proxmox/docs/archive/QBFT_VALIDATOR_RECOGNITION_ISSUE.md

QBFT Validator Recognition Issue

Date: 2025-12-20
Critical Issue: Besu is not recognizing validators from genesis extraData

Problem

• ✅ Genesis extraData is correct (contains 5 validator addresses in QBFT format)
• ✅ Validator keys are deployed correctly
• ✅ Validator addresses match extraData
• ✅ Network connectivity is good
• ❌ Besu returns empty validator set: qbft_getValidatorsByBlockNumber("latest") returns []
• ❌ Validators are trying to sync instead of produce blocks
• ❌ No QBFT consensus activity

Key Finding

Query Result:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": []
}

An empty validator set means Besu is not extracting validator addresses from the genesis extraData, even though:

• Genesis block exists and has correct extraData
• extraData contains 5 validator addresses in RLP-encoded QBFT format
• All validator node addresses match addresses in extraData

Possible Root Causes

1. Besu Not Parsing Genesis extraData

• Besu may require explicit configuration to parse QBFT extraData
• Or there's a bug/issue with extraData parsing in Besu 23.10.0

2. Missing QBFT Configuration Option

• There may be a required config option to enable QBFT validator detection
• Some versions require explicit validator configuration even with genesis extraData

3. Genesis Block Initialization Issue

• The genesis block exists, but Besu may not have processed the extraData correctly
• This could be a database initialization issue

4. QBFT vs IBFT2 Confusion

• Some Besu versions may use IBFT2 API instead of QBFT API
• But IBFT2 API also returned "Method not enabled"

Next Steps

1. Check Besu 23.10.0 QBFT Documentation: Verify if there are special requirements for QBFT validator recognition
2. Test with a simpler genesis: Try with a minimal QBFT genesis to isolate the issue
3. Check Besu GitHub Issues: Look for known issues with QBFT validator recognition in Besu 23.10.0
4. Try explicit validator configuration: Even though it should be auto-detected, try explicitly configuring validators

Configuration Status

• Besu Version: 23.10.0
• QBFT Config in Genesis: ✅ Present (blockperiodseconds: 2, epochlength: 30000)
• extraData Format: ✅ Correct (RLP-encoded QBFT format)
• RPC Enabled: ✅ With QBFT API
• Validator Keys: ✅ Present and matching

Impact

Blocks cannot be produced because Besu doesn't recognize any validators. Without validators, QBFT consensus cannot start, and the network will remain at block 0 indefinitely.