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Run the Full Node

When setting up a full node and joining a blockchain network, there are typically two main states that a node needs to synchronize with the network: Block Sync and State Sync. In this guide we will cover State Sync, which is the preferable approach.

State Sync​

State Sync is the process of downloading the current state of the blockchain. When a Full Node joins a network, it needs to download the current state of the blockchain. The current state includes all account balances, contract code, and contract storage. State sync is a more efficient way to get up to speed with the current state of the network, as it only downloads the necessary information rather than downloading the entire blockchain.

State Sync is used to perform the following tasks that we will see in detail:

  • Bootstrap a node
  • Free up space on your hard disk

Bootstrap The Node​

To bootstrap your node with state sync, follow the steps below.

Create the file state-sync.sh

sudo nano state-sync.sh

Add the following code in it (to add your own or favourite RPC check this list here):

state-sync.sh

#!/bin/bash

SNAP_RPC="https://rpc.sentinel.co:443"
SNAP_RPC2="https://rpc-sentinel.whispernode.com:443"

LATEST_HEIGHT=$(curl -s $SNAP_RPC/block | jq -r .result.block.header.height); \
BLOCK_HEIGHT=$((LATEST_HEIGHT - 1000)); \
TRUST_HASH=$(curl -s "$SNAP_RPC/block?height=$BLOCK_HEIGHT" | jq -r .result.block_id.hash)

sed -i.bak -E "s|^(enable[[:space:]]+=[[:space:]]+).*$|\1true| ; \
s|^(rpc_servers[[:space:]]+=[[:space:]]+).*$|\1\"$SNAP_RPC,$SNAP_RPC2\"| ; \
s|^(trust_height[[:space:]]+=[[:space:]]+).*$|\1$BLOCK_HEIGHT| ; \
s|^(trust_hash[[:space:]]+=[[:space:]]+).*$|\1\"$TRUST_HASH\"|" $HOME/.sentinelhub/config/config.toml

This script ensures that the new synchronization process starts from a point slightly before the absolute latest block. This provides a margin of safety and avoid potential synchronization issues that might occur due to due network delays or other factors.

Make the file executable

chmod +x state-sync.sh

Launch the script

./state-sync.sh

Start the node by running the following command:

sudo systemctl start sentinelhub.service

Your node will fully synchronize within 10 minutes. Periodically check its status using the following command:

curl --silent "http://localhost:26657/status" | jq -S

If the value of result.sync_info.catching_up is false, it indicates that the node is synchronized and ready to start signing blocks.

To monitor the logs in real-time, use the following command:

sudo journalctl -u sentinelhub.service -f --output=cat

Free up space​

This step should be performed regularly, as the hard disk tends to fill up over time. It is advisable to establish a monitoring structure to determine when it is necessary to free up space.

To get started, edit the state-sync.sh file and and include the final three lines

state-sync.sh

#!/bin/bash

SNAP_RPC="https://rpc.sentinel.co:443"
SNAP_RPC2="https://rpc-sentinel.whispernode.com:443"

LATEST_HEIGHT=$(curl -s $SNAP_RPC/block | jq -r .result.block.header.height); \
BLOCK_HEIGHT=$((LATEST_HEIGHT - 1000)); \
TRUST_HASH=$(curl -s "$SNAP_RPC/block?height=$BLOCK_HEIGHT" | jq -r .result.block_id.hash)

sed -i.bak -E "s|^(enable[[:space:]]+=[[:space:]]+).*$|\1true| ; \
s|^(rpc_servers[[:space:]]+=[[:space:]]+).*$|\1\"$SNAP_RPC,$SNAP_RPC2\"| ; \
s|^(trust_height[[:space:]]+=[[:space:]]+).*$|\1$BLOCK_HEIGHT| ; \
s|^(trust_hash[[:space:]]+=[[:space:]]+).*$|\1\"$TRUST_HASH\"|" $HOME/.sentinelhub/config/config.toml

mv $HOME/.sentinelhub/data $HOME/.sentinelhub/data-old
mkdir -p $HOME/.sentinelhub/data
cp $HOME/.sentinelhub/data-old/priv_validator_state.json $HOME/.sentinelhub/data

Stop the node

sudo systemctl stop sentinelhub.service

Launch the script

./state-sync.sh

Start the node by running the following command:

sudo systemctl start sentinelhub.service

Your node will fully synchronize within 10 minutes. Periodically check its status using the following command:

curl --silent "http://localhost:26657/status" | jq -S

If the value of result.sync_info.catching_up is false, it indicates that the node is synchronized and ready to start signing blocks.

To monitor the logs in real-time, use the following command:

sudo journalctl -u sentinelhub.service -f --output=cat

Once your node has completed synchronization, you can confidently proceed to delete the .sentinel/data-old/ folder.

sudo rm -fr $HOME/.sentinelhub/data-old/