Understanding the Guestbook operator control loop

In this chapter, we will write a Helm-based operator that will be used to install the Guestbook Helm chart. This chart can be found in the Packt repository at https://github.com/PacktPublishing/Managing-Kubernetes-Resources-using-Helm/tree/main/helm-charts/charts/guestbook.

The following diagram demonstrates how the Guestbook operator will function once it has been deployed:

Figure 11.1 – The Guestbook operator control loop

The Guestbook operator constantly watches for the creation, deletion, or modification of Guestbook CRs. When a Guestbook CR is created, the operator will install the Guestbook Helm chart, and when the CR is modified, it upgrades the release accordingly so that the state of the cluster matches the desired intent as defined by the CR. Similarly, when the CR is deleted, the operator uninstalls the release.

With an understanding of how the operator’s control loop will...