Author: jsun

In the previous post I described the process of setting up a headless Raspberry Pi 4 (8GB) with remote VNC desktop access. It includes 1GB SDD drive, which is needed to run bitcoin full node with full archive of blockchain transactions.

In this post I will describe the process I used to set up a powerful multi-purpose Bitcoin node for the cryptocurrency community, that includes the following elements.

• Bitcoin core – the default and standard bitcoin full node software that started the whole thing
• ElectrumX server – de-centralized cryptocurrency wallet server. Wallet software needs it to make payments/transfers etc.
• Lighnting Network Daemon (LND) – Level 2 network built on top of bitcoin to facilitate fast and cheap small amount payments.

Install and Run Bitcoin Core

• Install Tor network for more privacy, sudo apt install tor
• Download the pre-built Bitcoin Core binary for ARM Linux 64bit, untar it, and copy over to /user/local.

wget https://bitcoin.org/bin/bitcoin-core-0.21.0/bitcoin-0.21.0-aarch64-linux-gnu.tar.gz
tar xzf bitcoin-0.21.0-aarch64-linux-gnu.tar.gz
sudo cp -a bitcoin-0.21.0/* /usr/local/

• Run bitcoin-qt -txindex and start populating the blockchain data. It will take 2+ days and will consume >350GB in disk space!
  • DON’T SELECT “prune” MODE! Otherwise Electrum server won’t work.

• Configure bitcoin for hardening and interactions with ElectrumX/LND
  • Create ~/.bitcoin/bitcoin.conf file. See sample setup below.
  • In this setup, we don’t listen to incoming peers over IPv4/IPv6 for enhanced privacy. New transactions will be broadcasted to Tor network only.
  • I also disabled wallet feature for better privacy again.
  • zmq (ZeroMQ) is needed for LND connection.

# index all transactions; LND/ElectrumX needs it
txindex=1

# bitcoin-qt accept RPC or not; needed for EPS/ElectrumX
server=1

# EPS needs wallet feature; electrumx does not
disablewallet=1

# don't broadcast transactions from our own wallet; will submit through Tor
# only useful when disablewallet==0
walletbroadcast=0

# # Maximum number of inbound+outbound connections. default 125
maxconnections=32

# enable electrumx server and LND
rpcuser=YOUR_RPC_USER
rpcpassword=YOUR_RPC_PASSWORD

# Listening for peers, enabled by default except when 'connect' is being used
# we don't export bitcoin ports or accept any incoming connections,
# because we would expose our own transactions to peers associated with our IP
# We only connect outgoing through tor
listen=0

# outgoing traffic use onion/tor only (default any)
proxy=127.0.0.1:9050
onlynet=onion

# debug logging - values: 0, 1, net, ....
debug=0

# needed by LND; I don't understand
zmqpubrawblock=tcp://127.0.0.1:28332
zmqpubrawtx=tcp://127.0.0.1:28333

Install ElectrumX Server

• Install dependencies

sudo apt install -y python3-pip libleveldb-dev
sudo pip3 install aiohttp aiorpc
sudo pip3 install pylru
sudo pip3 install plyvel

• Clone the the repo and install into /usr/local.
  • Note there are 2 primary electrumx repos on github.com. Make sure choose “spesmilo” one. The other one, albeit older, stopped supporting bitcoin due to recent segwit address introduction.

git clone https://github.com/spesmilo/electrumx.git
cd ~/electrumx
sudo python3 setup.py install

• Add user to ssl-cert group to access the private SSL key

sudo usermod -a -G ssl-cert $USER

• If bitcoin core has finished initial data sync, you can start ElectrumX server with the following script. Make sure you forward port 50001 and 50002 to the Raspberry Pi 4.

#!/bin/bash

# REQUIRED env variables
export DB_DIRECTORY=$HOME/.electrumx/db
export COIN=Bitcoin
DAEMON_URL="http://YOUR_RPC_USER:YOUR_RPC_PASSWORD@localhost:8332"

# Optional env variables
export PUBLIC_IP=$(curl -s http://whatismyip.akamai.com/)
export SERVICES=rpc://localhost:8000,tcp://:50001,ssl://:50002
export REPORT_SERVICES=ssl://$PUBLIC_IP:50002
export SSL_CERTFILE=/etc/ssl/certs/ssl-cert-snakeoil.pem
export SSL_KEYFILE=/etc/ssl/private/ssl-cert-snakeoil.key

# replace with your wallet address!
export DONATION_ADDRESS="bc1q52we5s8qyddhvrfscjn4qyn5nvq8hf92k9rt2w"

# log all sent transactions
electrumx_server

Install LND

Lightning Network in some sense is more complex than bitcoin. You are strongly suggested to review some basic concepts before setting up the software. There are multiple LN server implementations. LND is a popular one.

