The first step is to install Rust and dependencies. Refer to the [Lighthouse Book](https://lighthouse-book.sigmaprime.io/installation-source.html#dependencies) for installation. We will also need [jq](https://jqlang.github.io/jq/), which can be installed with `sudo apt install jq`.
Then, we clone the Lighthouse repository:
```bash
cd ~
git clone https://github.com/sigp/lighthouse.git
cd lighthouse
```
We are now ready to build Lighthouse. Run the command:
This will build `lighthouse` and `lcli`. For `geth` and `bootnode`, go to [geth website](https://geth.ethereum.org/downloads) and download the `Geth & Tools`. For example, to download and extract `Geth & Tools 1.13.1`:
The testnet starts a consensus layer and execution layer boot node along with `BN_COUNT`
(the number of beacon nodes) each connected to a geth execution client and `VC_COUNT` (the number of validator clients). By default, `BN_COUNT=4`, `VC_COUNT=4`.
The `start_local_testnet.sh` script takes four options `-v VC_COUNT`, `-d DEBUG_LEVEL`, `-p` to enable builder proposals and `-h` for help. It also takes a mandatory `GENESIS_FILE` for initialising geth's state.
A sample `genesis.json` is provided in this directory.
The `ETH1_BLOCK_HASH` environment variable is set to the block_hash of the genesis execution layer block which depends on the contents of `genesis.json`. Users of these scripts need to ensure that the `ETH1_BLOCK_HASH` variable is updated if genesis file is modified.
where `beacon_node_1` can be changed to `beacon_node_2`, `beacon_node_3` or `beacon_node_4` to view logs for different beacon nodes. The same applies to validator clients and geth nodes.
Once a testnet is stopped, it cannot be continued from where it left off. When the start local testnet command is run, it will start a new local testnet.
In [Starting the testnet](./README.md#starting-the-testnet), the testnet is started automatically with predetermined parameters (database directory, ports used etc). This section describes some modifications of the local testnet settings, e.g., changing the database directory, or changing the ports used.
The testnet also contains parameters that are specified in `vars.env`, such as the slot time `SECONDS_PER_SLOT=3` (instead of 12 seconds on mainnet). You may change these parameters to suit your testing purposes. After that, in the `local_testnet` directory, run the following command to create genesis state with embedded validators and validator keys, and also to update the time in `genesis.json`:
You can create additional geth, beacon node and validator client instances by changing the ports, e.g., for a second geth, beacon node and validator client:
The `BN_COUNT` parameter is used to adjust the division of these generated keys among separate validator client instances.
For e.g. for `VALIDATOR_COUNT=80` and `BN_COUNT=4`, the validator keys are distributed over 4 datadirs with 20 keystores per datadir. The datadirs are located in `$DATADIR/node_{i}` which can be passed to separate validator client
You can delete the current testnet and all related files using the following command. Alternatively, if you wish to start another testnet, doing the steps [Starting the testnet](./README.md#starting-the-testnet) will automatically delete the files and start a fresh local testnet.
2. The above mock builders do not support non-mainnet presets as of now, and will require setting `SECONDS_PER_SLOT` and `SECONDS_PER_ETH1_BLOCK` to `12` in `./vars.env`.
3. Start the testnet with the following command (the `-p` flag enables the validator client `--builder-proposals` flag):
Some addresses in the local testnet are seeded with testnet ETH, allowing users to carry out transactions. To send a transaction, we first add the address to a wallet, such as [Metamask](https://metamask.io/). The private keys for the addresses are listed [here](https://github.com/sigp/lighthouse/blob/441fc1691b69f9edc4bbdc6665f3efab16265c9b/testing/execution_engine_integration/src/execution_engine.rs#L13-L14).
Next, we add the local testnet to Metamask, a brief guide can be found [here](https://support.metamask.io/hc/en-us/articles/360043227612-How-to-add-a-custom-network-RPC). If you start the local testnet with default settings, the network RPC is: http://localhost:6001 and the `Chain ID` is `4242`, as defined in [`vars.env`](https://github.com/sigp/lighthouse/blob/441fc1691b69f9edc4bbdc6665f3efab16265c9b/scripts/local_testnet/vars.env#L42). Once the network and account are added, you should see that the account contains testnet ETH which allow us to carry out transactions.
