The ultimate Kubernetes pocket knife. ytt-operator allows you to create simple, application specific operators using only YAML.
You provide a YAML config file consisting of one (or more) GroupVersionKind's and a path to a directory containing ytt templated YAML files. ytt-operator will then evaluate the ytt templates (passing the original object as a data value) and apply the resulting YAML's to the cluster. ytt-operator is particularly useful for creating abstractions on top of existing operators.
Sometimes wrestling with kubebuilder just isn't worth it.
Note: As ytt-operator does not know what resource kinds you will be watching or creating at build time, you will need to create a custom ClusterRole for your application (this has been omitted).
$ kubectl apply -k config/default