Today, the Cloud Native Computing Foundation (CNCF) Technical Oversight Committee (TOC) voted to accept etcd as an incubation-level hosted project from KubeCon + CloudNativeCon Seattle. All Kubernetes clusters use etcd as their primary data store.
As such, it handles storing and replicating data for Kubernetes cluster state and uses the Raft consensus algorithm to recover from hardware failure and network partitions. In addition to Kubernetes, Cloud Foundry also uses etcd as their distributed key-value store. This means etcd is used in production by companies such as Ancestry, ING, Pearson, Pinterest, The New York Times, Nordstrom, and many more.
Written in Go, etcd has unrivaled cross-platform support, small binaries, and a thriving contributor community. It also integrates with existing cloud native tooling like Prometheus monitoring, which can track important metrics like latency from the etcd leader and provide alerting and dashboards. Other common use cases of etcd include storing important application configuration like database connection details or feature flags as key value pairs.
These values can be watched, allowing the application to reconfigure itself when changed. Advanced uses take advantage of the consistency guarantees to implement database leader elections or do distributed locking across a cluster of workers.
Source: cncf.io