How does Deployment differ from StatefulSet?

Deployment and StatefulSet are controllers in Kubernetes that manage the creation and updating of pods, but they are designed for different scenarios.

Deployment is used for managing stateless applications, where pods do not depend on preserving state. It provides:

• Scaling
• Rolling updates with rollback
• Automatic pod recovery

Supports arbitrary order of pod creation and deletion.

StatefulSet is intended for stateful applications, where preserving state and the uniqueness of each pod are important. Differences include:

• Each pod receives a stable, unique identifier (name)
• Support for ordered deployment, scaling, and deletion
• Ability to bind to persistent volumes with data preservation

An example of using StatefulSet is databases, cache systems, where data integrity and the uniqueness of instances are crucial.

Thus, Deployment is chosen for stateless services, and StatefulSet for applications with state and requirements for order and stability of identifiers.