Polkadot Secure Validator Setup

This repo describes a potential setup for a Polkadot validator that aims to prevent some types of potential attacks at the TCP layer and below. The Workflow section describes the Platform Layer and the Application Layer in more detail.

Usage

There are two ways of using this repository:

• Platform & Application Layer

  Configure credentials for infrastructure providers such as AWS, Azure, GCP and/or Packet, then execute the Terraform process to automatically deploy the required machines (Platform Layer) and setup the Application Layer.

  See the Complete Guide for more.

• Application Layer

  Setup Debian-based machines yourself, which only need basic SSH access and configure those in an inventory. The Ansible scripts will setup the entire Application Layer.

  See the Ansible Guide for more.

Structure

The secure validator setup is composed of one or more validators that run with a local instance of NGINX as a reverse TCP proxy in front of them. The validators are instructed to:

• advertise themselves with the public IP of the node and the port where the reverse proxy is listening.
• bind to the localhost interface, so that they only allow incoming connections from the proxy.

The setup also configures a firewall in which the default p2p port is closed for incoming connections and only the proxy port is open.

Workflow

The secure validator setup is structured in two layers, an underlying platform and the applications that run on top of it.

Platform Layer

Validators are created using the terraform modules located at terraform directory. We have created code for several providers but it is possible to add new ones, please reach out if you are interested in any provider currently not available.

Besides the actual machines the terraform modules create the minimum required networking infrastructure for adding firewall rules to protect the nodes.

Application Layer

This is done through the ansible playbook and polkadot-validator role located at ansible, basically the role performs these actions:

• Software firewall setup, for the validator we only allow the proxy, SSH and, if enabled, node-exporter ports.
• Configure journald to tune log storage.
• Create polkadot user and group.
• Configure NGINX proxy
• Setup polkadot service, including binary download.
• Polkadot session management, create session keys if they are not present.
• Setup node-exporter if the configuration includes it.

Note about upgrades from the sentries setup

The current version of polkadot-secure-validator doesn't allow to create and configure sentry nodes. Although the terraform files and ansible roles of this latest version can be applied on setups created with previous versions, the validators would be configured to work without sentries and to connect to the network using the local reverse proxy instead.

If you created the sentries with a previous version of this tool through terraform following the complete workflow, then they will not be deleted automatically when running this new version. In short, the old sentries will no longer be used by the validators and it will be up to you to remove them manually.