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Setting up a Celestia light node ​

This tutorial will guide you through setting up a Celestia light node, which will allow you to perform data availability sampling (DAS) on Celestia's data availability (DA) network.

Overview of light nodes ​

Light nodes ensure data availability. This is the most common way to interact with Celestia networks.

light-node

Light nodes have the following behavior:

  1. They listen for ExtendedHeaders, i.e. wrapped “raw” headers, that notify Celestia nodes of new block headers and relevant DA metadata.
  2. They perform DAS on the received headers

Hardware requirements ​

The following minimum hardware requirements are recommended for running a light node:

  • Memory: 500 MB RAM (minimum)
  • CPU: Single Core
  • Disk: 100 GB SSD Storage
  • Bandwidth: 56 Kbps for Download/56 Kbps for Upload

Setting up your light node ​

This tutorial was performed on an Ubuntu Linux 20.04 (LTS) x64 instance machine.

Set up dependencies on the setting up environment page.

Install celestia-node ​

Install the celestia binary by building and installing celestia-node.

Initialize the light node ​

Run the following command:

sh
celestia light init
celestia light init
sh
celestia light init --p2p.network mocha
celestia light init --p2p.network mocha
sh
celestia light init --p2p.network arabica
celestia light init --p2p.network arabica

The output in your terminal will show the location of your node store and config. It will also show confirmation that the node store has been initialized.

Start the light node ​

Start the light node with a connection to a validator node's gRPC endpoint (which is usually exposed on port 9090):

In order for access to the ability to get and submit state-related information, such as the ability to submit PayForBlobs transactions, or query for the node's account balance, a gRPC endpoint of a validator (core) node must be passed as directed below.

Refer to the ports section of the celestia-node troubleshooting page for information on which ports are required to be open on your machine.

sh
celestia light start --core.ip rpc.celestia.pops.one --p2p.network celestia
celestia light start --core.ip rpc.celestia.pops.one --p2p.network celestia
sh
celestia light start --core.ip rpc-mocha.pops.one --p2p.network mocha
celestia light start --core.ip rpc-mocha.pops.one --p2p.network mocha
sh
celestia light start --core.ip validator-1.celestia-arabica-11.com --p2p.network arabica
celestia light start --core.ip validator-1.celestia-arabica-11.com --p2p.network arabica

Tip: you can replace the core.ip with a consensus node RPC endpoint from mainnet, mocha, or arabica.

Keys and wallets ​

You can create your key for your node by running the following command with the cel-key utility in the celestia-node directory:

sh
./cel-key add <key-name> --keyring-backend test \
    --node.type light --p2p.network <network>
./cel-key add <key-name> --keyring-backend test \
    --node.type light --p2p.network <network>

You can start your light node with the key created above by running the following command:

sh
celestia light start --keyring.keyname my_celes_key \
    --core.ip consensus.lunaroasis.net
celestia light start --keyring.keyname my_celes_key \
    --core.ip consensus.lunaroasis.net
sh
celestia light start --keyring.keyname my_celes_key \
    --core.ip rpc-mocha.pops.one --p2p.network mocha
celestia light start --keyring.keyname my_celes_key \
    --core.ip rpc-mocha.pops.one --p2p.network mocha
sh
celestia light start --keyring.keyname my_celes_key \
    --core.ip validator-1.celestia-arabica-11.com \
    --p2p.network arabica
celestia light start --keyring.keyname my_celes_key \
    --core.ip validator-1.celestia-arabica-11.com \
    --p2p.network arabica

Once you start the light node, a wallet key will be generated for you. You will need to fund that address with testnet tokens to pay for PayForBlob transactions.

You can find the address using the RPC CLI or by running the following command in the celestia-node directory:

sh
./cel-key list --node.type light --keyring-backend test \
    --p2p.network <network>
./cel-key list --node.type light --keyring-backend test \
    --p2p.network <network>

Testnet tokens ​

You have two networks to get testnet tokens from:

You can request funds to your wallet address using the following command in Discord:

console
$request <CELESTIA-ADDRESS>
$request <CELESTIA-ADDRESS>

Where <CELESTIA-ADDRESS> is the celestia1****** address generated when you created the wallet.

Optional: run the light node with a custom key ​

In order to run a light node using a custom key:

  1. The custom key must exist inside the celestia light node directory at the correct path (default: ~/.celestia-light/keys/keyring-test)
  2. The name of the custom key must be passed upon start, like so:
sh
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
sh
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
    --p2p.network arabica
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
    --p2p.network arabica
sh
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
    --p2p.network mocha
celestia light start --core.ip <URI> \
    --keyring.keyname <name-of-custom-key> \
    --p2p.network mocha

Optional: Migrate node id to another server ​

To migrate a light node ID:

  1. You need to back up two files located in the celestia-light node directory at the correct path (default: ~/.celestia-light/keys).
  2. Upload the files to the new server and start the node.

Optional: start light node with SystemD ​

Follow the tutorial on setting up the light node as a background process with SystemD.

Data availability sampling ​

With your light node running, you can check out this tutorial on submitting PayForBlob transactions.