The operator watches additions, updates, and deletions of PostgreSQL cluster manifests and changes the running clusters accordingly. For example, when a user submits a new manifest, the operator fetches that manifest and spawns a new Postgres cluster along with all necessary entities such as Kubernetes StatefulSets and Postgres roles. See this Postgres cluster manifest for settings that a manifest may contain. The operator also watches updates to its own configuration and alters running Postgres clusters if necessary. For instance, if a pod docker image is changed, the operator carries out the rolling update. That is, the operator re-spawns one-by-one pods of each StatefulSet it manages with the new Docker image.