Leaderless by design
Every peer is equal. Send a request to any node and it becomes the coordinator—no elections, terms, or dedicated write leader.
DISTRIBUTED SYSTEMS, TRIMMED TO THE ESSENTIALS
Small crew.
Shared truth.
A compact, leaderless JSON key-value store that keeps three Rust nodes in lockstep—through crashes, partitions, and rough water.
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03equal peers
02make quorum
1.77MiB median / node
41.8781° N
87.6298° W
87.6298° W
ATOMIC REGISTER
COURSE 042°
COURSE 042°
01 / THE IDEA
The calm inside
distributed systems.
SailboatKV narrows the problem on purpose: one inspectable protocol, one fixed crew, and one clear consistency promise.
RS Written in Rust · Tokio + Axum
{ }
Purpose-built JSON API
Three deliberate operations: GET, PUT, and DELETE. Values are validated JSON objects; tombstones keep deletes ordered.
CP, without ambiguity
A minority returns 503 instead of guessing. Successful reads and writes always intersect a majority.
02 / THE PROTOCOL
Every request
meets the crew.
A write is not successful because one node saw it. It is successful only after durable majority acknowledgement.
- 1Query quorumFind the newest observed version
- 2Choose versionOrder by (counter, node ID)
- 3Replicate durablyLocal + peer persistence in parallel
- 4Return 201Only after the majority confirms
01NODE Acoordinator
02NODE Backnowledged
03NODE Cequal peer
PUT /boats
2 / 3QUORUM
03 / CONSISTENCY
Writes may race.
Truth never does.
NODE A“ALCYONE”
VERSION(42, A)
NODE B“CALYPSO”
VERSION(42, B)
✓
DETERMINISTIC WINNER
“CALYPSO”
Every node converges on the same totally ordered version.
Linearizable reads
A completed read can’t return a value older than an earlier completed write.
Monotonic state
Older or equal versions are never allowed to overwrite newer records.
Ordered deletes
Tombstones travel through the same quorum path, so deletion never moves backward.
04 / FAILURE MODE
When the network breaks,
safety stays intact.
SailboatKV chooses consistency over minority availability. Two nodes keep sailing; one isolated node stops safely.
MAJORITY PARTITION
01NODE A
QUORUM
02NODE B
200 / 201Progress continues
NETWORK PARTITION
ISOLATED MINORITY
03NODE C
503Stops safely
“No quorum means no stale answer.
That’s the contract—not an outage bug.
05 / DURABILITY + RECOVERY
Built to
come back.
Acknowledged state crosses a deliberate persistence boundary. Stale peers heal when they return—without replaying a log.
05durability boundaries
fault-injected in tests
fault-injected in tests
ATOMIC SNAPSHOT REPLACEMENTSTORE.JSON
01{ }
Write tempComplete JSON snapshot
02↻
File fsyncBytes reach stable storage
03⇄
Atomic renameReplace committed state
04⌁
Directory fsyncLock in the rename
NEWOLD
READ REPAIRThe latest value catches up a stale peer on the way back in.
SELF-HEALING
06 / MEASURED PERFORMANCE
Reads travel light.
Fresh three-node Docker clusters · 10,000 measured linearizable reads · median of five runs on Apple Silicon.
01 THROUGHPUT
3,045.04
operations / second
SailboatKV 3,045etcd gateway 2,924
02 P99 LATENCY
0.462 ms
20.1% lower in this workload
03 MEDIAN MEMORY
1.77 MiB
≈12.6× lower per container
! A deliberately narrow native HTTP vs. etcd HTTP/JSON gateway comparison—not a claim of general superiority.
07 / GET UNDERWAY
One command.
Three endpoints.
Docker, Cargo, or Nix. Every package starts the same fixed three-node cluster with the same observable guarantees.
:3001 :3002 :3003
24automated tests
01external chaos suite
64RPC connection cap
~/SailboatKVzsh
$ docker compose -f docker/docker-compose.yml \
up --build --detach --wait
✓ Network sailboat created
✓ Container node-1 healthy
✓ Container node-2 healthy
✓ Container node-3 healthy
QUORUM ONLINE · 3 ACTIVE NODES
$ curl localhost:3003/boats
{ "name": "Alcyone", "length": 32 }
