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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 on the data availability (DA) network.

To view a video tutorial for setting up a Celestia light node, click here

Overview of light nodes​

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

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 data availability sampling (DAS) on the received headers

Hardware requirements​

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

  • Memory: 2 GB RAM
  • CPU: Single Core
  • Disk: 5 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.

Setup the dependencies​

First, make sure to update and upgrade the OS:

sudo apt update && sudo apt upgrade -y

These are essential packages that are necessary to execute many tasks like downloading files, compiling, and monitoring the node:

sudo apt install curl tar wget clang pkg-config libssl-dev jq build-essential git make ncdu -y

Install Golang​

Celestia-app and celestia-node are written in Golang so we must install Golang to build and run them.

ver="1.19.1" 
cd $HOME 
wget "https://golang.org/dl/go$ver.linux-amd64.tar.gz" 
sudo rm -rf /usr/local/go 
sudo tar -C /usr/local -xzf "go$ver.linux-amd64.tar.gz" 
rm "go$ver.linux-amd64.tar.gz"

Now we need to add the /usr/local/go/bin directory to $PATH:

echo "export PATH=$PATH:/usr/local/go/bin:$HOME/go/bin" >> $HOME/.bash_profile
source $HOME/.bash_profile

To check if Go was installed correctly run:

go version

The output should be the version installed:

go version go1.19.1 linux/amd64

Install celestia-node​

Installing celestia-node for the blockspacerace testnet means installing a specific version to be compatible with the network.

Install the celestia-node binary by running the following commands:

cd $HOME 
rm -rf celestia-node 
git clone https://github.com/celestiaorg/celestia-node.git 
cd celestia-node/ 
git checkout tags/v0.7.2 
make build 
make install 
make cel-key

Verify that the binary is working and check the version with the celestia version command:

$ celestia version 
Semantic version: v0.7.2 
Commit: eea18a72891af318fb26abb7264416b679ec2a16 
Build Date: Thu Dec 15 10:19:22 PM UTC 2022 
System version: amd64/linux 
Golang version: go1.19.1

Initialize the light node​

Run the following command:

celestia light init --p2p.network blockspacerace

You should see output like:

$ celestia light init
2022-12-19T21:45:24.591Z        INFO    node    nodebuilder/init.go:19  Initializing Light Node Store over '/root/.celestia-light-blockspacerace'
2022-12-19T21:45:24.591Z        INFO    node    nodebuilder/init.go:50  Saving config   {"path": "/root/.celestia-light-blockspacerace/config.toml"}
2022-12-19T21:45:24.592Z        INFO    node    nodebuilder/init.go:51  Node Store 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):

NOTE: In order for access to the ability to get/submit state-related information, such as the ability to submit PayForBlob transactions, or query for the node's account balance, a gRPC endpoint of a validator (core) node must be passed as directed below. For gateway, the default IP Address is localhost and the default port is 26659.

celestia light start --core.ip <ip-address> --gateway --gateway.addr <ip-address> --gateway.port <port> --p2p.network <network>

For ports:

NOTE: The --core.ip gRPC port defaults to 9090, so if you do not specify it in the command line, it will default to that port. You can add the port after the IP address or use the --core.grpc.port flag to specify another port if you prefer.

If you need a list of RPC endpoints to connect to, you can check from the list here

For example, your command might look something like this:

celestia light start --core.ip <ip-address> --gateway --gateway.addr <ip-address> --gateway.port <port> --p2p.network blockspacerace

Keys and wallets​

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

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

For arabica, if you are on 0.6.1, make sure to use --p2p.network arabica when generating your keys.

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

celestia light start --core.ip <ip-address> --keyring.accname <key_name> --gateway --gateway.addr <ip-address> --gateway.port <port> --p2p.network blockspacerace

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 by running the following command in the celestia-node directory:

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

You have three networks to get testnet tokens from:

NOTE: If you are running a light node for your sovereign rollup, it is highly recommended to request Arabica devnet tokens as Arabica has the latest changes that can be used to test for developing your sovereign rollup. You can still use Mocha Testnet as well, it is just used for Validator operations.

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

$request <Wallet-Address>

Where <Wallet-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:
celestia light start --core.ip <ip-address> --keyring.accname <name_of_custom_key> --gateway --gateway.addr <ip-address> --gateway.port <port> --p2p.network blockspacerace

Optional: start light node with SystemD​

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

Data availability sampling (DAS)​

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