This document is written for people who are eager to do something with
the Lightning Network Daemon (lnd
). This folder uses docker-compose
to
package lnd
and btcd
together to make deploying the two daemons as easy as
typing a few commands. All configuration between lnd
and btcd
are handled
automatically by their docker-compose
config file.
Name | Version |
---|---|
docker-compose | 1.9.0 |
docker | 1.13.0 |
This section describes a workflow on simnet
, a development/test network
that's similar to Bitcoin Core's regtest
mode. In simnet
mode blocks can be
generated at will, as the difficulty is very low. This makes it an ideal
environment for testing as one doesn't need to wait tens of minutes for blocks
to arrive in order to test channel related functionality. Additionally, it's
possible to spin up an arbitrary number of lnd
instances within containers to
create a mini development cluster. All state is saved between instances using a
shared volume.
Current workflow is big because we recreate the whole network by ourselves,
next versions will use the started btcd
bitcoin node in testnet
and
faucet
wallet from which you will get the bitcoins.
In the workflow below, we describe the steps required to recreate the following
topology, and send a payment from Alice
to Bob
.
+ ----- + + --- +
| Alice | <--- channel ---> | Bob | <--- Bob and Alice are the lightning network daemons which
+ ----- + + --- + create channels and interact with each other using the
| | Bitcoin network as source of truth.
| |
+ - - - - - + - - - - - - +
|
+ --------------- +
| Bitcoin network | <--- In the current scenario for simplicity we create only one
+ --------------- + "btcd" node which represents the Bitcoin network, in a
real situation Alice and Bob will likely be
connected to different Bitcoin nodes.
General workflow is the following:
- Create a
btcd
node running on a privatesimnet
. - Create
Alice
, one of thelnd
nodes in our simulation network. - Create
Bob
, the otherlnd
node in our simulation network. - Mine some blocks to send
Alice
some bitcoins. - Open channel between
Alice
andBob
. - Send payment from
Alice
toBob
. - Close the channel between
Alice
andBob
. - Check that on-chain
Bob
balance was changed.
Start btcd
, and then create an address for Alice
that we'll directly mine
bitcoin into.
# Init bitcoin network env variable:
$ export NETWORK="simnet"
# Create persistent volumes for alice and bob.
$ docker volume create simnet_lnd_alice
$ docker volume create simnet_lnd_bob
# Run the "Alice" container and log into it:
$ docker-compose run -d --name alice --volume simnet_lnd_alice:/root/.lnd lnd
$ docker exec -i -t alice bash
# Generate a new backward compatible nested p2sh address for Alice:
alice $ lncli --network=simnet newaddress np2wkh
# Recreate "btcd" node and set Alice's address as mining address:
$ MINING_ADDRESS=<alice_address> docker-compose up -d btcd
# Generate 400 blocks (we need at least "100 >=" blocks because of coinbase
# block maturity and "300 ~=" in order to activate segwit):
$ docker exec -it btcd /start-btcctl.sh generate 400
# Check that segwit is active:
$ docker exec -it btcd /start-btcctl.sh getblockchaininfo | grep -A 1 segwit
Check Alice
balance:
alice $ lncli --network=simnet walletbalance
Connect Bob
node to Alice
node.
# Run "Bob" node and log into it:
$ docker-compose run -d --name bob --volume simnet_lnd_bob:/root/.lnd lnd
$ docker exec -i -t bob bash
# Get the identity pubkey of "Bob" node:
bob $ lncli --network=simnet getinfo
{
----->"identity_pubkey": "0343bc80b914aebf8e50eb0b8e445fc79b9e6e8e5e018fa8c5f85c7d429c117b38",
"alias": "",
"num_pending_channels": 0,
"num_active_channels": 0,
"num_inactive_channels": 0,
"num_peers": 0,
"block_height": 1215,
"block_hash": "7d0bc86ea4151ed3b5be908ea883d2ac3073263537bcf8ca2dca4bec22e79d50",
"synced_to_chain": true,
"testnet": false
"chains": [
"bitcoin"
]
}
# Get the IP address of "Bob" node:
$ docker inspect bob | grep IPAddress
# Connect "Alice" to the "Bob" node:
alice $ lncli --network=simnet connect <bob_pubkey>@<bob_host>
# Check list of peers on "Alice" side:
alice $ lncli --network=simnet listpeers
{
"peers": [
{
"pub_key": "0343bc80b914aebf8e50eb0b8e445fc79b9e6e8e5e018fa8c5f85c7d429c117b38",
"address": "172.19.0.4:9735",
"bytes_sent": "357",
"bytes_recv": "357",
"sat_sent": "0",
"sat_recv": "0",
"inbound": true,
"ping_time": "0"
}
]
}
# Check list of peers on "Bob" side:
bob $ lncli --network=simnet listpeers
{
"peers": [
{
"pub_key": "03d0cd35b761f789983f3cfe82c68170cd1c3266b39220c24f7dd72ef4be0883eb",
"address": "172.19.0.3:51932",
"bytes_sent": "357",
"bytes_recv": "357",
"sat_sent": "0",
"sat_recv": "0",
"inbound": false,
"ping_time": "0"
}
]
}
Create the Alice<->Bob
channel.
