lighthouse/book/src/simple-testnet.md

Simple Local Testnet

With a functional development environment, starting a local multi-node testnet is easy:

1. Start the first node: $ lighthouse bn testnet -f recent 8
2. Start a validator client: $ lighthouse bn testnet -b insecure 0 8
3. Start more nodes with $ lighthouse bn -b 10 testnet -f bootstrap http://localhost:5052
   • Increment the -b value by 10 for each additional node.

Detailed Instructions

First, setup a Lighthouse development environment and navigate to the target/release directory (this is where the binaries are located).

Starting a beacon node

Start a new node (creating a fresh database and configuration in $HOME/.lighthouse), using:

$ lighthouse bn testnet -f recent 8

Notes:

• The -f flag ignores any existing database or configuration, backing them up before re-initializing.
• 8 is number of validators with deposits in the genesis state.
• See $ lighthouse bn testnet recent --help for more configuration options, including minimal/mainnet specification.

Starting a validator client

In a new terminal window, start the validator client with:

$ lighthouse vc testnet -b insecure 0 8

Notes:

• The -b flag means the validator client will "bootstrap" specs and config from the beacon node.
• The insecure command uses predictable, well-known private keys. Since this is just a local testnet, these are fine.
• The 0 8 indicates that this validator client should manage 8 validators, starting at validator 0 (the first deposited validator).
• The validator client will try to connect to the beacon node at localhost. See --help to configure that address and other features.

Adding another beacon node

You may connect another (non-validating) node to your local network using the lighthouse bootstrap command.

In a new terminal window, run:

$ lighthouse bn -b 10 testnet -r bootstrap

Notes:

• The -b (or --port-bump) increases all the listening TCP/UDP ports of the new node to 10 higher. Your first node's HTTP server was at TCP 5052 but this one will be at 5062.
• The -r flag creates a new data directory with a random string appended (avoids data directory collisions between nodes).
• The default bootstrap HTTP address is http://localhost:5052. The new node will download configuration via HTTP before starting sync via libp2p.
• See $ lighthouse bn testnet bootstrap --help for more configuration.