Kamado Pool

A solo Bitcoin mining pool built on a patched fork of CKPool, with a Go middleware API, real-time Svelte dashboard, and full StartOS integration.

Kamado exists because existing CKPool wrappers read only a handful of periodic stats files and miss most of CKPool's rich runtime data. Kamado talks directly to CKPool's Unix socket API, subscribes to bitcoind via both RPC and ZMQ, tails CKPool's log for block-solve events, and merges everything into a single live snapshot that the dashboard consumes over WebSocket.

Architecture

                         ┌──────────────────────────────┐
  Miners ──stratum:3333──►  ckpool-solo (C, patched)    │
                         │    │ Unix socket    │ log    │
                         │    ▼                ▼        │
                         │  kamado-api (Go)             │
                         │    │ RPC+ZMQ    ▲ HTTP/WS    │
                         │    ▼            │            │
                         │  bitcoind     Browser :8080  │
                         └──────────────────────────────┘
Component Language Role
ckpool/ C Stratum server, share validation, vardiff, block assembly and submission
api/ Go Socket client, bitcoind RPC, ZMQ subscriber, log tailer, state aggregator, REST + WebSocket API, SQLite persistence
ui/ Svelte 5 Real-time dashboard with pool overview, miner stats, block history, best share tracking, transaction accelerator

The Go binary embeds the built Svelte app via //go:embed and serves it at / — a single static binary with no external web server.

Improvements Over Upstream CKPool

CKPool is a high-performance stratum server, but it has no web interface and limited observability. Kamado adds a complete operational layer on top:

Patches Applied to CKPool

Seven patches are applied to upstream commit cfb0f83 (which itself includes the workbase_id fix, extended ESP32/NerdMiner timeouts, configurable dropidle, and vardiff improvements):

Patch Purpose
0001 Expose bestever (all-time best share) in runtime socket JSON alongside bestdiff (current round)
0002 Always reply on the listener socket so kamado-api gets responses in btcsolo mode
0003 Return share errors as proper Stratum [code, msg, null] arrays per the Slush pool protocol spec
0004 Expose per-worker share counts (accepted/rejected) in runtime socket JSON
0005 Log ZMQ-to-notify latency for block-update performance monitoring
0006 Expose raw reject count in pool stats
0007 Replace hardcoded "ckpool" branding in the coinbase scriptSig with "kamado" (same 6 bytes, consensus-safe)

Middleware API

The Go API (kamado-api) bridges CKPool's Unix socket protocol, bitcoind's JSON-RPC, and ZMQ into a unified HTTP/WebSocket interface:

  • Socket client — CKPool uses a 4-byte length-prefixed binary protocol on a Unix domain socket. kamado-api opens a fresh connection per request and queries pool, user, worker, and client state in real time.
  • State aggregator — Merges socket responses, bitcoind chain info, ZMQ events, and log-tailed block solves into a single thread-safe snapshot, refreshed on a configurable interval.
  • ZMQ subscriber — Listens to bitcoind's hashblock topic for sub-second block notifications, triggering an immediate state refresh. Falls back to RPC polling if ZMQ is unavailable.
  • Log tailer — Watches CKPool's log file (inotify-based) for "Solved and confirmed block" lines, extracts height and hash, enriches via bitcoind RPC (reward, confirmations), and records to SQLite.
  • Block reconciliation — On startup, cross-references in-memory blocks with the database and bitcoind to detect orphans and fill gaps.
  • Chain reorg detection — Scoped to the active chain; clears stale state on tip changes.
  • SQLite persistence — Blocks, accelerated transactions, and log cursor survive restarts. Non-fatal if unavailable (in-memory ring fallback).
  • Transaction accelerator — Inspects the current block template to find the marginal (lowest fee-rate) transaction, calls prioritisetransaction to boost a target tx, and reports the displaced fee as revenue impact. Includes a hard cap (2000 sat/vB) and lifecycle cleanup.

Stratum TLS

Optional encrypted stratum via stunnel. CKPool binds two stratum sockets — a public plaintext port and a loopback-only internal port. Stunnel terminates TLS on the external port and forwards decrypted traffic to the internal bind. CKPool tags connections by serverurl index (server === 1 means TLS), which the dashboard reads to display a lock icon next to encrypted miners — no source-IP heuristics needed.

The TLS certificate is auto-generated on first start with broad SAN coverage (.local, .embassy, .onion, .lan, .home.arpa, .internal) so miner firmware that validates the SAN against the connection hostname (e.g. AxeOS with mbedtls) works without manual cert pinning. A version marker triggers automatic regeneration when the cert format changes.

