Installation

Step 1: Node Installation

Step 1.1: Node Configuration

This step provides procedures to install BandChain's executable and sync blocks with other peers.

Assuming to run on Ubuntu 22.04 LTS allowing connection on port 26656 for P2P connection.

Before beginning instructions, the following variables should be set to be used in further instructions. Please make sure that these variables are set every time when using the new shell session.

# Chain ID of testnet
export CHAIN_ID="band-laozi-testnet6"
# Wallet name to be used as validator's account, please change this into your name (no whitespace).
export WALLET_NAME=<YOUR_WALLET_NAME>
# Name of your validator node, please change this into your name.
export MONIKER=<YOUR_MONIKER>
# Seed and persistent peers for P2P communication
export SEEDS="da61931cbbbb2b62dbe7c470d049126cf365d257@35.213.165.61:26656,fffd730672f04d5dc065fa9afce2eb1d6bc4d150@35.212.60.28:26656"
# URL of genesis file for Laozi testnet
export GENESIS_FILE_URL=https://raw.githubusercontent.com/bandprotocol/launch/master/band-laozi-testnet6/genesis.json
# Data sources/oracle scripts files
export BIN_FILES_URL=https://raw.githubusercontent.com/bandprotocol/launch/master/band-laozi-testnet6/files.tar.gz
# Faucet endpoint
export FAUCET_URL=https://laozi-testnet6.bandchain.org/faucet

Step 1.2: Build BandChain Core

The following applications are required to build and run the BandChain node.

• make, gcc, g++ (can be obtained from the build-essential package on linux)
• wget, curl for downloading files

# install required tools
sudo apt-get update && \
sudo apt-get upgrade -y && \
sudo apt-get install -y build-essential curl wget jq

• Install Go 1.19.1

# Install Go 1.19.1
wget https://go.dev/dl/go1.19.1.linux-amd64.tar.gz
tar xf go1.19.1.linux-amd64.tar.gz
sudo mv go /usr/local/go

# Set Go path to $PATH variable
echo "export PATH=$PATH:/usr/local/go/bin:~/go/bin" >> $HOME/.profile
source ~/.profile

Go binary should be at /usr/local/go/bin and any executable compiled by go install command should be at ~/go/bin

Step 1.3: Clone & Install BandChain Laozi

cd ~
# Clone BandChain Laozi version v2.5.4
git clone https://github.com/bandprotocol/chain
cd chain
git fetch && git checkout v2.5.4

# Install binaries to $GOPATH/bin
make install

Step 1.4: Initialize the BandChain and download the genesis file

cd $HOME

# Initialize configuration and genesis state
bandd init --chain-id $CHAIN_ID "$MONIKER"

# Replace genesis file with our genesis file
wget $GENESIS_FILE_URL -O $HOME/.band/config/genesis.json

# Download data sources / oracle scripts files, and store in $HOME/.band/files
wget -qO- $BIN_FILES_URL | tar xvz -C $HOME/.band/

# Create new account
bandd keys add $WALLET_NAME

Step 1.5: Setup seeds and minimum gas price

# Add seeds to config.toml
sed -E -i \
  "s/seeds = \".*\"/seeds = \"${SEEDS}\"/" \
  $HOME/.band/config/config.toml

# Add minimum gas price
sed -E -i \
  "s/^minimum-gas-prices *=.*/minimum-gas-prices = \"0.0025uband\"/" \
  $HOME/.band/config/app.toml

Step 2: Setup Cosmovisor

Pre-Requisite Readings

• Cosmoviser

Cosmovisor is a small process manager for Cosmos SDK application binaries that monitors the governance module via stdout for incoming chain upgrade proposals

Step 2.1: Setup environment variables

Add required environment variables for Cosmovisor into your profile

cd ~
echo "export DAEMON_NAME=bandd" >> ~/.profile
echo "export DAEMON_HOME=$HOME/.band" >> ~/.profile
source ~/.profile

