What does etcd store in a Kubernetes cluster?

Correct answer: All cluster state and configuration data

Option B is correct because etcd is the distributed key-value store that serves as Kubernetes' persistent backing store for all cluster state, including node information, Pod specs, ConfigMaps, Secrets, Service definitions, and controller state. Option A, node resource metrics, are collected by the metrics-server and stored in memory, not in etcd. Option C is incorrect because etcd stores far more than just network information; network configuration is one small part of the overall cluster state held in etcd. Option D is incorrect because container images are stored in container registries and logs are typically stored in node-level log files or external logging systems, not in etcd.