Dashboard

The Svelte 5 dashboard connects via WebSocket for real-time push updates (no polling in normal operation) and includes:

  • Pool overview — Hashrate (1m/5m/1h/24h), uptime, workers online, shares accepted/rejected, expected time to block, round effort
  • Hashrate chart — Interactive multi-window visualization
  • Miners table — Per-user and per-worker stats: hashrate, difficulty, latency, best shares, idle detection
  • Hardware detection — Parses stratum user-agent strings to identify miner hardware (Bitaxe, Bitaxe Hex, NerdMiner, NerdAxe, NerdQAxe, NerdOCTAXE, NerdEKO, NerdNOS, PiAxe, QAxe, 0xAxe, LeafMiner, and more). Open-source hardware is flagged with a star badge so operators can see their fleet composition at a glance.
  • TLS badges — Miners connected via the encrypted stratum port display a lock icon in the miners table, derived from CKPool's server field (no IP heuristics).
  • User/worker detail pages — Deep dive into individual miner stats, cumulative work, and luck
  • Block history — Found blocks with height, hash, reward, solving worker, chain name, orphan status
  • Best share leaderboard — "This round" and "all-time" tracking with per-worker breakdown and glowing difficulty range indicators
  • Transaction accelerator — Boost transactions via prioritisetransaction with marginal fee displacement analysis showing the revenue impact of each boost
  • Block-found animation — Celebratory toast on solve events
  • Health banners — Live status indicators for CKPool, bitcoind, ZMQ, and submit-gap diagnostics
  • Block-update latency — Tracks and displays average, last, and wasted-work latency for block notifications so operators can tune ZMQ and polling
  • Shares bar — Accepted/rejected/stale share summary with ratio visualization
  • Custom mempool explorer — Transaction and block links can point at a self-hosted mempool instance instead of the public mempool.space
  • Mobile responsive — Full breakpoint coverage for phone and tablet
  • Donation footer — BTC address with hover QR code

Reliability

  • Dual block notification — ZMQ hashblock for instant detection + RPC polling as fallback. Both run simultaneously; every second of stale work in solo mode is hashrate burned on a dead block.
  • ckpool kill-on-failure — When bitcoind becomes unreachable, kamado-api kills ckpool so miners can failover to another pool. ckpool restarts automatically when bitcoind recovers.
  • Deferred RPC — Dashboard RPCs wait until the ckpool notifier completes on tip change to prioritize system resources for block reconstruction and validation.
  • Log cursor persistence — The tailer's file offset is stored in SQLite so block-solve detection resumes correctly after restart.
  • Warm-up resilience — The ckpool socket client handles transient EOFs during startup gracefully instead of crashing.

API Reference

Method Route Description
GET /api/health Pool + bitcoind health, submit-gap tracking, ZMQ staleness
GET /api/pool Pool stats, hashrate windows, chain info, network hashrate
GET /api/users All users: shares, best diff, idle status
GET /api/workers All workers: hashrate, best share, share counts
GET /api/clients Active stratum sessions: useragent, IP, assigned difficulty
GET /api/blocks Recent solved blocks: height, hash, reward, orphan status
GET /api/snapshot Full merged snapshot (everything above combined)
GET /api/ws WebSocket: push on every state refresh + immediate on block solve
GET /api/admin/debug-blocks In-memory vs. DB block discrepancy troubleshooting
POST /api/admin/reset-latency Zero all block-update latency counters
POST /api/admin/ack-best Acknowledge new best share (UI state marker)
POST /api/admin/reset-ack-best Reset best share acknowledgment
POST /api/accelerate Boost a transaction via prioritisetransaction
POST /api/accelerate/cancel Cancel a previously boosted transaction
POST /api/accelerate/max Boost a tx with a new feerate 2x the mempool highest (capped at 2000 sat/vB)
GET /api/accelerate/list List all currently boosted transactions

Development

Prerequisites

  • Go 1.22+
  • Node.js 22+
  • Docker and Docker Compose
  • bitcoind (for regtest testing)

Quick Start

cp .env.example .env          # set bitcoind RPC credentials
make up                       # build images + start ckpool + api

The dashboard is at http://localhost:8080. Point a miner at stratum+tcp://localhost:3333 with a Bitcoin address as the username.

