Subnet Creation

A quick review of creating a Subnet on Avalanche - the foundation for our permissioned L1

In the Avalanche Fundamentals course, you learned how to quickly set up an L1 using the Developer Console. This section provides an in depth review of that flow, understanding what comes pre-configured in our genesis, and laying the foundation for what we will need for our Permissioned L1.

Creating a Subnet

Let's create a fresh new Subnet that we can use during this course to test all of the tools and flows for managing Permissioned L1s.

Create Builder Account & Fund Wallet

Before creating your Subnet, we recommend setting up an Avalanche Builder Account for easier access to testnet resources.

Benefits of a Builder Account:

Faucet: C-Chain and P-Chain Testnet AVAX directly sent to your account without needing to claim
Free Managed Testnet Infrastructure: Access free managed testnet nodes and ICM relayers for your L1
No Docker Required: Launch and manage nodes directly from the Builder Console without local setup

After creating your account:

Download Core Wallet if not already installed
Set Core to Testnet mode (upper-right toggle button)
Visit the Builder Console to claim test AVAX on both C-Chain and P-Chain

Create Subnet and Blockchain Records

Create the Subnet by issuing two transactions on the P-Chain (hence the need for test AVAX on the P-chain).

These transactions are:

CreateSubnetTx - Creates a Subnet identified by the transaction hash
CreateChainTx - Adds a blockchain to the Subnet

For this guide, we will create our blockchain as an uncustomized EVM so you just need to rename it (if you want).

On Step 2: Create a Chain select the Genesis JSON tab to the right and skim through it. No need to understand it all but good to get familiar with it before the next section.

Key Parameters:

Subnet Owner: P-chain address of your connected wallet
Chain Name: Your blockchain's name
VM ID: Default value srEX...Dy when creating with an uncustomized VM
Genesis Data: Initial blockchain configuration

Set Up Validator Node

Launch a node to track your Subnet. This node will become a validator for your Subnet, and later will be managed by the Validator Manager contract when we convert to L1.

Use our free managed testnet infrastructure - no Docker installation or AWS account required:

Builder Console

Hosted L1 Testnet Nodes

We recommend using cloud-hosted Avalanche nodes with open ports for testing, as running a node locally can be challenging and may introduce security risks when configuring the required ports. To simplify the process, the Avalanche Builder Hub provides free access to hosted testnet nodes, allowing developers to quickly experiment without managing their own infrastructure. This service is completely free to use, but you'll need to create an Avalanche Builder Account to get started.

Testnet Only Feature

Builder Hub Nodes are only available on testnet. Switch to Fuji testnet to create and manage nodes for your L1s.

Managing Your Nodes

After creating nodes, you can view and manage them at the Testnet Infrastructure Console.

Key Takeaways

P-Chain Registry: All validators and blockchains are registered on the P-Chain
Subnet Foundation: Your Subnet provides the blockchain infrastructure necessary for this course
Managed Infrastructure: Builder Hub provides free managed testnet nodes, eliminating the need for Docker or AWS setup