nix-bitcoin/docs/services.md

Nodeinfo

Run nodeinfo to see onion addresses and local addresses for enabled services.

Managing services

NixOS uses the systemd service manager.

Usage:

# Show service status
systemctl status bitcoind

# Show the last 100 log messages
journalctl -u bitcoind -n 100
# Show all log messages since the last system boot
journalctl -b -u bitcoind

# These commands require root permissions
systemctl stop bitcoind
systemctl start bitcoind
systemctl restart bitcoind

# Show the service definition
systemctl cat bitcoind
# Show all service parameters
systemctl show bitcoind

clightning database replication

The clightning database can be replicated to a local path or to a remote SSH target.
When remote replication is enabled, nix-bitcoin mounts a SSHFS to a local path.
Optionally, backups can be encrypted via gocryptfs.

Note: You should also backup the static file hsm_secret (located at /var/lib/clightning/bitcoin/hsm_secret by default), either manually or via the services.backups module.

Remote target via SSHFS

1. Add this to your configuration.nix:

   services.clightning.replication = {
     enable = true;
     sshfs.destination = "user@hostname:directory";
     # This is optional
     encrypt = true;
   };
   programs.ssh.knownHosts."hostname".publicKey = "<ssh public key from running `ssh-keyscan` on the host>";
   

   Leave out the encrypt line if you want to store data on your destination in plaintext.
   Adjust user, hostname and directory as necessary.

2. Deploy

3. To allow SSH access from the nix-bitcoin node to the target node, either use the remote node config below, or copy the contents of $secretsDir/clightning-replication-ssh.pub to the authorized_keys file of user (or use ssh-copy-id).

4. You can restrict the nix-bitcoin node's capabilities on the SSHFS target using OpenSSH's builtin features, as detailed here.

   To implement this on NixOS, add the following to the NixOS configuration of the SSHFS target node:

   systemd.tmpfiles.rules = [
     # Because this directory is chrooted by sshd, it must only be writable by user/group root
     "d /var/backup/nb-replication 0755 root root - -"
     "d /var/backup/nb-replication/writable 0700 nb-replication - - -"
   ];
   
   services.openssh = {
     extraConfig = ''
       Match user nb-replication
         ChrootDirectory /var/backup/nb-replication
         AllowTcpForwarding no
         AllowAgentForwarding no
         ForceCommand internal-sftp
         PasswordAuthentication no
         X11Forwarding no
     '';
   };
   
   users.users.nb-replication = {
     isSystemUser = true;
     group = "nb-replication";
     shell = "${pkgs.coreutils}/bin/false";
     openssh.authorizedKeys.keys = [ "<contents of $secretsDir/clightning-replication-ssh.pub>" ];
   };
   users.groups.nb-replication = {};
   

   With this setup, the corresponding sshfs.destination on the nix-bitcoin node is "nb-replication@hostname:writable".

Local directory target

1. Add this to your configuration.nix

   services.clightning.replication = {
     enable = true;
     local.directory = "/var/backup/clightning";
     encrypt = true;
   };
   

   Leave out the encrypt line if you want to store data in local.directory in plaintext.

2. Deploy

clightning will now replicate database files to local.directory. This can be used to replicate to an external HDD by mounting it at path local.directory.

Custom remote destination

Follow the steps in section "Local directory target" above and mount a custom remote destination (e.g., a NFS or SMB share) to local.directory.
You might want to disable local.setupDirectory in order to create the mount directory yourself with custom permissions.

Connect to RTL

Normally you would connect to RTL via SSH tunneling with a command like this

ssh -L 3000:localhost:3000 root@bitcoin-node

Or like this, if you are using netns-isolation

ssh -L 3000:169.254.1.29:3000 root@bitcoin-node

Otherwise, you can access it via Tor Browser at http://<onion-address>. You can find the <onion-address> with command nodeinfo. The default password location is $secretsDir/rtl-password. See: Secrets dir

Use Zeus (mobile lightning wallet) via Tor

1. Install Zeus

2. Edit your configuration.nix

   For lnd

   Add the following config:

   services.lnd.lndconnect = {
     enable = true;
     onion = true;
   };
   

   For clightning

   Add the following config:

   services.clightning-rest = {
     enable = true;
     lndconnect = {
       enable = true;
       onion = true;
     };
   };
   

