# Single Node

# Pre-requisite Readings

# Automated Localnet (script)

You can customize the local testnet script by changing values for convenience for example:

Copy # customize the name of your key, the chain-id, moniker of the node, keyring backend, and log level KEY="dev0" CHAINID="evmos_9000-4" MONIKER="localtestnet" KEYRING="test" LOGLEVEL="info" # Allocate genesis accounts (cosmos formatted addresses) evmosd add-genesis-account $KEY 100000000000000000000000000aevmos --keyring-backend $KEYRING # Sign genesis transaction evmosd gentx $KEY 1000000000000000000000aevmos --keyring-backend $KEYRING --chain-id $CHAINID

The default configuration will generate a single validator localnet with the chain-id evmosd-1 and one predefined account (dev0) with some allocated funds at the genesis.

You can start the local chain using:

Copy $ local_node.sh ...

To avoid overwriting any data for a real node used in production, it was decided to store the automatically generated testing configuration at ~/.tmp-evmosd instead of the default ~/.evmosd.

When working with the local_node.sh script, it is necessary to extend all evmosd commands, that target the local test node, with the --home ~/.tmp-evmosd flag. This is mandatory, because the home directory cannot be stored in the evmosd configuration, which can be seen in the output below. For ease of use, it might be sensible to export this directory path as an environment variable:

Copy $ export TMP=$HOME/.tmp-evmosd` $ evmosd config --home $TMP { "chain-id": "evmos_9000-1", "keyring-backend": "test", "output": "text", "node": "tcp://localhost:26657", "broadcast-mode": "sync" }

# Manual Localnet

This guide helps you create a single validator node that runs a network locally for testing and other development related uses.

# Initialize the chain

Before actually running the node, we need to initialize the chain, and most importantly its genesis file. This is done with the init subcommand:

Copy $MONIKER=testing $KEY=dev0 $CHAINID="evmos_9000-4" # The argument $MONIKER is the custom username of your node, it should be human-readable. evmosd init $MONIKER --chain-id=$CHAINID

You can edit this moniker later by updating the config.toml file.

The command above creates all the configuration files needed for your node and validator to run, as well as a default genesis file, which defines the initial state of the network. All these configuration files are in ~/.evmosd by default, but you can overwrite the location of this folder by passing the --home flag.

# Genesis Procedure

# Adding Genesis Accounts

Before starting the chain, you need to populate the state with at least one account using the keyring:

Copy evmosd keys add my_validator

Once you have created a local account, go ahead and grant it some aevmos tokens in your chain's genesis file. Doing so will also make sure your chain is aware of this account's existence:

Copy evmosd add-genesis-account my_validator 10000000000aevmos

Now that your account has some tokens, you need to add a validator to your chain.

For this guide, you will add your local node (created via the init command above) as a validator of your chain. Validators can be declared before a chain is first started via a special transaction included in the genesis file called a gentx:

Copy # Create a gentx # NOTE: this command lets you set the number of coins. # Make sure this account has some coins with the genesis.app_state.staking.params.bond_denom denom evmosd add-genesis-account my_validator 1000000000stake,10000000000aevmos

A gentx does three things:

  1. Registers the validator account you created as a validator operator account (i.e. the account that controls the validator).
  2. Self-delegates the provided amount of staking tokens.
  3. Link the operator account with a Tendermint node pubkey that will be used for signing blocks. If no --pubkey flag is provided, it defaults to the local node pubkey created via the evmosd init command above.

For more information on gentx, use the following command:

Copy evmosd gentx --help

# Collecting gentx

By default, the genesis file do not contain any gentxs. A gentx is a transaction that bonds staking token present in the genesis file under accounts to a validator, essentially creating a validator at genesis. The chain will start as soon as more than 2/3rds of the validators (weighted by voting power) that are the recipient of a valid gentx come online after genesis_time.

A gentx can be added manually to the genesis file, or via the following command:

Copy # Add the gentx to the genesis file evmosd collect-gentxs

This command will add all the gentxs stored in ~/.evmosd/config/gentx to the genesis file.

# Run Testnet

Finally, check the correctness of the genesis.json file:

Copy evmosd validate-genesis

Now that everything is set up, you can finally start your node:

Copy evmosd start

To check all the available customizable options when running the node, use the --help flag.

You should see blocks come in.

The previous command allow you to run a single node. This is enough for the next section on interacting with this node, but you may wish to run multiple nodes at the same time, and see how consensus happens between them.

You can then stop the node using Ctrl+C.