ultima_cluster

SMR cluster implementation on top of openraft.

Status: M5 — OutputHandler at-least-once dispatch (steady-state + leader-transition replay). Builds on M4's uc_client SDK + ring wrap-fix. See docs/superpowers/specs/2026-05-10-ultima-cluster-design.md for the canonical design and docs/tasks/ for per-milestone records.

Workspace

• uc_protocol — wire spec (no_std-friendly): ring buffer primitives (SPSC / MPSC / Broadcast), cnc.dat layout, per-RPC frame types, liveness + handshake helpers.
• uc_service — service-side SDK: sync StateMachine (apply, query, snapshot) + async leader-only OutputHandler::on_committed with at-least-once durability via node-side output_progress.state. Ships the uc_service::ultima_db adapter (StoreStateMachine).
• uc_node — cluster engine (Raft, log storage, QUIC inter-node network, shmem IPC owner: instance.lock, cnc.dat, service rings, liveness ticker, service watcher).
• uc_client — local-shmem client SDK (Client::{connect, submit, query_linearizable, query_snapshot, shutdown}; session liveness; node
  • service stall detection; NotLeader hint surfaced to callers).

Build & test

cargo build --workspace
cargo test --workspace
cargo clippy --workspace --all-targets -- -D warnings

See CLAUDE.md for orientation.