Run Relayers

Steps to set up your own Snowbridge message relayers.

1. Setup

2. Upgrade

1. Setup

1.1 AWS account

The first thing you will need is an AWS account. Register if you do not have an account yet.

1.2 Clone infra repo

Clone the infrastructure repository:

git clone https://github.com/Snowfork/snowbridge-relayers-infra.git

1.3 Install Ansible & dependencies

Install Ansible and its dependencies:

brew install pipx
pipx install --include-deps ansible boto3 botocore
pipx ensurepath
ansible-galaxy collection install amazon.aws

1.4 Create AWS key pair

On the AWS console, under the EC2 section, create an ED25519 key pair called snowbridge-relayers-key.

1.5 Set AWS env variables

In the snowbridge-relayers-infra directory, create a .envrc file with the following values:

export AWS_ACCESS_KEY_ID=
export AWS_SECRET_ACCESS_KEY=
export AWS_ACCOUNT_ID=
export AWS_DEFAULT_REGION=eu-central-1

Add your AWS access key ID, secret access key and account ID.

1.6 Create EC2 instance

Run command from inside the snowbridge-relayers-infra directory:

ansible-playbook -i inventory/message-relayers/aws_ec2.yml infra.yml

It will create an EC2 instance to run the relayers on.

1.7 Add secrets

Add the following plaintext secrets to AWS secrets manager:

snowbridge/dwellir-eth-node-api-key
snowbridge/dwellir-polkadot-node-api-key
snowbridge/chainalysis-api-key
snowbridge/asset-hub-ethereum-relay
snowbridge/asset-hub-parachain-relay

Example of how to add an AWS secret.

1.7.1 Lodestar, Polkadot Nodes & Chainalysis key

Ask for API keys for dwellir-eth-node-api-key, dwellir-polkadot-node-api-key and chainalysis-api-key in Snowbridge Relayer Telegram group: https://t.me/+I8Iel-Eaxcw3NjU0 (keys will be DM'ed to you).

1.7.2 Ethereum relay key

The asset-hub-ethereum-relay is a private key for an prefunded account on Polkadot BridgeHub. To retrieve the private key from an account on Polkadot with seedphrase "cat cow milk...", use subkey:

./target/release/subkey inspect "cat cow milk..."

Use the secret seed hash as the snowbridge/asset-hub-ethereum-relay secret.

1.7.3 Parachain relayer key

The asset-hub-parachain-relay is a private key for a funded account on Ethereum.

1.8 Fund relayer accounts

The Ethereum and Polkadot BridgeHub account should be funded with $10 each, at least.

1.9 Set relayer number

Once you have set up all of the above, ask for a relayer ID and relayer count in Snowbridge Relayer Telegram group: https://t.me/+I8Iel-Eaxcw3NjU0. Add the key and ID in your .envrc file. Example .envrc file.

1.10 Install Relayers

Once you have added all the secrets, you can deploy your relayers:

ssh-agent bash
ssh-add /path/to/snowbridge-relayers-key.pem
ansible-playbook -i inventory/message-relayers/aws_ec2.yml relayers.yml

Once it has completed, ssh into your instance.

ssh -i message-relayers-key.pem [email protected]

Check that you see no relayer errors for each relayer:

sudo journalctl -fu snowbridge-asset-hub-ethereum-relay --since today
sudo journalctl -fu snowbridge-asset-hub-parachain-relay --since today

1.11 Increment Relayer count

Once the relayer has started up successfully, all relaying parties should increment their relayer count config and redeploy their relayer config. This action will be prompted in the TG group.

1.12 Monitoring

To set up monitoring, register an account with PagerDuty.

Once registered, create a new service: Services -> Services Directory. Click on New. Call the service "Snowbridge Message Relayers"

Under service "Snowbridge Message Relayers", click on Integrations. Add a new Amazon Cloudwatch integration. Copy the integration URL.

In your snowbridge-relayers-infra project, copy the URL to your .envrc file:

export PAGER_URL=https://events.eu.pagerduty.com/integration/xxx/enqueue

Now run the Ansible script to create all the necessary metrics, alarms, topic and subscription on AWS:

git pull
ssh-agent bash
ssh-add /path/to/snowbridge-relayers-key.pem
ansible-playbook -i inventory/message-relayers/aws_ec2.yml alarm.yml

Test the alarms by trigging a failure condition (i.e. change the URL of one of the service endpoints to an invalid value).

2. Upgrade

To upgrade the relayer, run the following commands:

git pull
ssh-agent bash
ssh-add /path/to/snowbridge-relayers-key.pem
ansible-playbook -i inventory/message-relayers/aws_ec2.yml relayers.yml --start-at "Upload binary"