Table of Contents

Installation

Preliminaries

In order to work with lnd, the following build dependencies are required:

  • Go: lnd is written in Go. To install, run one of the following commands:

    Note: The minimum version of Go supported is Go 1.11. We recommend that users use the latest version of Go, which at the time of writing is 1.11.

    On Linux:

    sudo apt-get install golang-1.11-go
    

    Note that golang-1.11-go puts binaries in /usr/lib/go-1.11/bin. If you want them on your PATH, you need to make that change yourself. Alternatively, you can run:

    sudo ln -s /usr/lib/go-1.11/bin/go /usr/local/bin/go
    

    On Mac OS X:

    brew install go
    

    On FreeBSD:

    pkg install go
    

    Alternatively, one can download the pre-compiled binaries hosted on the golang download page. If one seeks to install from source, then more detailed installation instructions can be found here.

    At this point, you should set your $GOPATH environment variable, which represents the path to your workspace. By default, $GOPATH is set to ~/go. You will also need to add $GOPATH/bin to your PATH. This ensures that your shell will be able to detect the binaries you install.

    export GOPATH=~/gocode
    export PATH=$PATH:$GOPATH/bin
    

    We recommend placing the above in your .bashrc or in a setup script so that you can avoid typing this every time you open a new terminal window.

  • go modules: This project uses go modules to manage dependencies as well as to provide reproducible builds.

    Usage of go modules (with go 1.11) means that you no longer need to clone lnd into your $GOPATH for development purposes. Instead, your lnd repo can now live anywhere!

Installing lnd

With the preliminary steps completed, to install lnd, lncli, and all related dependencies run the following commands:

go get -d github.com/lightningnetwork/lnd
cd $GOPATH/src/github.com/lightningnetwork/lnd
make && make install

NOTE: Our instructions still use the $GOPATH directory from prior versions of Go, but with go 1.11, it’s now possible for lnd to live anywhere on your file system.

For Windows WSL users, make will need to be referenced directly via /usr/bin/make/, or alternatively by wrapping quotation marks around make, like so:

/usr/bin/make && /usr/bin/make install

"make" && "make" install

On FreeBSD, use gmake instead of make.

Alternatively, if one doesn’t wish to use make, then the go commands can be used directly:

GO111MODULE=on go install -v ./...

Updating

To update your version of lnd to the latest version run the following commands:

cd $GOPATH/src/github.com/lightningnetwork/lnd
git pull
make clean && make && make install

On FreeBSD, use gmake instead of make.

Alternatively, if one doesn’t wish to use make, then the go commands can be used directly:

cd $GOPATH/src/github.com/lightningnetwork/lnd
git pull
GO111MODULE=on go install -v ./...

Tests

To check that lnd was installed properly run the following command:

make check

Available Backend Operating Modes

In order to run, lnd requires, that the user specify a chain backend. At the time of writing of this document, there are three available chain backends: btcd, neutrino, bitcoind. All but neutrino (atm) can run on mainnet with an out of the box lnd instance. We don’t require --txindex when running with bitcoind or btcd but activating the txindex will generally make lnd run faster.

NOTE: WE DO NOT FULLY SUPPORT PRUNED OPERATING MODES FOR FULL NODES. It’s possible to run a node in a pruned mode and have it serve lnd, however one must take care to ensure that lnd has all blocks on disk since the birth of the wallet, and the age of the earliest channels (which were created around March 2018).

The set of arguments for each of the backend modes is as follows:

btcd Options

btcd:
      --btcd.dir=                                             The base directory that contains the node's data, logs, configuration file, etc. (default: /Users/roasbeef/Library/Application Support/Btcd)
      --btcd.rpchost=                                         The daemon's rpc listening address. If a port is omitted, then the default port for the selected chain parameters will be used. (default: localhost)
      --btcd.rpcuser=                                         Username for RPC connections
      --btcd.rpcpass=                                         Password for RPC connections
      --btcd.rpccert=                                         File containing the daemon's certificate file (default: /Users/roasbeef/Library/Application Support/Btcd/rpc.cert)
      --btcd.rawrpccert=                                      The raw bytes of the daemon's PEM-encoded certificate chain which will be used to authenticate the RPC connection.

Neutrino Options

neutrino:
  -a, --neutrino.addpeer=                                     Add a peer to connect with at startup
      --neutrino.connect=                                     Connect only to the specified peers at startup
      --neutrino.maxpeers=                                    Max number of inbound and outbound peers
      --neutrino.banduration=                                 How long to ban misbehaving peers.  Valid time units are {s, m, h}.  Minimum 1 second
      --neutrino.banthreshold=                                Maximum allowed ban score before disconnecting and banning misbehaving peers.