Make Targets

Target Description
make up Build and start all services
make down Stop all services
make logs Tail ckpool + api logs
make api Build the kamado/api:dev image
make ckpool Build the kamado/ckpool:dev image
make api-test Run Go tests with race detector
make ui Build Svelte dashboard to ui/dist
make ui-dev Start Vite dev server (:5173, proxies /api to :8080)
make ui-check Run svelte-check type diagnostics
make clean Remove data, build artifacts, and volumes

Environment Variables

Variable Default Required Description
BITCOIN_RPC_URL yes bitcoind RPC endpoint (e.g. http://127.0.0.1:8332)
BITCOIN_RPC_USER yes RPC username
BITCOIN_RPC_PASSWORD yes RPC password
LISTEN_ADDR :8080 no HTTP bind address
CKPOOL_SOCKDIR /run/ckpool no CKPool Unix socket directory
CKPOOL_LOGFILE /var/log/ckpool/ckpool.log no CKPool log path for block-solve detection
DB_PATH /var/lib/kamado/kamado.db no SQLite database path
POLL_INTERVAL 5s no State refresh interval
BITCOIN_ZMQ_BLOCK (disabled) no ZMQ hashblock endpoint (e.g. tcp://127.0.0.1:28332)
BITCOIN_RPC_TIMEOUT 10s no RPC call timeout
MEMPOOL_BASE_URL (mempool.space) no Custom mempool explorer URL

UI Development

make ui-dev

Starts Vite on :5173 with hot reload. API calls are proxied to :8080 — run make up first so the backend is available.

Testing

make api-test                          # Go unit tests (race detector enabled)
cd api && go test -race ./...          # same thing without Make
./test/regtest_smoke.sh                # Full regtest integration test

Go Unit Tests

The test suite covers the critical mining path with 38 tests across 5 packages:

Package Tests Coverage
bitcoind RPC retry logic (transient 503s, warmup errors, semantic errors, exhausted retries), coinbase reward extraction Ensures the RPC client retries on transport failures and bitcoind warmup but fails fast on semantic errors
ckpool Socket client ping, pool stats parsing, client listing, dial error handling Validates the 4-byte length-prefixed binary protocol against a mock Unix socket
logmon Line parsing (solved blocks, submitting variants, diff reset, unrelated lines), tailer run (basic read, cursor resume after restart, log rotation) Covers the full log tailer lifecycle including inotify-based file watching
state Block reconciliation (chain-scoped filtering, genuine reorgs, RPC errors, legacy blocks, cross-network), block ingestion (new blocks, dedup, chain stamping) Ensures reorg detection never false-orphans blocks from other chains
store SQLite roundtrips (insert, dedup, orphan marking, enrichment updates, enrichment queries, chain column migration, KV store) Validates schema migrations and all persistence operations

Regtest Smoke Test

The smoke test runs two phases on regtest:

  1. Log-inject path — Injects a synthetic block-solve line into ckpool's log, verifies the tailer detects it, enriches it via bitcoind RPC, and surfaces it at /api/blocks. Quick, no ckpool binary needed.
  2. Full stratum path — Starts ckpool, connects a Python stratum miner, mines a real block, verifies the coinbase contains the "kamado" tag and the configured pool identifier, validates that bitcoind accepted the block with confirmations > 0, and checks that the block validation log shows correct chain acceptance.

The smoke test auto-builds ckpool from the pinned upstream source with patches applied if not cached (build cached in ~/.cache/kamado-dev/).

Project Structure

api/
  cmd/kamado-api/       Main entry point
  internal/
    accelerator/        Transaction priority boosting via prioritisetransaction
    bitcoind/           Minimal JSON-RPC client with retry logic
    ckpool/             Unix socket protocol client (4-byte LE framing)
    config/             Environment variable loading and validation
    httpapi/            REST routes, WebSocket hub, SPA handler
    logmon/             inotify-based CKPool log tailer
    state/              Snapshot aggregator, block reconciliation, reorg detection
    store/              SQLite persistence (blocks, KV, accelerated txs, cursor)
    webui/              Embedded Svelte assets (go:embed)
    zmqmon/             ZMQ hashblock subscriber
ckpool/
  patches/              Seven-patch series applied to upstream
  config/               ckpool.conf.template (sed-rendered at startup)
  Dockerfile            Two-stage ckpool build
ui/
  src/
    lib/                Svelte 5 components (dashboard, miners, blocks, accelerator)
    format.ts           Hardware detection, hashrate formatting, address parsing
    snapshot.svelte.ts  Global reactive store (WebSocket + REST fallback)
    types.ts            TypeScript interfaces for API responses
test/
  regtest_smoke.sh      Two-phase integration test (log-inject + full stratum)

StartOS

The StartOS wrapper packages Kamado Pool as an .s9pk for StartOS 0.3.5.1 with health checks, configuration, actions, backup/restore. Porting to StartOS 0.4.0 is in progress.

Upstream

CKPool by Con Kolivas — https://bitbucket.org/ckolivas/ckpool

Pinned commit: cfb0f83b70d7b382b85d2bd0710cf4cb2dda4007

License

GPL-3.0 — see LICENSE.

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