Setting up CometBFT

Install CometBFT from Source

Full installation guidelines for CometBFT can be found on Github.

Note

You should now have the cometbft binary in build/.

Initialize the node

To initialize nodes, run the following commands:

# Node 1
cometbft init  -k "secp256k1" --home ./node1

# Node 2
cometbft init  -k "secp256k1" --home ./node2

Note

By default the output from init command is ~/.cometbft

Update config.toml

Update ports so they don’t conflict with other peers, ie:

tcp://127.0.0.1:26657 > tcp://127.0.0.1:36657

Set persistent_peers like so:

persistent_peers = "[email protected]:36656"

To get the peer id to use above, use these commands:

cometbft show-node-id --home ./node1
cometbft show-node-id --home ./node2

Update the genesis.json for all nodes

Make sure that:

1. the chain_id value is the same
2. max_gas is set to “-1” under “consensus_params”
3. the validator pubkeys types are the same: Should be “secp256k1”
4. allow_duplicate_ip value is “true” if getting duplicate connections error
5. addr_book_strict value is “false” if running locally
6. features is:

   "feature": {
               "vote_extensions_enable_height": "0",
               "pbts_enable_height": "1"
           }
   

7. validators entry has all nodes like so:

   "validators": [
           {
               "address": "044583E6D3EFDC706BA0AE434ADA527E4E82D079",
               "pub_key": {
                   "type": "tendermint/PubKeyEd25519",
                   "value": "Ww1JVYV8bZhv49VOvJ25iLsH5Uu/Sn6J3hBOZekifVo="
               },
               "power": "10",
               "name": ""
           },
           {
               "address": "634AB30AC3F8888AA4071C893036B22BC7A3D9A7",
               "pub_key": {
                   "type": "tendermint/PubKeyEd25519",
                   "value": "hEmXgh89RUOWmvL/XU7aQWKeBsKnZWHFyTJWsbeTvlU="
               },
               "power": "10",
               "name": ""
           }
       ]
   

Commands to start and reset the nodes

Start

cometbft start –home ./path_to_node

Reset

cometbft unsafe_reset_all –home ./path_to_node

Note

unsafe_reset_all only resets the data directory, not the genesis.json

Example genesis.json

{
  "genesis_time": "2024-08-28T15:28:48.066686Z",
  "chain_id": "3636",
  "initial_height": "0",
  "consensus_params": {
    "block": {
      "max_bytes": "4194304",
      "max_gas": "-1"
    },
    "evidence": {
      "max_age_num_blocks": "100000",
      "max_age_duration": "172800000000000",
      "max_bytes": "1048576"
    },
    "validator": {
      "pub_key_types": ["secp256k1"]
    },
    "version": {
      "app": "0"
    },
    "synchrony": {
      "precision": "500000000",
      "message_delay": "2000000000"
    },
    "feature": {
      "vote_extensions_enable_height": "1",
      "pbts_enable_height": "0"
    }
  },
  "validators": [
    {
      "address": "009D915D631DB0A3FEFB32685779D023153698DB",
      "pub_key": {
        "type": "tendermint/PubKeySecp256k1",
        "value": "AqSCYUYNrmyoGL6j6o3cKRt63fzpdv+LB3guvIdCNziU"
      },
      "power": "10",
      "name": ""
    },
    {
      "address": "09784D2BAA503337EAB2B1B023296324BA4827A6",
      "pub_key": {
        "type": "tendermint/PubKeySecp256k1",
        "value": "A9XFfycX13DcZWZHWTSoTA8Yu6Cappw0U7Ji5hbD8l5V"
      },
      "power": "10",
      "name": ""
    }
  ],
  "app_hash": ""
}