• Install the pre-built binary image for ARM64

wget https://github.com/lightningnetwork/lnd/releases/download/v0.12.0-beta.rc6/lnd-linux-arm64-v0.12.0-beta.rc6.tar.gz
tar xzf lnd-linux-arm64-v0.12.0-beta.rc6.tar.gz
sudo cp lnd-linux-arm64-v0.12.0-beta.rc6/* /usr/local/bin

• Set up config file

mkdir ~/.lnd
wget -O ~/.lnd/lnd.conf https://raw.githubusercontent.com/lightningnetwork/lnd/master/sample-lnd.conf

• Below is a sample setup based on my own node

listen=0.0.0.0:9735
nolisten=false
rpclisten=0.0.0.0:10009
externalip=xxx.xxx.xxx.xxx
alias=YourFavoriateNameForThisNode
[Bitcoin]
bitcoin.active=true
bitcoin.mainnet=true
bitcoin.node=bitcoind
bitcoin.basefee=1
bitcoin.feerate=1
[Bitcoind]
bitcoind.dir=~/.bitcoin
bitcoind.rpcuser=YOUR_RPC_USER
bitcoind.rpcpass=YOUR_RPC_PASSWORD
bitcoind.zmqpubrawblock=tcp://127.0.0.1:28332
bitcoind.zmqpubrawtx=tcp://127.0.0.1:28333
bitcoind.estimatemode=ECONOMICAL

• Run LND with “lnd” command
  • First time run, you will need to create a wallet, lncli create
  • For later running, you will need to unlock wallet, lncli unlock
    • If you like to automate LND startup, you will likely need lncli unlock --stdin option to pass in the wallet password via a script.

• (Optional) if you like to set up a public LND node so that others can reach you, enable port forward on port 9735. You need to be a public node to participate in LN routing.

(Optional) Install RTL

RTL stands for “Ride The Lightning”, which provides a web interface to visually interact with LND. Otherwise you can just the commandline interface, which can be a little boring (and hard)

• Install package and dependencies

git clone https://github.com/Ride-The-Lightning/RTL.git
cd RTL/
sudo apt install nodejs
sudo apt install npm
npm install --only=prod
cp sample-RTL-Config.json RTL-Config.json
vi RTL-Config.json
node rtl.js 

• In order to run “node rtl.js” successfully, you need to configure RTL-config.json properly. Below is the sample setup derived from my own node.

{
  "multiPass": "YOUR_RTL_PASSWORD",
  "port": "3000",
  "defaultNodeIndex": 1,
  "SSO": {
    "rtlSSO": 0,
    "rtlCookiePath": "",
    "logoutRedirectLink": ""
  },
  "nodes": [
    {
      "index": 1,
      "lnNode": "Node 1",
      "lnImplementation": "LND",
      "Authentication": {
        "macaroonPath": "/home/ubuntu/.lnd/data/chain/bitcoin/mainnet/",
        "configPath": "/home/ubuntu/.lnd/lnd.conf",
        "swapMacaroonPath": ""
      },
      "Settings": {
        "userPersona": "MERCHANT",
        "themeMode": "DAY",
        "themeColor": "PURPLE",
        "channelBackupPath": "/home/ubuntu/.lnd/backup",
        "enableLogging": false,
        "lnServerUrl": "https://localhost:8080",
        "swapServerUrl": "https://localhost:8081",
        "fiatConversion": false
      }
    }
  ],
}

• Once RTL starts running, you can open a browser and point at Raspberry Pi 4 IP address at port 3000. You see stats and perform actions with LND.

How You May Benefit

• Use your own ElectrumX server for increased trust and privacy.
  • In this guide, we disable bitcoin core listening from public IP addresses. All new transactions are broadcasted from Tor. That increases privacy and anonymity.
• You set up donation wallet address in ElectrumX. It seems people do donate, although not that common.
• Once you set up LND properly, you can collect routing fees.

Show Your Support

This post is only complete if I can show you how I set up the donation and LN connection. 🙂 And your reading is only complete when you perform one of the following actions. 😛

For donation, Bitcoin wallet address is “bc1qyc48kmpweyx2kpqhq8n6r0ckr2fqsfvz2qxpx4”

For Lightning Network, my node public key is “0362a4372375bd24c5b8f8bb2ea85ae2ccf783808477e68cfb06121694b34d1927”

Appendix A – Reference Links on Lightning Network

• Good over all guide, https://stadicus.github.io/RaspiBolt/
• RTL github, https://github.com/Ride-The-Lightning/RTL
• Raspiblitz, populary but code seems pretty crappy, https://github.com/rootzoll/raspiblitz
• Good intro and TODO on lightning network, https://decrypt.co/resources/bitcoin-lightning-network
• LND github page, https://github.com/lightningnetwork/lnd
• A good source of LN https://lightning.engineering/blog
• LND setup ; https://blog.lightning.engineering/posts/2019/08/15/routing-quide-1.html
• LND operation guide :
  • https://medium.com/@suheb__/how-to-ride-the-lightning-447af999dcd2

Appendix B – How to create inbound liquidity for lightning network

• Free ones
  • https://lightningto.me/
  • https://lnbig.com/#/open-channel
• Paid ones
  • https://yalls.org/about/
  • https://www.bitrefill.com/thor-lightning-network-channels/?hl=en
  • https://lightningpowerusers.com/home/
• Tips
  • https://gist.github.com/bretton/53bc511b6fdafef31951199dd25bbf88