3. Deploy your configuration

4. Run the following command on your node (as user operator) to create a QR code with address and authentication information:

   For lnd

   lndconnect
   

   For clightning

   lndconnect-clightning
   

5. Configure Zeus

   • Add a new node
   • Select Scan lndconnect config (at the bottom) and scan the QR code
   • For clightning: Set Node interface to c-lightning-REST
   • Click Save node config
   • Start sending and stacking sats privately

Additional lndconnect features

• Create plain text URLs or QR code images

  lndconnect --url
  lndconnect --image
  

• Set a custom host. By default, lndconnect detects the system's external IP and uses it as the host.

  lndconnect --host myhost
  

Connect to spark-wallet

Requirements

• Android phone
• Orbot installed from F-Droid (recommended) or Google Play
• Spark-wallet installed from direct download or Google Play

1. Enable spark-wallet in configuration.nix

   Change

   # services.spark-wallet.enable = true;
   

   to

   services.spark-wallet.enable = true;
   

2. Deploy new configuration.nix

3. Enable Orbot VPN for spark-wallet

   Open Orbot app
   Turn on "VPN Mode"
   Select Gear icon under "Tor-Enabled Apps"
   Toggle checkbox under Spark icon
   

4. Get the onion address, access key and QR access code for the spark wallet android app

   journalctl -eu spark-wallet
   

   Note: The qr code might have issues scanning if you have a light terminal theme. Try setting it to dark or highlighting the entire output to invert the colors.

5. Connect to spark-wallet android app

   Server Settings
   Scan QR
   Done
   

Connect to electrs

Requirements Android

• Android phone
• Orbot installed from F-Droid (recommended) or Google Play
• Electrum mobile app 4.0.1 and newer installed from direct download or Google Play

Requirements Desktop

• Tor installed from source or repository
• Electrum installed

1. Enable electrs in configuration.nix

   Change

   # services.electrs.enable = true;
   

   to

   services.electrs.enable = true;
   

2. Deploy new configuration.nix

3. Get electrs onion address with format <onion-address>:<port>

   nodeinfo | jq -r .electrs.onion_address
   

4. Connect to electrs

   Make sure Tor is running on Desktop or as Orbot on Android.

   On Desktop

   electrum --oneserver -1 -s "<electrs onion address>:t" -p socks5:localhost:9050
   

   On Android

   Three dots in the upper-right-hand corner
   Network > Proxy mode: socks5, Host: 127.0.0.1, Port: 9050
   Network > Auto-connect: OFF
   Network > One-server mode: ON
   Network > Server: <electrs onion address>:t
   

Connect to nix-bitcoin node through the SSH onion service

1. Get the SSH onion address (excluding the port suffix)

   ssh operator@bitcoin-node
   nodeinfo | jq -r .sshd.onion_address | sed 's/:.*//'
   

2. Create a SSH key

   ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519
   

3. Place the ed25519 key's fingerprint in the configuration.nix openssh.authorizedKeys.keys field like so

   # FIXME: Add your SSH pubkey
   services.openssh.enable = true;
   users.users.root = {
     openssh.authorizedKeys.keys = [ "<contents of ~/.ssh/id_ed25519.pub>" ];
   };
   

4. Connect to your nix-bitcoin node's SSH onion service, forwarding a local port to the nix-bitcoin node's SSH server

   ssh -i ~/.ssh/id_ed25519 -L <random port of your choosing>:localhost:22 root@<SSH onion address>
   

5. Edit your deployment tool's configuration and change the node's address to localhost and the ssh port to <random port of your choosing>. If you use krops as described in the installation tutorial, set target = "localhost:<random port of your choosing>"; in krops/deploy.nix.

6. After deploying the new configuration, it will connect through the SSH tunnel you established in step iv. This also allows you to do more complex SSH setups that some deployment tools don't support. An example would be authenticating with Trezor's SSH agent, which provides extra security.

