# KUDO Kafka Concepts
KUDO Kafka is a Kubernetes operator built on top of KUDO and requires KUDO
# KUDO Kafka CRDs
There are three CRDs that are installed when deploying KUDO Kafka:
- Operator: the definition that describes the Kudo Kafka operator.
- OperatorVersion: the definition that describes the Kudo Kafka operator for a specific version.
- Instance: the instantiation of a KUDO Kafka cluster based on the OperatorVersion.
# KUDO Controller Reconcile Cycle
The KUDO controller continually watches the Operator, OperatorVersion and Instance CRDs via the Kubernetes API.
When a user installs KUDO Kafka using the
kudo-cli, the controller creates the KUDO Kafka CRDs for Operator, OperatorVersion and Instance. More information can be read in KUDO Architecture
When the KUDO Controller detects a new
Instance, it creates all the resources required to reach the desired state of the configuration.
The same process is followed for any updates or deletions. Everything is handled by the KUDO Controller.