Step 2.2: Install and provide binaries

Install Cosmovisor and provide bandd binary to Cosmovisor

# Install Cosmovisor
go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@v1.0.0

# Setup folder and provide bandd binary for Cosmovisor Genesis
mkdir -p $HOME/.band/cosmovisor/genesis/bin
mkdir -p $HOME/.band/cosmovisor/upgrades
cp $HOME/go/bin/bandd $HOME/.band/cosmovisor/genesis/bin

# Setup folder and provide bandd binary for Cosmovisor Upgrades
mkdir -p $HOME/.band/cosmovisor/upgrades/v2_5/bin
cp $HOME/go/bin/bandd $DAEMON_HOME/cosmovisor/upgrades/v2_5/bin

Step 3: Sync with the network

There are two main ways to sync a node on the BandChain; Blocksync and State Sync. However, we recommend using State Sync as it's faster.

Block Sync

Block Sync

Blocksync is faster than traditional consensus and syncs the chain from genesis by downloading blocks and verifying against the Merkle tree of validators. For more information see Tendermint's Fastsync Docs

When syncing via Blocksync, node operators will need to provide the binary of each upgrade version for Cosmovisor to switch when it reaches the upgrade heights.

You can see the detail of genesis and each upgrade in the table below.

Upgrade name	Upgrade Height	Upgrade detail	Go version	Bandd version	Binary path
genesis	0	-	1.16.7	v2.3.6	~/.band/cosmovisor/genesis/bin
v2_4	427000	link	1.19.1	v2.4.1	~/.band/cosmovisor/upgrades/v2_4/bin
v2_5	5557800	link	1.19.1	v2.5.4	~/.band/cosmovisor/upgrades/v2_5/bin

Before doing the next step, you have to build and provide each correct bandd binary version to Cosmovisor in the binary path so that Cosmovisor can automatically switch it correctly.

State Sync

State Sync

State Sync is an efficient and fast way to bootstrap a new node, and it works by replaying larger chunks of application state directly rather than replaying individual blocks or consensus rounds. For more information, see Tendermint's State Sync docs.

Setup variables

# Get trust height and trust hash

LATEST_HEIGHT=$(curl -s https://rpc.laozi-testnet6.bandchain.org/block | jq -r .result.block.header.height);
TRUST_HEIGHT=$(($LATEST_HEIGHT-45000))
TRUST_HASH=$(curl -s "https://rpc.laozi-testnet6.bandchain.org/block?height=$TRUST_HEIGHT" | jq -r .result.block_id.hash)

# show trust height and trust hash
echo "TRUST HEIGHT: $TRUST_HEIGHT"
echo "TRUST HASH: $TRUST_HASH"

Setup State Sync config

# Enable State Sync
sed -i \
    '/\[statesync\]/,+34 s/enable = false/enable = true/' \
    $HOME/.band/config/config.toml

# Set RPC Endpoint for State Sync
sed -E -i \
    "/\[statesync\]/,+34 s/rpc_servers = \".*\"/rpc_servers = \"https\:\/\/rpc.laozi-testnet6.bandchain.org\:443,https\:\/\/rpc.laozi-testnet6.bandchain.org\:443\"/" \
    $HOME/.band/config/config.toml

# Set Trust Height for State Sync
sed -i \
    "/\[statesync\]/,+34 s/trust_height = .*/trust_height = ${TRUST_HEIGHT}/" \
    $HOME/.band/config/config.toml

# Set Trust Hash for State Sync
sed -i \
    "/\[statesync\]/,+34 s/trust_hash = \".*\"/trust_hash = \"${TRUST_HASH}\"/" \
    $HOME/.band/config/config.toml

Step 4: Setup daemon service

We do recommend running the Bandchain node as a daemon, which can be set up using systemctl.

Step 4.1: Create BandChain service

Run the following command to create a new daemon for cosmovisor that runs bandd (This script work on non-root user).

