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Subnet Creation

In this section, we will learn how to use the ash.avalanche.subnet role to create a Subnet with an EVM Subnet, and add validator nodes to the Subnet.

note

For this tutorial, we will use the local inventory provided by the Ansible Avalanche Getting Started repository. See Create a Local Test Network for details.

tip

Always make sure you have the latest version of the collection installed. See Installation and upgrade.

Configure the Subnet​

All the transactions related to the Subnet creation will be issued from the subnet_txs_host node of the Ansible inventory. Thus, we configure the Subnet in inventories/local/group_vars/subnet_txs_host.yml.

Configure the blockchains​

The ash.avalanche.subnet role allows to configure the blockchains that will be created in the Subnet with the subnet_blockchains_list variable. You can edit the blockchains parameters, e.g. its name:

inventories/local/group_vars/subnet_txs_host.yml
subnet_blockchains_list:
  - name: AshLocalEVM
    vm: subnet-evm
    genesis_data:
      config:
        chainId: 66666
        homesteadBlock: 0
        eip150Block: 0
        [...]

Configure the validators list​

There are 2 ways to add validators to the Subnet:

With the subnet_validators Ansible group​

info

You need to have SSH access to the nodes to use this method.

Add validators to the subnet_validators group in the inventory. This is the most convenient way because the validators' node IDs are automatically resolved on each host (in the ash.avalanche.node.add-validator playbook).

In the local inventory, the subnet_validators group is already configured with all the nodes:

inventories/local/hosts
[subnet_validators]
validator0[1:5]

With the subnet_validators_params variable​

Add validators to the subnet_validators_params variable. This is especially useful:

  • To include third-party nodes to which you don't have SSH access
  • To customize validations parameters for each validator (e.g. the start and end times, the weight, etc.)

For this tutorial, we will not use this method but we configured the first validator as an example:

inventories/local/group_vars/subnet_txs_host.yml
subnet_validators_params:
  - node_id: NodeID-7Xhw2mDxuDS44j42TCB6U5579esbSt3Lg
    start_time: "{{ subnet_validator_start_time }}"
    end_time: "{{ subnet_validator_end_time }}"
    stake_or_weight: 100
    delegation_fee: 2

Configure the Subnet transactions wallet​

info

The wallet P-Chain address will be used as the Subnet control key.

Creating Subnets, blockchains and adding validators requires using a wallet to pay for transaction fees. The private key of the wallet is configured with the subnet_txs_private_key variable:

inventories/local/group_vars/subnet_txs_host.yml
# Private key of the pre-funded account
subnet_txs_private_key: PrivateKey-ewoqjP7PxY4yr3iLTpLisriqt94hdyDFNgchSxGGztUrTXtNN
subnet_txs_key_encoding: cb58

You can use another wallet by changing the subnet_txs_private_key variable. See Wallet funding for more information on how to create and fund a wallet using the Ash CLI.

Extra configuration​

Extra configuration is possible for the Subnet, e.g. the validation start and end times, the validator weight, etc. For a list of all available variables, see the ash.avalanche.subnet role reference.

Create the Subnet​

Run the ash.avalanche.create_subnet playbook to create the Subnet, blockchains and add validators:

ansible-playbook ash.avalanche.create_subnet -i inventories/local

At the end of the Subnet creation, information about the new Subnet is displayed:

ok: [validator01] =>
  msg: |-
    The Subnet has been created with its blockchains, and the validators added.
    Make sure to add the Subnet ID to the `avalanchego_track_subnets` list of each validator.
    Subnet ID = p4jUwqZsA2LuSftroCd3zb4ytH8W99oXKuKVZdsty7eQ3rXD6
info

This playbook calls

  1. The ash.avalanche.subnet role to create the Subnet, the blockchains and add the validators from the subnet_validators_list variable
  2. The ash.avalanche.node.add-validator playbook to add the validators from the subnet_validators group

Track the Subnet with the validators​

The ash.avalanche.subnet role does not handle Subnet tracking on validator nodes. The list of tracked Subnets is handled by the avalanchego_track_subnets variable in the ash.avalanche.node role.

To track the Subnet on our nodes:

  1. Add the Subnet ID to the avalanchego_track_subnets variable. For this tutorial, this variable is in avalanche_nodes.yml:

    inventories/local/group_vars/avalanche_nodes.yml
    avalanchego_track_subnets:
      - p4jUwqZsA2LuSftroCd3zb4ytH8W99oXKuKVZdsty7eQ3rXD6

  2. Run the ash.avalanche.provision_nodes to apply the new configuration and restart the :

    ansible-playbook ash.avalanche.provision_nodes -i inventories/local

Check the Subnet validators​

After 2 minutes, we can check the validators list of the Subnet:

note

If not already done, configure the Ash CLI for local Avalanche network by following Configure the Ash CLI for your network.

Command
multipass exec validator01 -- ash avalanche subnet info p4jUwqZsA2LuSftroCd3zb4ytH8W99oXKuKVZdsty7eQ3rXD6
Output
Subnet 'p4jUwqZsA2LuSftroCd3zb4ytH8W99oXKuKVZdsty7eQ3rXD6':
  Type: Permissioned
  Control keys: ["P-local18jma8ppw3nhx5r4ap8clazz0dps7rv5u00z96u"]
  Threshold:    1
  Blockchains list (1):
  - AshLocalEVM:
    ID:      2dEmExGjJT6MouJRr1PqV4PSQEbScDAjKuPtT6pgqYR5xdUuac
    VM ID:   srEXiWaHuhNyGwPUi444Tu47ZEDwxTWrbQiuD7FmgSAQ6X7Dy
    VM type: SubnetEVM
  Validators list (5):
  - NodeID-7Xhw2mDxuDS44j42TCB6U5579esbSt3Lg
  - NodeID-MFrZFVCXPv5iCn6M9K6XduxGTYp891xXZ
  - NodeID-NFBbbJ4qCmNaCzeW7sxErhvWqvEQMnYcN
  - NodeID-GWPcbFJZFfZreETSoWjPimr846mXEKCtu
  - NodeID-P7oB2McjBGgW2NXXWVYjV8JEDFoW9xDE5
tip

You can use the --extended flag to get more information about the validators, notably their weight and the start/end time of their validation period.

Connect to the Subnet and start issuing transactions​

The Subnet is now ready to be used! You can connect any EVM-compatible wallet (e.g. MetaMask, Core, Frame, etc.) to it and start issuing transactions, deploying smart contracts, etc.

Use the following settings to connect to the Subnet:

Network name: AshLocalEVM
New RPC URL: http://${VALIDATOR01_IP}:9650/ext/bc/${BLOCKCHAIN_ID}/rpc
Chain ID: 66666
Symbol: ASH
Explorer URL: http://${FRONTEND_IP}:4000

To get the public IP addresses of the nodes, you can use the following command:

# For VALIDATOR01
terraform -chdir=terraform/multipass output -json validators_ips | jq '.[0]'
# For FRONTEND
terraform -chdir=terraform/multipass output frontend_ip

To get the blockchain ID, you can use the following command:

multipass exec validator01 -- ash avalanche subnet info "$SUBNET_ID" -j | jq '.blockchains[0].id'
note

See the Subnet Blockchain Explorer tutorial to install the block explorer!