etcd
etcd is a distributed, consistent key-value store designed for reliable distributed coordination and configuration management in cloud-native systems. It provides a simple HTTP/JSON API for storing and retrieving data, with strong consistency guarantees using the Raft consensus algorithm. It is widely used as the backbone for service discovery, leader election, and distributed locking in container orchestration platforms like Kubernetes.
Developers should learn etcd when building or operating distributed systems that require reliable configuration storage, service discovery, or coordination mechanisms, especially in cloud-native environments. It is essential for Kubernetes administrators and developers working on microservices architectures, as it serves as Kubernetes' primary data store for cluster state, enabling features like pod scheduling and service endpoints.