SYSTEM Cited by 1 source

etcd

etcd is a strongly consistent, distributed key-value store (CNCF graduated) using the Raft consensus protocol. It's the default backing store for the Kubernetes API server (stores the full cluster state) and is commonly deployed as a standalone consensus-data-store by applications that need distributed coordination (leader election, config, service discovery).

Stub page — expand on future etcd-internals sources.

Stateful-workload characterization

etcd pods need stable network identities across restarts so other cluster members can reliably reach them. Kubernetes StatefulSets provide this primitive; running etcd on ECS (which has no equivalent) requires custom container-startup code that dynamically updates cluster membership — described by Figma as "fragile and hard to maintain" and one of the motivating limitations of ECS for their migration.

Seen in

• sources/2024-08-08-figma-migrated-onto-k8s-in-less-than-12-months — cited as the "most egregious example" of ECS's lack of StatefulSets hurting them: Figma wrapped custom code around etcd container startup to dynamically update cluster membership. Migration to EKS lets them adopt the standard StatefulSet-based etcd deployment.