Create a Multi-Chain Network

Creating a Multi-Chain Network (which will allow us to later deploy our own VM).

A prerequisite for this tutorial is that you have a running node that is validating the primary network, for which the steps can find in the Add a Juneo Supernet validator node guide.

We will be using example code found in the juneojs-examples repository to deploy our Multi-Chain Network (which uses the library juneojs).

We recommend using JuneoJS on a system where you have access to a code editor.

Create a Multi-Chain Network (MCN)

First, please make sure that you have the latest version of NodeJS installed on your system.

If the version of NodeJS on your system is not up to date with the LTS version found at https://nodejs.org, the scripts in this guide will not be able to execute.

You will also need have the npm package ts-node installed, which will be used to execute the sample code provided in JuneoJS.

After verifying the information above, please download the juneojs-examples repository to your local machine. If you have git installed on your system, please execute the following in your command line:

git clone https://github.com/Juneo-io/juneojs-examples

The required files will be found in the directory juneojs-examples.

Next, please open juneojs-examples in a command line and execute the following command:

npm install

After this, open juneojs-examples in a code editor of your choice, create a .env file from the provided .env.example, and paste your mnemonic phrase in the MNEMONIC variable. Example:

MNEMONIC="raven whip pave toy benefit moment twin acid wasp satisfy crash april"

To perform the transactions required to deploy a MCN, you will need to have funds on the P-chain. In this tutorial, we will first be crossing assets from the JUNE-chain to the JVM-chain, and then from the JVM-chain to the P-chain.

In a command line window open in the root of the JuneoJS library, execute the following:

npx ts-node ./src/docs/crossJUNEtoJVM.ts

This will cross 1.1 JUNE from the JUNE-chain to the JVM-chain. After this, we will cross 1 JUNE from the JVM-chain to the P-chain by executing the following command:

npx ts-node ./src/docs/crossJVMtoP.ts

The next step is the MCN creation. Please execute the following in the command line:

npx ts-node ./src/supernet/createSupernet.ts

This will produce an output to the terminal containing your supernetID. Example: ZxTjijy4iNthRzuFFzMH5RS2BgJemYxwgZbzqzEhZJWqSnwh.

This is the id of the transaction that has created your MCN, and is the id of the MCN as well. Please save it as we will needed in the following steps.

Add a validator to the MCN

The next step is to perform the addSupernetValidator transaction.

If your MCN has no validators, all blockchains in that MCN will be inactive and will not be able to process transactions.

Please open the file ./src/supernet/addSupernetValidator.ts in your code editor, and update the following variables to contain the correct values. Example:

const nodeId: string = 'NodeID-B2GHMQ8GF6FyrvmPUX6miaGeuVLH9UwHr'
const supernetId: string = 'ZxTjijy4iNthRzuFFzMH5RS2BgJemYxwgZbzqzEhZJWqSnwhP'
const durationInDays: number = 20 // number of days you will validate your Supernet

We will keep the durationInDays variable the same. However, you may update it to a diffent value.

The variable durationInDays must be less than the amount of remaining days your node will be validating the Primary network.

If your node has 21 days (or a little over 20 days) left of Primary Network validation, you must set durationInDays to 20 or less.

Then, execute this file:

npx ts-node ./src/supernet/addSupernetValidator.ts

This will add our node as a validator for our MCN. However, we need to perform an additional step before our node can begin validating our MCN. First, please stop your node.

For users following the manual guide for setting up juneogo: please create a file titled config.json in the home directory.

For users following the install script guide for setting up juneogo: your config.json can already be found in the home directory.

For users who are running juneogo using juneogo-docker: your config file can be found in the juneogo-docker/juneogo/.juneogo/config.json directory.

In your config.json file, please include the configuration flag track-supernets, specifying the MCNs you want your node to track (in this case, the MCN you have just created).

Example:

{
 "track-supernets":"ZxTjijy4iNthRzuFFzMH5RS2BgJemYxwgZbzqzEhZJWqSnwhP"
}

After saving the file, you may run your node again.

For users following the manual juneogo setup guide, please execute the following :

./juneogo --config-file="./config.json"

For users following the install script juneogo setup guide, please restart the juneogo service:

systemctl --user restart juneogo.service

For users running juneogo using juneogo-docker, please re-start your node using docker compose.

Your node is now tracking the MCN you have just created.

If your node is the only node validating your MCN - once your node stops validating it, all chains within it will not be able to process transactions.

You would have to re-perform the Add MCN Validator transaction for your MCN chains to process transactions again.

You may now proceed to the next step: Deploy a VM.