How to connect LND to bitcoind RPC with authentication cookie stored in a custom folder?

Question

I configured bitcoind RPC to authenticate clients with an authentication cookie. However I cant figure out if it's possible to use this method with lnd while connecting to bitcoind RPC.

I would like to clarify that I'm running bitcoind and lnd in two separated docker containers that share a volume where bitcoind save the authentication cookie. The problem is that lnd doesn't allow to specify the folder in which it could find the cookie... In bitcoin.conf for exemple you can specify the path where you can find the authentication cookie of the tor control port for example...

Someone knows how to do this in lnd ? Is it possible ?

Thank you!

Answer 1

It is supported according to the LND installation guide

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.

Answer 2

The auth cookie lives in the data_dir for bitcoind.

lnd finds the data_dir by first finding the bitcoin.conf file, which it finds based on the bitcoind.dir argument passed at runtime. It then parses that for the data_dir directive.

You can see this in the src code: https://github.com/lightningnetwork/lnd/blob/master/config.go#L1505

So, if you are using a non-default location for your data_dir you need to ensure that you have a data_dir directive in your bitcoin.conf file and that you pass the bitcoind.dir at runtime.

Note: lnd won't find your data_dir directive if you preface it with main ot test.