# Write bandd service file to /etc/systemd/system/bandd.service
export USERNAME=$(whoami)
sudo -E bash -c 'cat << EOF > /etc/systemd/system/bandd.service
[Unit]
Description=BandChain Node Daemon
After=network-online.target

[Service]
Environment="DAEMON_NAME=bandd"
Environment="DAEMON_HOME=${HOME}/.band"
Environment="DAEMON_RESTART_AFTER_UPGRADE=true"
Environment="DAEMON_ALLOW_DOWNLOAD_BINARIES=false"
Environment="UNSAFE_SKIP_BACKUP=true"
User=$USERNAME
ExecStart=${HOME}/go/bin/cosmovisor start
Restart=always
RestartSec=3
LimitNOFILE=4096

[Install]
WantedBy=multi-user.target
EOF'

Step 4.2: Register and start bandd service

In this step, we will register and start bandd service

# Register bandd to systemctl
sudo systemctl enable bandd
# Start bandd daemon
sudo systemctl start bandd

Once bandd service has been started, logs can be queried by running journalctl -u bandd.service -f command. You will see your node beginning to sync.

Step 5: Setup Yoda

Pre-requisite Readings

• Yoda

Since a subset of validators who are selected for a data request must send the data they received as a transaction of MsgReportData to BandChain.

Yoda is a program used by BandChain's validator nodes to help automatically query data from data providers by executing data source script, then submitting the result to fulfill the request. Read more on the Yoda section.

Yoda requires indexer to run properly. Please make sure if your node has set indexer in config.toml file as "kv"

Step 5.1: Installation

Before setting up Yoda, the Lambda function executor need to be set up to execute data sources. If this step has not been done yet, please follow the instructions on the following pages (select either one of these methods):

• AWS Lambda Function
• Google Cloud Function

To check Yoda version, use the following command.

yoda version
# v2.5.4

Step 5.2: Set the Yoda configurations

Use the command below to config your Yoda, replacing $VARIABLES with their actual values.

rm -rf ~/.yoda # clear old config if exist
yoda config chain-id $CHAIN_ID
yoda config node http://localhost:26657
yoda config broadcast-timeout "5m"
yoda config rpc-poll-interval "1s"
yoda config max-try 5
yoda config validator $(bandd keys show $WALLET_NAME -a --bech val)

Then, add multiple reporter accounts to allow Yoda to submit transactions concurrently.

yoda keys add REPORTER_1
yoda keys add REPORTER_2
yoda keys add REPORTER_3
yoda keys add REPORTER_4
yoda keys add REPORTER_5

Lastly, configure the Lambda Executor endpoint to helps running data source scripts and return results to Yoda. More details about the executor can be found in this section.

export EXECUTOR_URL=<YOUR_EXECUTOR_URL>
yoda config executor "rest:${EXECUTOR_URL}?timeout=10s"

Step 5.3: Start Yoda

To start Yoda, it's also recommended to use systemctl.

# Write yoda service to /etc/systemd/system/yoda.service
export USERNAME=$(whoami)
sudo -E bash -c 'cat << EOF > /etc/systemd/system/yoda.service
[Unit]
Description=Yoda Daemon
After=network-online.target

[Service]
User=$USERNAME
ExecStart=/home/$USERNAME/go/bin/yoda run
Restart=always
RestartSec=3
LimitNOFILE=4096

[Install]
WantedBy=multi-user.target
EOF'

The first time running Yoda, you will need to register and start yoda services by running the following commands.

# Register yoda to systemctl
sudo systemctl enable yoda
# Start yoda daemon
sudo systemctl start yoda

After yoda service has been started, logs can be queried by running journalctl -u yoda.service -f command. The log should be similar to the following log example below. Once verified, you can stop tailing the log by typing Control-C.

... systemd[...]: Started Yoda Daemon.
... yoda[...]: I[...] ⭐  Creating HTTP client with node URI: tcp://localhost:26657
... yoda[...]: I[...] 🚀  Starting WebSocket subscriber
... yoda[...]: I[...] 👂  Subscribing to events with query: tm.event = 'Tx'...

Step 5.4: Wait for the latest blocks to be synced

It is imperative to exercise caution and allow adequate time for the newly started BandChain node to synchronize its blocks until it has reached the latest block. The latest block can be verified on CosmoScan.