In Kubernetes architecture, which component is considered the "source of truth" for all cluster state and configuration?

• A. API Server
• B. Scheduler
• C. kubelet
• D. etcd

Answer: (D)

etcd is the distributed key-value store that persists the entire cluster state and configuration. It is the authoritative data store, so it serves as the source of truth for Kubernetes. The API Server acts as the front door to this data, enforcing schema and access control, while the scheduler and kubelet interact with the API Server to read and update state but do not own the canonical cluster state themselves. Because etcd stores all objects and settings, safeguarding and backing up etcd is essential.