Testnet

Learn how to deploy a local testnet or connect to an existing public one

Pre-requisite Readings

• Install Ethermint
• Install Docker
• Install docker-compose

Single-node, Local, Manual Testnet

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

Initialize node

Copy $MONIKER=testing $KEY=mykey $CHAINID="ethermint-1" ethermintd init $MONIKER --chain-id=$CHAINID

Monikers can contain only ASCII characters. Using Unicode characters will render your node unreachable.

You can edit this moniker later, in the $(HOME)/.ethermintd/config/config.toml file:

Copy # A custom human readable name for this node moniker = "<your_custom_moniker>"

You can edit the $HOME/.ethermintd/config/app.toml file in order to enable the anti spam mechanism and reject incoming transactions with less than the minimum gas prices:

Copy # This is a TOML config file. # For more information, see https://github.com/toml-lang/toml ##### main base config options ##### # The minimum gas prices a validator is willing to accept for processing a # transaction. A transaction's fees must meet the minimum of any denomination # specified in this config (e.g. 10aphoton). minimum-gas-prices = ""

Genesis Procedure

Copy # Create a key to hold your account ethermintcli keys add $KEY # Add that key into the genesis.app_state.accounts array in the genesis file # 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, the default is staking ethermintd add-genesis-account $(ethermintcli keys show validator -a) 1000000000stake,10000000000aphoton # Generate the transaction that creates your validator ethermintd gentx --name $KEY # Add the generated bonding transaction to the genesis file ethermintd collect-gentxs # Finally, check the correctness of the genesis.json file ethermintd validate-genesis

Run Testnet

Now its safe to start the daemon:

Copy ethermintd start

You can then stop the node using Ctrl+C.

Multi-node, Local, Automated Testnet

Build Testnet & Start Testnet

To build start a 4 node testnet run:

Copy make localnet-start

This command creates a 4-node network using the ethermintdnode Docker image. The ports for each node are found in this table:

Node ID	P2P Port	Tendermint RPC Port	REST/ Ethereum JSON-RPC Port	WebSocket Port
ethermintnode0	26656	26657	8545	8546
ethermintnode1	26659	26660	8547	8548
ethermintnode2	26661	26662	8549	8550
ethermintnode3	26663	26664	8551	8552

To update the binary, just rebuild it and restart the nodes

Copy make localnet-start

The command above command will run containers in the background using Docker compose. You will see the network being created:

Copy ... Creating network "chainsafe-ethermint_localnet" with driver "bridge" Creating ethermintdnode0 ... done Creating ethermintdnode2 ... done Creating ethermintdnode1 ... done Creating ethermintdnode3 ... done

Stop Testnet

Once you are done, execute:

Copy make localnet-stop

Configuration

The make localnet-start creates files for a 4-node testnet in ./build by calling the ethermintd testnet command. This outputs a handful of files in the ./build directory:

Copy tree -L 3 build/ build/ ├── ethermintcli ├── ethermintd ├── gentxs │ ├── node0.json │ ├── node1.json │ ├── node2.json │ └── node3.json ├── node0 │ ├── ethermintcli │ │ ├── key_seed.json │ │ └── keyring-test-cosmos │ └── ethermintd │ ├── config │ ├── data │ └── ethermintd.log ├── node1 │ ├── ethermintcli │ │ ├── key_seed.json │ │ └── keyring-test-cosmos │ └── ethermintd │ ├── config │ ├── data │ └── ethermintd.log ├── node2 │ ├── ethermintcli │ │ ├── key_seed.json │ │ └── keyring-test-cosmos │ └── ethermintd │ ├── config │ ├── data │ └── ethermintd.log └── node3 ├── ethermintcli │ ├── key_seed.json │ └── keyring-test-cosmos └── ethermintd ├── config ├── data └── ethermintd.log

Each ./build/nodeN directory is mounted to the /ethermintd directory in each container.