Bitcoind Options

bitcoind:
      --bitcoind.dir=                                         The base directory that contains the node's data, logs, configuration file, etc. (default: /Users/roasbeef/Library/Application Support/Bitcoin)
      --bitcoind.rpchost=                                     The daemon's rpc listening address. If a port is omitted, then the default port for the selected chain parameters will be used. (default: localhost)
      --bitcoind.rpcuser=                                     Username for RPC connections
      --bitcoind.rpcpass=                                     Password for RPC connections
      --bitcoind.zmqpubrawblock=                              The address listening for ZMQ connections to deliver raw block notifications
      --bitcoind.zmqpubrawtx=                                 The address listening for ZMQ connections to deliver raw transaction notifications

Using btcd

Installing btcd

On FreeBSD, use gmake instead of make.

To install btcd, run the following commands:

Install btcd:

make btcd

Alternatively, you can install btcd directly from its repo.

Starting btcd

Running the following command will create rpc.cert and default btcd.conf.

btcd --testnet --rpcuser=REPLACEME --rpcpass=REPLACEME

If you want to use lnd on testnet, btcd needs to first fully sync the testnet blockchain. Depending on your hardware, this may take up to a few hours. Note that adding --txindex is optional, as it will take longer to sync the node, but then lnd will generally operate faster as it can hit the index directly, rather than scanning blocks or BIP 158 filters for relevant items.

(NOTE: It may take several minutes to find segwit-enabled peers.)

While btcd is syncing you can check on its progress using btcd’s getinfo RPC command:

btcctl --testnet --rpcuser=REPLACEME --rpcpass=REPLACEME getinfo
{
  "version": 120000,
  "protocolversion": 70002,
  "blocks": 1114996,
  "timeoffset": 0,
  "connections": 7,
  "proxy": "",
  "difficulty": 422570.58270815,
  "testnet": true,
  "relayfee": 0.00001,
  "errors": ""
}

Additionally, you can monitor btcd’s logs to track its syncing progress in real time.

You can test your btcd node’s connectivity using the getpeerinfo command:

btcctl --testnet --rpcuser=REPLACEME --rpcpass=REPLACEME getpeerinfo | more

Running lnd using the btcd backend

If you are on testnet, run this command after btcd has finished syncing. Otherwise, replace --bitcoin.testnet with --bitcoin.simnet. If you are installing lnd in preparation for the tutorial, you may skip this step.

lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --btcd.rpcuser=kek --btcd.rpcpass=kek --externalip=X.X.X.X

Using Neutrino

In order to run lnd in its light client mode, you’ll need to locate a full-node which is capable of serving this new light client mode. lnd uses BIP 157 and BIP 158 for its light client mode. A public instance of such a node can be found at faucet.lightning.community.

To run lnd in neutrino mode, run lnd with the following arguments, (swapping in --bitcoin.simnet if needed), and also your own btcd node if available:

lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.node=neutrino --neutrino.connect=faucet.lightning.community

Using bitcoind or litecoind

The configuration for bitcoind and litecoind are nearly identical, the following steps can be mirrored with loss of generality to enable a litecoind backend. Setup will be described in regards to bitcoind, but note that lnd uses a distinct litecoin.node=litecoind argument and analogous subconfigurations prefixed by litecoind. Note that adding --txindex is optional, as it will take longer to sync the node, but then lnd will generally operate faster as it can hit the index directly, rather than scanning blocks or BIP 158 filters for relevant items.

To configure your bitcoind backend for use with lnd, first complete and verify the following:

  • Since lnd uses ZeroMQ to interface with bitcoind, your bitcoind installation must be compiled with ZMQ. Note that if you installed bitcoind from source and ZMQ was not present, then ZMQ support will be disabled, and lnd will quit on a connection refused error. If you installed bitcoind via Homebrew in the past ZMQ may not be included (this has now been fixed in the latest Homebrew recipe for bitcoin)
  • Configure the bitcoind instance for ZMQ with --zmqpubrawblock and --zmqpubrawtx. These options must each use their own unique address in order to provide a reliable delivery of notifications (e.g. --zmqpubrawblock=tcp://127.0.0.1:28332 and --zmqpubrawtx=tcp://127.0.0.1:28333).
  • Start bitcoind running against testnet, and let it complete a full sync with the testnet chain (alternatively, use --bitcoind.regtest instead).

