Node

Become An GEMNODE Node

Adding Subnet Validator

The newly created Subnet requires validators to validate the transactions on the Subnet's every blockchain. Now we will write the code in addSubnetValidator.js to add validators to the Subnet. Only transactions signed by the threshold (here 1) number of Subnet owners will be accepted to add validators. The Subnet owners which will sign this transaction is passed as the subnetAuth parameter. It is an array of indices, representing the Subnet owners from the array of addresses that we passed earlier in the createSubnetTx().

The arguments for the AvalancheJS API call for buildAddSubnetValidatorTx() is explained with the help of comments. All the transaction calls of AvalancheJS starting with build will return an unsigned transaction. We then have to sign it with our key chain and issue the signed transaction to the network.

const args = require("yargs").argv
const {
  platform,
  info,
  pKeyChain,
  pAddressStrings,
  utxoSet,
  BN,
} = require("./importAPI.js")

async function addSubnetValidator() {
  let {
    nodeID = await info.getNodeID(),
    startTime,
    endTime,
    weight = 20,
    subnetID,
  } = args

  const pAddresses = pKeyChain.getAddresses()

  // Creating Subnet auth
  const subnetAuth = [[0, pAddresses[0]]]

  // Creating unsgined tx
  const unsignedTx = await platform.buildAddSubnetValidatorTx(
    await utxoSet(), // set of utxos this tx will consume
    pAddressStrings, // from
    pAddressStrings, // change
    nodeID, // node id of the validator
    new BN(startTime), // timestamp after which validation starts
    new BN(endTime), // timestamp after which validation ends
    new BN(weight), // weight of the validator
    subnetID, // Subnet id for validation
    undefined, // memo
    undefined, // asOf
    subnetAuth // Subnet owners' address indices signing this tx
  )

  // signing unsgined tx with pKeyChain
  const tx = unsignedTx.sign(pKeyChain)

  // issuing tx
  const txId = await platform.issueTx(tx)
  console.log("Tx ID: ", txId)
}

addSubnetValidator()

We have to pass command-line arguments like nodeID, startTime, endTime, weight and subnetID while calling the command. If we do not pass any nodeID, then by default it will use ID corresponding to the URI in the config.js by calling the info.getNodeID() API from AvalancheJS. Similarly, the default weight will be 20, if not passed. You can run this program now with the following command.

node addSubnetValidator.js \
--subnetID <YOUR_SUBNET_ID> \
--startTime $(date -v +5M +%s) \
--endTime $(date -v +14d +%s)

We will keep the start time 5 minutes later than the current time. This $(date -v +5M +%s) will help to achieve the same. But you can put any timestamp in seconds there, given it is 20s later than the current time.

Whitelisting Subnet from the Node​

Subnet owners can add any node to their Subnet. That doesn't mean the nodes start validating their Subnet without any consent. If a node wants to validate the newly added Subnet, then it must restart its avalanchego binary with the new Subnet being whitelisted.

avalanche-network-runner control restart-node \
--request-timeout=3m \
--endpoint="0.0.0.0:8080" \
--node-name node1 \
--avalanchego-path ${HOME}/subnet-evm-demo/avalanchego/build/avalanchego \
--whitelisted-subnets="<SUBNET_ID>"

Once the node has restarted, it will again be re-assigned to a random API port. We have to update the config.js file with the new port.