Logging

In order to see the logs of a particular node you can use the following command:

Copy # node 0: daemon logs docker exec ethermintdnode0 tail ethermintd.log # node 0: REST & RPC logs docker exec ethermintdnode0 tail ethermintcli.log

The logs for the daemon will look like:

Copy I[2020-07-29|17:33:52.452] starting ABCI with Tendermint module=main E[2020-07-29|17:33:53.394] Can't add peer's address to addrbook module=p2p err="Cannot add non-routable address 272a247b837653cf068d39efd4c407ffbd9a0e6f@192.168.10.5:26656" E[2020-07-29|17:33:53.394] Can't add peer's address to addrbook module=p2p err="Cannot add non-routable address 3e05d3637b7ebf4fc0948bbef01b54d670aa810a@192.168.10.4:26656" E[2020-07-29|17:33:53.394] Can't add peer's address to addrbook module=p2p err="Cannot add non-routable address 689f8606ede0b26ad5b79ae244c14cc67ab4efe7@192.168.10.3:26656" I[2020-07-29|17:33:58.828] Executed block module=state height=88 validTxs=0 invalidTxs=0 I[2020-07-29|17:33:58.830] Committed state module=state height=88 txs=0 appHash=90CC5FA53CF8B5EC49653A14DA20888AD81C92FCF646F04D501453FD89FCC791 I[2020-07-29|17:34:04.032] Executed block module=state height=89 validTxs=0 invalidTxs=0 I[2020-07-29|17:34:04.034] Committed state module=state height=89 txs=0 appHash=0B54C4DB1A0DACB1EEDCD662B221C048C826D309FD2A2F31FF26BAE8D2D7D8D7 I[2020-07-29|17:34:09.381] Executed block module=state height=90 validTxs=0 invalidTxs=0 I[2020-07-29|17:34:09.383] Committed state module=state height=90 txs=0 appHash=75FD1EE834F0669D5E717C812F36B21D5F20B3CCBB45E8B8D415CB9C4513DE51 I[2020-07-29|17:34:14.700] Executed block module=state height=91 validTxs=0 invalidTxs=0

You can disregard the Can't add peer's address to addrbook warning. As long as the blocks are being produced and the app hashes are the same for each node, there should not be any issues.

Whereas the logs for the REST & RPC server would look like:

Copy I[2020-07-30|09:39:17.488] Starting application REST service (chain-id: "7305661614933169792")... module=rest-server I[2020-07-30|09:39:17.488] Starting RPC HTTP server on 127.0.0.1:8545 module=rest-server ...

Follow Logs

You can also watch logs as they are produced via Docker with the --follow (-f) flag, for example:

Copy docker logs -f ethermintdnode0

Interact With the Testnet

Ethereum JSON RPC & Websocket Ports

To interact with the testnet via WebSockets or RPC/API, you will send your request to the corresponding ports:

Eth JSON-RPC	Eth WS
8545	8546

You can send a curl command such as:

Copy curl -X POST --data '{"jsonrpc":"2.0","method":"eth_accounts","params":[],"id":1}' -H "Content-Type: application/json" 192.162.10.1:8545

The IP address will be the public IP of the docker container.

Additional instructions on how to interact with the WebSocket can be found on the events documentation.

Keys & Accounts

To interact with ethermintcli and start querying state or creating txs, you use the ethermintcli directory of any given node as your home, for example:

Copy ethermintcli keys list --home ./build/node0/ethermintcli

Now that accounts exists, you may create new accounts and send those accounts funds!

Note: Each node's seed is located at ./build/nodeN/ethermintcli/key_seed.json and can be restored to the CLI using the ethermintcli keys add --restore command

Special Binaries

If you have multiple binaries with different names, you can specify which one to run with the BINARY environment variable. The path of the binary is relative to the attached volume. For example:

Copy # Run with custom binary BINARY=ethermint make localnet-start

Multi-node, Public, Manual Testnet

If you are looking to connect to a persistent public testnet. You will need to manually configure your node.

Genesis and Seeds

Copy the Genesis File

If you want to start a network from scratch, you will need to start the genesis procedure by creating a genesis.json and submit + collect the genesis transactions from the validators.

If you want to connect to an existing testnet, fetch the testnet's genesis.json file and copy it into the ethermintd's config directory (i.e $HOME/.ethermintd/config/genesis.json).

Then verify the correctness of the genesis configuration file:

Copy ethermintd validate-genesis

Add Seed Nodes

Your node needs to know how to find peers. You'll need to add healthy seed nodes to $HOME/.ethermintd/config/config.toml. If those seeds aren't working, you can find more seeds and persistent peers on an existing explorer.

For more information on seeds and peers, you can the Tendermint P2P documentation.

Start testnet

The final step is to start the nodes. Once enough voting power (+2/3) from the genesis validators is up-and-running, the testnet will start producing blocks.

Next

Learn about how to setup a validator node on Ethermint