dchain/deploy/prod

DChain production deployment

Turn-key-ish stack: 3 validators + Caddy TLS edge + optional Prometheus/Grafana, behind auto-HTTPS.

Prerequisites

• Docker + Compose v2
• A public IP and open ports 80, 443, 4001 (libp2p) on every host
• DNS A-record pointing DOMAIN at the host running Caddy
• Basic familiarity with editing env files

Layout (single-host pilot)

                   ┌─ Caddy :443 ── TLS terminate ──┬─ node1:8080 ──┐
 internet ────────→│                                ├─ node2:8080  │ round-robin /api/*
                   └─ Caddy :4001 (passthrough)     └─ node3:8080  │ ip_hash /api/ws
                   ...
                   Prometheus → node{1,2,3}:8080/metrics
                   Grafana ← Prometheus data source

For a real multi-datacentre deployment, copy this whole directory onto each VPS, edit docker-compose.yml to keep only the node that runs there, and put Caddy on one dedicated edge host (or none — point clients at one node directly and accept the lower availability).

First-boot procedure

1. Generate keys for each validator. Easiest way:

   # On any box with the repo checked out
   docker build -t dchain-node-slim -f deploy/prod/Dockerfile.slim .
   mkdir -p deploy/prod/keys
   for i in 1 2 3; do
     docker run --rm -v "$PWD/deploy/prod/keys:/out" dchain-node-slim \
       /usr/local/bin/client keygen --out /out/node$i.json
   done
   cat deploy/prod/keys/node*.json | jq -r .pub_key  # → copy into DCHAIN_VALIDATORS
   

2. Configure env files. Copy node.env.example to node1.env, node2.env, node3.env. Paste the three pubkeys from step 1 into DCHAIN_VALIDATORS in ALL THREE files. Set DOMAIN to your public host.

3. Start the network:

   DOMAIN=dchain.example.com docker compose up -d
   docker compose logs -f node1   # watch genesis + first blocks
   

   First block is genesis (index 0), created only by node1 because it has the --genesis flag. After you see blocks #1, #2, #3… committing, edit docker-compose.yml and remove the --genesis flag from node1's command section, then docker compose up -d node1 to re-create it without that flag. Leaving --genesis in makes no-op on a non-empty DB but is noise in the logs.

4. Verify HTTPS and HTTP-to-HTTPS redirect:

   curl -s https://$DOMAIN/api/netstats | jq
   curl -s https://$DOMAIN/api/well-known-contracts | jq
   

   Caddy should have issued a cert automatically from Let's Encrypt.

5. (Optional) observability:

   GRAFANA_ADMIN_PW=$(openssl rand -hex 24) docker compose --profile monitor up -d
   # Grafana at http://<host>:3000, user admin, password from env
   

   Add a "Prometheus" data source pointing at http://prometheus:9090, then import a dashboard that graphs:

   • dchain_blocks_total (rate)
   • dchain_tx_submit_accepted_total / rejected_total
   • dchain_ws_connections
   • dchain_peer_count_live
   • rate(dchain_block_commit_seconds_sum[5m]) / rate(dchain_block_commit_seconds_count[5m])

Common tasks

Add a 4th validator

The new node joins as an observer via --join, then an existing validator promotes it on-chain:

# On the new box
docker run -d --name node4 \
  --volumes chaindata:/data \
  -e DCHAIN_ANNOUNCE=/ip4/<public-ip>/tcp/4001 \
  dchain-node-slim \
  --db=/data/chain --join=https://$DOMAIN --register-relay

Then from any existing validator:

docker compose exec node1 /usr/local/bin/client add-validator \
  --key /keys/node.json \
  --node http://localhost:8080 \
  --target <NEW_PUBKEY>

The new node starts signing as soon as it sees itself in the validator set on-chain — no restart needed.

Upgrade without downtime

PBFT tolerates f faulty nodes out of 3f+1. For 3 validators that means zero — any offline node halts consensus. So for 3-node clusters:

1. docker compose pull && docker compose build on all three hosts first.
2. Graceful one-at-a-time: docker compose up -d --no-deps node1, wait for /api/netstats to show it catching up, then do node2, then node3.

For 4+ nodes you can afford one-at-a-time hot rolls.

Back up the chain

docker run --rm -v node1_data:/data -v "$PWD":/bak alpine \
  tar czf /bak/dchain-backup-$(date +%F).tar.gz -C /data .

Restore by swapping the file back into a fresh named volume before node startup.

Remove a bad validator

Same as adding but with remove-validator. Only works if a majority of CURRENT validators cosign the removal — intentional, keeps one rogue validator from kicking others unilaterally (see ROADMAP P2.1).

Security notes

• /metrics is firewalled to internal networks by Caddy. If you need external scraping, add proper auth (Caddy basicauth or mTLS).
• All public endpoints are rate-limited per-IP via the node itself — see api_guards.go. Adjust limits before releasing to the open internet.
• Each node runs as non-root inside a read-only rootfs container with all capabilities dropped. If you need to exec into one, docker compose exec --user root nodeN sh.
• The Ed25519 key files mounted at /keys/node.json are your validator identities. Losing them means losing your ability to produce blocks; get them onto the host via your normal secret-management (Vault, sealed- secrets, encrypted tarball at deploy time). Never commit them to git.

Troubleshooting

Symptom	Check
Caddy keeps issuing failed to get certificate	Is port 80 open? DNS A-record pointing here? docker compose logs caddy
New node can't sync: FATAL: genesis hash mismatch	The --db volume has data from a different chain. docker volume rm nodeN_data and re-up
Chain stops producing blocks	docker compose logs nodeN | tail -100; look for SLOW AddBlock or validator silence
/api/ws returns 429	Client opened > WSMaxConnectionsPerIP (default 10). Check ws.go for per-IP cap
Disk usage growing	Background vlog GC runs every 5 min. Manual: docker compose exec nodeN /bin/sh -c 'kill -USR1 1' (see StartValueLogGC)