Preface

The emergence of Kubernetes as a standard platform for distributed computing has revolutionized the landscape of enterprise application development. Organizations and developers can now easily write and deploy applications with a cloud-native approach, scaling those deployments to meet the needs of them and their users. However, with that scale comes increasing complexity and a maintenance burden. In addition, the nature of distributed workloads exposes applications to increased potential points of failure, which can be costly and time-consuming to repair. While Kubernetes is a powerful platform on its own, it is not without its own challenges.

The Operator Framework has been developed specifically to address these pain points by defining a standard process for automating operational tasks in Kubernetes clusters. Kubernetes administrators and developers now have a set of APIs, libraries, management applications, and command-line tools to rapidly create controllers that automatically create and manage their applications (and even core cluster components). These controllers, called Operators, react to the naturally fluctuating state of a Kubernetes cluster to reconcile any deviation from the desired administrative stasis.

This book is an introduction to the Operator Framework for anyone who is interested in, but unfamiliar with, Operators and how they benefit Kubernetes users, with the goal of providing a practical lesson in designing, building, and using Operators. To that end, it is more than just a technical tutorial for writing Operator code (though it does walk through writing a sample Operator in Go). It is also a guide on intangible design considerations and maintenance workflows, offering a holistic approach to Operator use cases and development to guide you toward building and maintaining your own Operators.