Run a Pruned Bitcoin Node

This guide is written for a Unix based system. It's reasonable to expect some modifications will be required for other operating systems.

When started, the pruned Bitcoin node will take roughly ~24 hours to reach chain tip.

While bitcoin is syncing, it's recommended to keep a stacks-blockchain node at chain tip, or use a stacks chainstate archive.

Requirements:

• Bitcoin Core >= v25.0

  • https://github.com/bitcoin/bitcoin

  • https://bitcoincore.org/en/download/

• Host with a minimum of:

  • 2 vCPU (a single dedicated cpu for the bitcoind process)

  • 4GB Memory (during sync, more available memory will improve sync time)

  • 50GB free disk space (actual usage is closer to 20GB)

• User account: bitcoin:bitcoin

• Chainstate directory located at: /bitcoin/mainnet

  • bitcoin user must have read/write access.

• Config directory located at: /etc/bitcoin

  • bitcoin user must have at least read access

Caveats

BIP-0159

In short, this BIP specifies that pruned nodes will advertise the service bit NODE_NETWORK_LIMITED, which restricts syncing blocks older than 288 blocks (~2 days).

What this means is that in practice, a stacks-blockchain node:

• Cannot sync from genesis using a pruned node.

• Must not be offline or otherwise down for longer than ~2 days (or 288 Bitcoin blocks).

1

Add bitcoin user and set file ownership

$ sudo mkdir -p /bitcoin/mainnet
$ sudo mkdir /etc/bitcoin
$ sudo useradd bitcoin -d /bitcoin
$ sudo chown -R bitcoin:bitcoin /bitcoin /etc/bitcoin/

2

Bitcoin Config

Below is a sample config used to sync a pruned bitcoin node - feel free to adjust as needed.

If using the systemd unit below, save this file as /etc/bitcoin/bitcoin.conf

Notes:

• btuser:btcpass is hardcoded as an rpcauth user/password (generated using this script).

• Only localhost access is allowed (127.0.0.1) on the standard mainnet ports.

• Pruning is set to be small, storing only the last 1GB of blocks (for p2p traffic, this is more than enough).

• dbcache is set to the maximum of 16GB.

• Wallet (and wallet rpc calls) are disabled.

## [rpc]

# Accept command line and JSON-RPC commands.
server=1

# Allow JSON-RPC connections from specified source.
rpcallowip=127.0.0.1/0

# Bind to given address to listen for JSON-RPC connections.
rpcbind=127.0.0.1:8332

# Username and HMAC-SHA-256 hashed password for JSON-RPC connections.

#   Use the script at https://github.com/bitcoin/bitcoin/tree/master/share/rpcauth to generate

#   Note: may be specified multiple times for different users.
rpcauth=btcuser:18857b4df4b1f0f5e6b1d7884617ab39$de6e02e1da8ee138ee702e13e0637e24679d844756216b066c3aeac4bcac5e10 # btuser:btcpass

# Optional: rpcwhitelist can restrict listed RPC calls to specific rpcauth users.

#   Uncomment the below the restrict the `limited` user to a small subset of `get` commands

# rpcauth=limited:350c91a60895b567c4662c27e63e9a41$25188b0f51f2f974dcdc75c1e0d41174e8f7ae19fb96927abf68ac5bc1e8897b # limited:limited

# rpcwhitelist=limited:getblockchaininfo,getblock,getblockcount,getblockhash,getblockheader,getnetworkinfo

# rpcwhitelistdefault=0

## [core]

# Specify data directory
datadir=/bitcoin/mainnet

# Do not keep transactions in the mempool longer than <n> hours (default: 336)
mempoolexpiry=24

# Bind to given address and always listen on it (default: 0.0.0.0)
bind=127.0.0.1:8333

# Maximum database cache size <n> MiB (4 to 16384, default: 450). In addition, unused mempool memory is shared for this cache
dbcache=16384

# Maintain a full transaction index, used by the getrawtransaction rpc call (**Running a pruned node requires that this option is disabled**)
txindex=0

# Reduce storage requirements by enabling pruning (deleting) of old

# blocks. This allows the pruneblockchain RPC to be called to

# delete specific blocks and enables automatic pruning of old

# blocks if a target size in MiB is provided. This mode is

# incompatible with -txindex. Warning: Reverting this setting

# requires re-downloading the entire blockchain. (default: 0 =

# disable pruning blocks, 1 = allow manual pruning via RPC, >=550 =

# automatically prune block files to stay under the specified

# target size in MiB)
prune=1024 # 1GB of chainstate is enough for p2p block data (if using the RPC,this can be adjusted higher to store more blocks)

## [wallet]

# Do not load the wallet and disable wallet RPC calls
disablewallet=1

3

Systemd unit file

ref: https://github.com/bitcoin/bitcoin/blob/master/contrib/init/bitcoind.service

[Unit]
Description=Bitcoin daemon
Documentation=https://github.com/bitcoin/bitcoin/blob/master/doc/init.md

# https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/
After=network-online.target
Wants=network-online.target

[Service]
ExecStart=/usr/bin/bitcoind -pid=/run/bitcoind/bitcoind.pid \
                            -conf=/etc/bitcoin/bitcoin.conf \
                            -startupnotify='systemd-notify --ready' \
                            -shutdownnotify='systemd-notify --stopping'

# Make sure the config directory is readable by the service user
PermissionsStartOnly=true
ExecStartPre=/bin/chgrp bitcoin /etc/bitcoin

# Process management
####################

Type=notify
NotifyAccess=all
PIDFile=/run/bitcoind/bitcoind.pid

Restart=on-failure
TimeoutStartSec=infinity
TimeoutStopSec=600

# Directory creation and permissions
####################################

# Run as bitcoin:bitcoin
User=bitcoin
Group=bitcoin

# /run/bitcoind
RuntimeDirectory=bitcoind
RuntimeDirectoryMode=0710

# /etc/bitcoin
ConfigurationDirectory=bitcoin
ConfigurationDirectoryMode=0710

# /var/lib/bitcoind
StateDirectory=bitcoind
StateDirectoryMode=0710

# Hardening measures
####################

# Provide a private /tmp and /var/tmp.
PrivateTmp=true

# Mount /usr, /boot/ and /etc read-only for the process.
ProtectSystem=full

# Deny access to /home, /root and /run/user
ProtectHome=true

# Disallow the process and all of its children to gain

# new privileges through execve().
NoNewPrivileges=true

# Use a new /dev namespace only populated with API pseudo devices

# such as /dev/null, /dev/zero and /dev/random.
PrivateDevices=true

# Deny the creation of writable and executable memory mappings.
MemoryDenyWriteExecute=true

# Restrict ABIs to help ensure MemoryDenyWriteExecute is enforced
SystemCallArchitectures=native

[Install]
WantedBy=multi-user.target

4

Enable and start the Bitcoin service

$ sudo systemctl daemon-reload
$ sudo systemctl enable bitcoin.service
$ sudo systemctl start bitcoin.service

5

Track sync progress

Once started, you may track the sync progress:

$ sudo tail -f /bitcoin/mainnet/debug.log
2024-12-05T19:35:31Z UpdateTip: new best=00000000000000000058990a84cc8f8eab25dbbd572f123f9190cea7256d7349 height=509258 version=0x20000000 log2_work=88.128280 tx=299522737 date='2018-02-15T03:42:14Z' progress=0.295203 cache=43.5MiB(172740txo)
...
$ bitcoin-cli \
    -rpcconnect=127.0.0.1 \
    -rpcport=8332 \
    -rpcuser=btcuser \
    -rpcpassword=btcpass \
    getblockcount
509016