the application can automatically modify the environment to match the desired state. This controller is the foundation of applications and is referred to as a Kubernetes operator.

In this chapter, we will create a Helm...