Programming Kubernetes

Chapter 7. Shipping Controllers and Operators

Now that you’re familiar with the development of custom controllers, let’s move on to the topic of how to make your custom controllers and operators production-ready. In this chapter we’ll discuss the operational aspects of controllers and operators, showing you how to package them, walking you through best practices for running controllers in production, and making sure that your extension points don’t break your Kubernetes cluster, security, or performance-wise.

Lifecycle Management and Packaging

In this section we consider the lifecycle management of operators. That is, we will discuss how to package and ship your controller or operator, as well as how to handle upgrades. When you’re ready to ship your operator to users, you’ll need a way for them to install it. For this, you need to package the respective artifacts, such as YAML manifests that define the controller binary (typically as a Kubernetes deployment), along with the CRDs and security-related resources, such as service accounts and the necessary RBAC permissions. Once your targeted users have a certain version of the operator running, you will also want to have a mechanism in place for upgrading the controller, considering versioning and potentially zero-downtime upgrades.

Let’s start with the low-hanging fruit: packaging and delivering your controllers so that a user can install it in a straightforward manner.

Packaging: The Challenge

While Kubernetes defines resources ...