Polkadot Omni Node

This is a white labeled implementation based on polkadot-omni-node-lib. It can be used to start a parachain node from a provided chain spec file. It is only compatible with runtimes that use block number u32 and Aura consensus.

Installation

Download & expose it via PATH:

# Download and set it on PATH.
wget https://github.com/paritytech/polkadot-sdk/releases/download/<stable_release_tag>/polkadot-omni-node
chmod +x polkadot-omni-node
export PATH="$PATH:`pwd`"

Replace <stable_release_tag> with the latest stable tag from the Polkadot SDK releases

For example:

wget https://github.com/paritytech/polkadot-sdk/releases/download/polkadot-stable2506-1/polkadot-omni-node

Compile & install via cargo:

# Assuming ~/.cargo/bin is on the PATH
cargo install polkadot-omni-node --locked

Usage

A basic example for an Omni Node run starts from a runtime which implements the sp_genesis_builder::GenesisBuilder. The interface mandates the runtime to expose a named-preset.

1. Install chain-spec-builder

Note: chain-spec-builder binary is published on crates.io under staging-chain-spec-builder due to a name conflict. Install it with cargo like bellow :

cargo install staging-chain-spec-builder --locked

2. Generate a chain spec

Omni Node requires the chain spec to include a JSON key named relay_chain. It is set to a chain id, representing the chain name, e.g. westend, paseo, rococo, polkadot, or kusama, but there are also local variants that can be used for testing, like rococo-local or westend-local. The local variants are available only for a build of polkadot-omni-node with westend-native and rococo-native features respectively.

Additionaly, the --para-id flag can be used to set the JSON key named para_id. This flag is used by nodes to determine the parachain id, and it is especially useful when the parachain id can not be fetched from the runtime, when the state points to a runtime that does not implement the cumulus_primitives_core::GetParachainInfo runtime API. It is recommended for runtimes to implement the runtime API and be upgraded on chain.

Example command bellow:

chain-spec-builder create --relay-chain <relay_chain_id> --para-id <id> -r <runtime.wasm> named-preset <preset_name>

3. Run Omni Node

And now with the generated chain spec we can start the node in development mode like so:

polkadot-omni-node --dev --chain <chain_spec.json>

Useful links

• Omni Node Polkadot SDK Docs
• Chain Spec Genesis Reference Docs
• polkadot-parachain-bin
• polkadot-sdk-parachain-template
• frame-omni-bencher
• staging-chain-spec-builder