Initialize a Trezor for Bitcoin Core's Hardware Wallet Interface

1. Enable Trezor in configuration.nix

   Change

   # services.hardware-wallets.trezor = true;
   

   to

   services.hardware-wallets.trezor = true;
   

2. Deploy new configuration.nix

3. Check that your nix-bitcoin node recognizes your Trezor

   ssh operator@bitcoin-node
   lsusb
   

   Should show something relating to your Trezor

4. If your Trezor has outdated firmware or is not yet initialized: Start your Trezor in bootloader mode

   Trezor v1

   Plug in your Trezor with both buttons depressed
   

   Trezor v2

   Start swiping your finger across your Trezor's touchscreen and plug in the USB cable when your finger is halfway through
   

5. If your Trezor's firmware is outdated: Update your Trezor's firmware

   trezorctl firmware-update
   

   Follow the on-screen instructions

   Caution: This command will wipe your Trezor. If you already store Bitcoin on it, only do this with the recovery seed nearby.

6. If your Trezor is not yet initialized: Set up your Trezor

   trezorctl reset-device -p
   

   Follow the on-screen instructions

7. Find your Trezor

   hwi enumerate
   hwi -t trezor -d <path from previous command> promptpin
   hwi -t trezor -d <path> sendpin <number positions for the PIN as displayed on your device's screen>
   hwi enumerate
   

8. Follow Bitcoin Core's instructions on Using Bitcoin Core with Hardware Wallets to use your Trezor with bitcoin-cli on your nix-bitcoin node

JoinMarket

Diff to regular JoinMarket usage

For clarity reasons, nix-bitcoin renames all scripts to jm-* without .py, for example wallet-tool.py becomes jm-wallet-tool. The rest of this section details nix-bitcoin specific workflows for JoinMarket.

Wallets

By default, a wallet is automatically generated at service startup. It's stored at /var/lib/joinmarket/wallets/wallet.jmdat, and its mnmenoic recovery seed phrase is stored at /var/lib/joinmarket/jm-wallet-seed.

A missing wallet file is automatically recreated if the seed file is still present.

If you want to manually initialize your wallet instead, follow these steps:

1. Enable JoinMarket in your node configuration

   services.joinmarket.enable = true;
   

2. Move the automatically generated wallet.jmdat

   mv /var/lib/joinmarket/wallet.jmdat /var/lib/joinmarket/bak.jmdat
   

3. Generate wallet on your node

   jm-wallet-tool generate
   

   Follow the on-screen instructions and write down your seed.

   In order to use nix-bitcoin's joinmarket.yieldgenerator, use the password from $secretsDir/jm-wallet-password and use the suggested default wallet name wallet.jmdat. If you want to use your own jm-wallet-password, simply replace the password string in your local secrets directory. See: Secrets dir

Run the tumbler

The tumbler needs to be able to run in the background for a long time, use screen to run it accross SSH sessions. You can also use tmux in the same fashion.

1. Add screen to your environment.systemPackages, for example

   environment.systemPackages = with pkgs; [
     vim
     screen
   ];
   

2. Start the screen session

   screen -S "tumbler"
   

3. Start the tumbler

   Example: Tumbling into your wallet after buying from an exchange to improve privacy:

   jm-tumbler wallet.jmdat <addr1> <addr2> <addr3>
   

   After tumbling your bitcoin end up in these three addresses. You can now spend them without the exchange collecting data on your purchases.

   Get more information here

4. Detach the screen session to leave the tumbler running in the background

   Ctrl-a d or Ctrl-a Ctrl-d
   

5. Re-attach to the screen session

   screen -r tumbler
   

6. End screen session

   Type exit when tumbler is done

   exit
   

Run a "maker" or "yield generator"

The maker/yield generator in nix-bitcoin is implemented using a systemd service.

See here for more yield generator information.

1. Enable yield generator bot in your node configuration

   services.joinmarket.yieldgenerator = {
     enable = true;
     # Optional: Add custom parameters
     txfee = 200;
     cjfee_a = 300;
   };
   '';
   

2. Check service status

   systemctl status joinmarket-yieldgenerator
   

3. Profit

clightning

Plugins

There is a number of plugins available for clightning. See Readme: Features → clightning or search.nixos.org for a complete list.

You can activate and configure these plugins like so:

services.clightning = {
    enable = true;
    plugins = {
        prometheus.enable = true;
        prometheus.listen = "0.0.0.0:9900";
    };
};

Please have a look at the module for a plugin (e.g. prometheus.nix) to learn its configuration options.