Intermediate

How to build your first Subnet

This tutorial is a guide on how to create and deploy your first Subnet using Avalanche-CLI. It includes steps on installation of Avalanche-CLI, creating a Subnet configuration (Ethereum Virtual Machine based Subnet), choosing the Subnet-EVM version, configuring gas fees, airdrop, precompiles, etc. The tutorial also covers deployment of Subnets locally, by booting a five-node Avalanche network on the machine. The process may take a few minutes to run, and if all goes well, the command output should indicate the network is ready to use.

The best way to get started is by jumping in and deploying your first Subnet.

This tutorial walks you through the process of using Avalanche-CLI for the first time by creating a Subnet, deploying it to the local network, and connecting to it with MetaMask.

Installation​

The fastest way to install the latest Avalanche-CLI binary is by running the install script:

curl -sSfL https://raw.githubusercontent.com/ava-labs/avalanche-cli/main/scripts/install.sh | sh -s

The binary installs inside the ~/bin directory. If the directory doesn’t exist, it will be created.

You can run all of the commands in this tutorial by calling ~/bin/avalanche.

You can also add the command to your system path by running

export PATH=~/bin:$PATH

If you add it to your path, you should be able to call the program anywhere with just avalanche. To add it to your path permanently, add an export command to your shell initialization script (ex: .bashrc or .zshrc).

For more detailed installation instructions, see Avalanche-CLI Installation

Create Your Subnet Configuration​

This tutorials teaches you how to create an Ethereum Virtual Machine (EVM) based Subnet. To do so, you use Subnet-EVM, Avalanche’s Subnet fork of the EVM. It supports airdrops, custom fee tokens, configurable gas parameters, and multiple stateful precompiles. To learn more, take a look at Subnet-EVM. The goal of your first command is to create a Subnet-EVM configuration.

The Subnet command suite provides a collection of tools for developing and deploying Subnets.

The Subnet Creation Wizard walks you through the process of creating your Subnet. To get started, first pick a name for your Subnet. This tutorial uses mySubnet, but feel free to substitute that with any name you like. Once you’ve picked your name, run

avalanche subnet create mySubnet

The following sections walk through each question in the wizard.

Choose Your VM​

Select SubnetEVM.

Enter Your Subnet’s ChainID​

Choose a positive integer for your EVM-style ChainID.

In production environments, this ChainID needs to be unique and not shared with any other chain. You can visit chainlist to verify that your selection is unique. Because this is a development Subnet, feel free to pick any number. Stay away from well-known ChainIDs such as 1 (Ethereum) or 43114 (Avalanche C-Chain) as those may cause issues with other tools.

Token Symbol​

Enter a string to name your Subnet’s native token. The token symbol doesn’t necessarily need to be unique. Example token symbols are AVAX, JOE, and BTC.

Subnet-EVM Version​

Select Use latest version.

Gas Fee Configuration​

This question determines how to set gas fees on your Subnet.

Select Low disk use / Low Throughput 1.5 mil gas/s (C-Chain's setting).

Airdrop​

Select Airdrop 1 million tokens to the default address (do not use in production).

This address’s private key is well-known, so DO NOT send any production funds to it. Attackers would likely drain the funds instantly.

When you are ready to start more mature testing, select Customize your airdrop to distribute funds to additional addresses.

Precompiles​

Precompiles are Avalanche’s way of customizing the behavior of your Subnet. They’re strictly an advanced feature, so you can safely select No for now.

Wrapping Up​

If all worked successfully, the command prints Successfully created subnet configuration.

You’ve successfully created your first Subnet configuration. Now it’s time to deploy it.

Deploying Subnets Locally​

To deploy your Subnet, run

avalanche subnet deploy mySubnet

Make sure to substitute the name of your Subnet if you used a different one than mySubnet.

Next, select Local Network.

This command boots a five node Avalanche network on your machine. It needs to download the latest versions of AvalancheGo and Subnet-EVM. The command may take a couple minutes to run.

If all works as expected, the command output should look something like this:

> avalanche subnet deploy mySubnet✔ Local NetworkDeploying [mySubnet] to Local NetworkInstalling subnet-evm-v0.4.3...subnet-evm-v0.4.3 installation successfulBackend controller started, pid: 93928, output at: /Users/subnet-developer/.avalanche-cli/runs/server_20221122_173138/avalanche-cli-backendInstalling avalanchego-v1.9.3...avalanchego-v1.9.3 installation successfulVMs ready.Starting network.....................Blockchain has been deployed. Wait until network acknowledges.........Network ready to use. Local network node endpoints:+-------+----------+------------------------------------------------------------------------------------+| NODE  |    VM    |                                        URL                                         |+-------+----------+------------------------------------------------------------------------------------+| node2 | mySubnet | http://127.0.0.1:9652/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpc |+-------+----------+------------------------------------------------------------------------------------+| node3 | mySubnet | http://127.0.0.1:9654/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpc |+-------+----------+------------------------------------------------------------------------------------+| node4 | mySubnet | http://127.0.0.1:9656/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpc |+-------+----------+------------------------------------------------------------------------------------+| node5 | mySubnet | http://127.0.0.1:9658/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpc |+-------+----------+------------------------------------------------------------------------------------+| node1 | mySubnet | http://127.0.0.1:9650/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpc |+-------+----------+------------------------------------------------------------------------------------+Browser Extension connection details (any node URL from above works):RPC URL:          http://127.0.0.1:9650/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpcFunded address:   0x8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC with 1000000 (10^18) - private key: 56289e99c94b6912bfc12adc093c9b51124f0dc54ac7a766b2bc5ccf558d8027Network name:     mySubnetChain ID:         54325Currency Symbol:  TUTORIAL

You can use the deployment details to connect to and interact with your Subnet. Now it’s time to interact with it.

Interacting with Your Subnet​

You can use the value provided by Browser Extension connection details to connect to your Subnet with MetaMask, Core, or any other wallet.

Browser Extension connection details (any node URL from above works):RPC URL:          http://127.0.0.1:9650/ext/bc/SPqou41AALqxDquEycNYuTJmRvZYbfoV9DYApDJVXKXuwVFPz/rpcFunded address:   0x8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC with 1000000 (10^18) - private key: 56289e99c94b6912bfc12adc093c9b51124f0dc54ac7a766b2bc5ccf558d8027Network name:     mySubnetChain ID:         54325Currency Symbol:  TUTORIAL

This tutorial uses MetaMask.

Importing the Test Private Key​

DANGER

This address derives from a well-known private key. Anyone can steal funds sent to this address. Only use it on development networks that only you have access to. If you send production funds to this address, attackers may steal them instantly.

First, you need to import your airdrop private key into MetaMask. Do this by clicking the profile bubble in the top right corner and select Import account.

Import the well-known private key 0x56289e99c94b6912bfc12adc093c9b51124f0dc54ac7a766b2bc5ccf558d8027.

At the bottom of the next page, select Add a network manually. Enter your Subnet’s details, found in the output of your avalanche subnet deploy command, into the form and click Save.

If all worked as expected, your balance should read 1 million tokens. Your Subnet is ready for action. You might want to try to Deploy a Smart Contract on Your Subnet-EVM Using Remix and MetaMask.

Congrats Subnetooooor, you just deployed your first Subnet!