Add and remove IBFT 2.0 validators

This example walks through adding and removing an IBFT 2.0 validator.

Prerequisites

• IBFT 2.0 network as configured in the IBFT 2.0 tutorial

Add a validator

1. Create directories

Create a working directory and a data directory for the new node that needs to be added:

mkdir -p Node-5/data

2. Start the node

Change into the working directory for the new Node-5 and start the node, specifying the Node-1 enode URL as the bootnode:

besu --data-path=data --genesis-file=../genesis.json --bootnodes=<Node-1 Enode URL> --p2p-port=30307 --rpc-http-enabled --rpc-http-api=ETH,NET,IBFT --host-allowlist="*" --rpc-http-cors-origins="all" --rpc-http-port=8549

The command line specifies:

• The data directory for Node-5 using the --data-path option.
• A different port to Node-1 for P2P discovery using the --p2p-port option.
• A different port to Node-1 for HTTP JSON-RPC using the --rpc-http-port option.
• The enode URL of Node-1 using the --bootnodes option.
• Other options as for Node-1.

3. Copy the address of the node

Copy the address of the node. You can find the address in the logs when starting the new node:

2021-05-28 09:49:00.881+10:00 | main | INFO  | DefaultP2PNetwork | Node address 0x90626e6a67445aabf1c0615410d108d4733aa90b

Or use the public-key export-address subcommand:

besu --data-path=IBFT-Network/Node-5/data public-key export-address

0x90626e6a67445aabf1c0615410d108d4733aa90b

4. Propose adding the new validator

Propose adding the new validator from more than half the number of current validators, using ibft_proposeValidatorVote, specifying the address of the proposed validator and true:

curl -X POST --data '{"jsonrpc":"2.0","method":"ibft_proposeValidatorVote","params":["0x90626e6a67445aabf1c0615410d108d4733aa90b", true], "id":1}' http://127.0.0.1:8545

{
  "jsonrpc":"2.0",
  "id":1,
  "result":true
}

Repeat the proposal process for this candidate node from at least two of the other nodes.

5. Verify the addition of the new validator

Verify that the new validator is now in the list of validators using ibft_getValidatorsByBlockNumber:

curl -X POST --data '{"jsonrpc":"2.0","method":"ibft_getValidatorsByBlockNumber","params":["latest"], "id":1}' http://127.0.0.1:8545

["0x189d23d201b03ae1cf9113672df29a5d672aefa3", "0x2aabbc1bb9bacef60a09764d1a1f4f04a47885c1", "0x44b07d2c28b8ed8f02b45bd84ac7d9051b3349e6", "0x4c1ccd426833b9782729a212c857f2f03b7b4c0d", "0x90626e6a67445aabf1c0615410d108d4733aa90b"]

The list of validators contains 5 addresses now.

Remove a validator

The process for removing a validator is similar to adding a validator starting from step 2, except you specify false as the second parameter of ibft_proposeValidatorVote.