Here’s a sample bitcoin.conf for use with lnd:

testnet=1
server=1
daemon=1
zmqpubrawblock=tcp://127.0.0.1:28332
zmqpubrawtx=tcp://127.0.0.1:28333

Once all of the above is complete, and you’ve confirmed bitcoind is fully updated with the latest blocks on testnet, run the command below to launch lnd with bitcoind as your backend (as with bitcoind, you can create an lnd.conf to save these options, more info on that is described further below):

lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.node=bitcoind --bitcoind.rpcuser=REPLACEME --bitcoind.rpcpass=REPLACEME --bitcoind.zmqpubrawblock=tcp://127.0.0.1:28332 --bitcoind.zmqpubrawtx=tcp://127.0.0.1:28333 --externalip=X.X.X.X

NOTE:

  • The auth parameters rpcuser and rpcpass parameters can typically be determined by lnd for a bitcoind instance running under the same user, including when using cookie auth. In this case, you can exclude them from the lnd options entirely.
  • If you DO choose to explicitly pass the auth parameters in your lnd.conf or command line options for lnd (bitcoind.rpcuser and bitcoind.rpcpass as shown in example command above), you must also specify the bitcoind.zmqpubrawblock and bitcoind.zmqpubrawtx options. Otherwise, lnd will attempt to get the configuration from your bitcoin.conf.
  • You must ensure the same addresses are used for the bitcoind.zmqpubrawblock and bitcoind.zmqpubrawtx options passed to lnd as for the zmqpubrawblock and zmqpubrawtx passed in the bitcoind options respectively.
  • When running lnd and bitcoind on the same Windows machine, ensure you use 127.0.0.1, not localhost, for all configuration options that require a TCP/IP host address. If you use “localhost” as the host name, you may see extremely slow inter-process-communication between lnd and the bitcoind backend. If lnd is experiencing this issue, you’ll see “Waiting for chain backend to finish sync, start_height=XXXXXX” as the last entry in the console or log output, and lnd will appear to hang. Normal lnd output will quickly show multiple messages like this as lnd consumes blocks from bitcoind.
  • Don’t connect more than two or three instances of lnd to bitcoind. With the default bitcoind settings, having more than one instance of lnd, or lnd plus any application that consumes the RPC could cause lnd to miss crucial updates from the backend.

Macaroons

lnd’s authentication system is called macaroons, which are decentralized bearer credentials allowing for delegation, attenuation, and other cool features. You can learn more about them in Alex Akselrod’s writeup on Github.

Running lnd for the first time will by default generate the admin.macaroon, read_only.macaroon, and macaroons.db files that are used to authenticate into lnd. They will be stored in the network directory (default: lnddir/data/chain/bitcoin/mainnet) so that it’s possible to use a distinct password for mainnet, testnet, simnet, etc. Note that if you specified an alternative data directory (via the --datadir argument), you will have to additionally pass the updated location of the admin.macaroon file into lncli using the --macaroonpath argument.

To disable macaroons for testing, pass the --no-macaroons flag into both lnd and lncli.

Network Reachability

If you’d like to signal to other nodes on the network that you’ll accept incoming channels (as peers need to connect inbound to initiate a channel funding workflow), then the --externalip flag should be set to your publicly reachable IP address.

Simnet vs. Testnet Development

If you are doing local development, such as for the tutorial, you’ll want to start both btcd and lnd in the simnet mode. Simnet is similar to regtest in that you’ll be able to instantly mine blocks as needed to test lnd locally. In order to start either daemon in the simnet mode use simnet instead of testnet, adding the --bitcoin.simnet flag instead of the --bitcoin.testnet flag.

Another relevant command line flag for local testing of new lnd developments is the --debughtlc flag. When starting lnd with this flag, it’ll be able to automatically settle a special type of HTLC sent to it. This means that you won’t need to manually insert invoices in order to test payment connectivity. To send this “special” HTLC type, include the --debugsend command at the end of your sendpayment commands.

There are currently two primary ways to run lnd: one requires a local btcd instance with the RPC service exposed, and the other uses a fully integrated light client powered by neutrino.

Creating an lnd.conf (Optional)

Optionally, if you’d like to have a persistent configuration between lnd launches, allowing you to simply type lnd --bitcoin.testnet --bitcoin.active at the command line, you can create an lnd.conf.

On MacOS, located at: /Users/[username]/Library/Application Support/Lnd/lnd.conf

On Linux, located at: ~/.lnd/lnd.conf

Here’s a sample lnd.conf for btcd to get you started:

[Application Options]
debuglevel=trace
maxpendingchannels=10

[Bitcoin]
bitcoin.active=1

Notice the [Bitcoin] section. This section houses the parameters for the Bitcoin chain. lnd also supports Litecoin testnet4 (but not both BTC and LTC at the same time), so when working with Litecoin be sure to set to parameters for Litecoin accordingly. See a more detailed sample config file available here and explore the other sections for node configuration, including [Btcd], [Bitcoind], [Neutrino], [Ltcd], and [Litecoind] depending on which chain and node type you’re using.