​
Environment Variables

VariableDefaultDescription
CONCORDANCE_NODE_IDnode-{pid}Unique node identifier
CONCORDANCE_LISTEN127.0.0.1:4100Listen address (host:port)
CONCORDANCE_DATA_DIR./dataStorage directory for SQLite databases
CONCORDANCE_BOOTSTRAPfalseBootstrap as single-node leader
CONCORDANCE_JOIN—Address of existing cluster node to join
CONCORDANCE_API_KEYdevFull-access key (used by Diminuendo)
CONCORDANCE_AGENT_API_KEYauto-generatedRead-only key (used by Podium agents)

​
CLI Arguments

All environment variables can be overridden via CLI: 
concordance \
  --node-id=node1 \
  --listen=0.0.0.0:4100 \
  --data-dir=/var/lib/concordance \
  --bootstrap \
  --api-key=my-secret \
  --agent-key=agent-secret
To join an existing cluster: 
concordance \
  --node-id=node2 \
  --listen=0.0.0.0:4100 \
  --data-dir=/var/lib/concordance \
  --join=node1:4100

​
Raft Tuning

These are compiled defaults in service/raft/types.ts:
ParameterValueDescription
electionTimeoutMin150msMinimum election timeout
electionTimeoutMax300msMaximum (randomized per election)
heartbeatInterval50msMust be much less than election timeout
maxAppendEntries100Max entries per AppendEntries RPC
snapshotThreshold10,000Log entries before compaction
proposalTimeout5,000msMax wait for quorum commit

​
Diminuendo Integration

Diminuendo’s AppConfig.ts includes: 
CONCORDANCE_URL=http://127.0.0.1:4100     # Concordance cluster address
CONCORDANCE_API_KEY=dev                     # Shared with Concordance
CONCORDANCE_AGENT_API_KEY=dev-agent         # Passed to Podium agents via secrets
In dev mode, ConcordanceProcess spawns a single-node Concordance as a child process. In production, it’s a no-op — Concordance runs as a separate cluster.