# Open the channel with "Bob":
alice $ lncli --network=simnet openchannel --node_key=<bob_identity_pubkey> --local_amt=1000000
# Include funding transaction in block thereby opening the channel:
$ docker exec -it btcd /start-btcctl.sh generate 3
# Check that channel with "Bob" was opened:
alice $ lncli --network=simnet listchannels
{
"channels": [
{
"active": true,
"remote_pubkey": "0343bc80b914aebf8e50eb0b8e445fc79b9e6e8e5e018fa8c5f85c7d429c117b38",
"channel_point": "3511ae8a52c97d957eaf65f828504e68d0991f0276adff94c6ba91c7f6cd4275:0",
"chan_id": "1337006139441152",
"capacity": "1005000",
"local_balance": "1000000",
"remote_balance": "0",
"commit_fee": "8688",
"commit_weight": "600",
"fee_per_kw": "12000",
"unsettled_balance": "0",
"total_satoshis_sent": "0",
"total_satoshis_received": "0",
"num_updates": "0",
"pending_htlcs": [
],
"csv_delay": 4
}
]
}
Send the payment from Alice
to Bob
.
# Add invoice on "Bob" side:
bob $ lncli --network=simnet addinvoice --amt=10000
{
"r_hash": "<your_random_rhash_here>",
"pay_req": "<encoded_invoice>",
}
# Send payment from "Alice" to "Bob":
alice $ lncli --network=simnet sendpayment --pay_req=<encoded_invoice>
# Check "Alice"'s channel balance
alice $ lncli --network=simnet channelbalance
# Check "Bob"'s channel balance
bob $ lncli --network=simnet channelbalance
Now we have open channel in which we sent only one payment, let's imagine that we sent lots of them and we'd now like to close the channel. Let's do it!
# List the "Alice" channel and retrieve "channel_point" which represents
# the opened channel:
alice $ lncli --network=simnet listchannels
{
"channels": [
{
"active": true,
"remote_pubkey": "0343bc80b914aebf8e50eb0b8e445fc79b9e6e8e5e018fa8c5f85c7d429c117b38",
---->"channel_point": "3511ae8a52c97d957eaf65f828504e68d0991f0276adff94c6ba91c7f6cd4275:0",
"chan_id": "1337006139441152",
"capacity": "1005000",
"local_balance": "990000",
"remote_balance": "10000",
"commit_fee": "8688",
"commit_weight": "724",
"fee_per_kw": "12000",
"unsettled_balance": "0",
"total_satoshis_sent": "10000",
"total_satoshis_received": "0",
"num_updates": "2",
"pending_htlcs": [
],
"csv_delay": 4
}
]
}
# Channel point consists of two numbers separated by a colon. The first one
# is "funding_txid" and the second one is "output_index":
alice $ lncli --network=simnet closechannel --funding_txid=<funding_txid> --output_index=<output_index>
# Include close transaction in a block thereby closing the channel:
$ docker exec -it btcd /start-btcctl.sh generate 3
# Check "Alice" on-chain balance was credited by her settled amount in the channel:
alice $ lncli --network=simnet walletbalance
# Check "Bob" on-chain balance was credited with the funds he received in the
# channel:
bob $ lncli --network=simnet walletbalance
{
"total_balance": "10000",
"confirmed_balance": "10000",
"unconfirmed_balance": "0"
}
In order to be more confident with lnd
commands I suggest you to try
to create a mini lightning network cluster (Create lightning network cluster).
In this section we will try to connect our node to the faucet/hub node which we will create a channel with and send some amount of bitcoins. The schema will be following:
+ ----- + + ------ + (1) + --- +
| Alice | <--- channel ---> | Faucet | <--- channel ---> | Bob |
+ ----- + + ------ + + --- +
| | |
| | | <--- (2)
+ - - - - - - - - - - - - - + - - - - - - - - - - - - - +
|
+ --------------- +
| Bitcoin network | <--- (3)
+ --------------- +
(1) You may connect an additional node "Bob" and make the multihop
payment Alice->Faucet->Bob
(2) "Faucet", "Alice" and "Bob" are the lightning network daemons which
create channels to interact with each other using the Bitcoin network
as source of truth.
(3) In current scenario "Alice" and "Faucet" lightning network nodes
connect to different Bitcoin nodes. If you decide to connect "Bob"
to "Faucet" then the already created "btcd" node would be sufficient.
First of all you need to run btcd
node in testnet
and wait for it to be
synced with test network (May the Force and Patience be with you
).
# Init bitcoin network env variable:
$ NETWORK="testnet" docker-compose up
After btcd
synced, connect Alice
to the Faucet
node.
The Faucet
node address can be found at the Faucet Lightning Community webpage.
# Run "Alice" container and log into it:
$ docker-compose run -d --name alice lnd_btc; docker exec -i -t "alice" bash
# Connect "Alice" to the "Faucet" node:
alice $ lncli --network=testnet connect <faucet_identity_address>@<faucet_host>
After a connection is achieved, the Faucet
node should create the channel
and send some amount of bitcoins to Alice
.
What you may do next?:
- Send some amount to
Faucet
node back. - Connect
Bob
node to theFaucet
and make multihop payment (Alice->Faucet->Bob
) - Close channel with
Faucet
and check the onchain balance.
Instructions on how to build standalone docker images (for development or
production), outside of docker-compose
, see the
docker docs.
- How to see
alice
|bob
|btcd
logs?
$ docker-compose logs <alice|bob|btcd>