Skip to main content

run a relayer via hermes

A relayer communicates with 2 networks in order for packets (msgs) to be sent between them sercurely & with finality.

GUIDE​

Instructions for setting up a relayer via hermes.

Goals​

  • install hermes relayer
  • configure hermes to networks you would like to use
  • configure keys for hermes to sign msgs with
  • configure & troubleshoot channels, clients, and connections
  • set up software to continuously run

Step 1: Install Hermes​

Option 1 - Install Via Cargo​

first, install rust on your machine if not already installed:

# install rust 
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

*reload your PATH environment variable to include* Cargo's bin directory $HOME/.cargo/bin:

source $HOME/.cargo/env

now, to install they relayer software:

# install the latest release of Hermes
cargo install ibc-relayer-cli --bin hermes --locked

to verify the installation:

hermes version
# output should be: hermes v...

Step 2: Setup Initial Configuration for Hermes​

For each network you would like to relay messages between, you will need to customize the config.toml file the relayer software will use to determine where to listen for packets to communicate between networks.

create a template config file:

hermes config auto --output $HOME/.hermes/config.toml --chain terpnetwork secretnetwork

you should have now created a config.toml file that we can further modify for our needs. Running cat $HOME/.hermes/config.toml should return the default template from the chains you intend to relay packets for

Step 3: Configure Your Relayer Keys​

Your relayer will need to sign & broadcast messages on chain, so first the private keys that we will grant to the relayer must be set up.Generally it is ideal to utilize a fresh wallet and private key, not associated with any personal or critical keys in your possession.

Cosmos blockchains enable various methods for handling how the messages are signed, for example a fee grant for a key a relayer is using, by a completely different key, and ONLY for the messages that are used when relayed packets are received is possible.

To add keys, this example uses a mnemonic-file, which contains just the mnemonic seed phrase of the account you want the relayer to sign & broadcast messages with:

FILE_NAME=$HOME/.hermes/key-1.txt
echo "<just-your-mnemonic-seed>" > "$FILE_NAME"

then, add by restoring the key:

hermes keys add --key-name key-1 --chain 90u-4 --mnemonic-file $HOME/.hermes/key-1.txt

repeat this process for the chains you intend to relay packets for.

Step 4: A Quick Overview of Relayer Channels, Clients, and Connections​

you can find a basic IBC overview to refresh your memory on how IBC on Terp Network is implemented.

Step 5: Spinning Up A Fresh Channel, Client & Connection​

if there is no existing channels between the pair of networks:


Step 6: Setup Continuous Relay Service​

setup a systemd file for your server:

[Unit]
Description=Hermes Service
After=network.target

[Service]
User=<username>
ExecStart=/usr/local/bin/hermes start
Restart=always

[Install]
WantedBy=multi-user.target

Step 7: Monitering IBC Relaying on Terp Network​

A comprehensive guide for monitoring your relayer can be found here.

Sources: