# Experimental etcd support in LND With the recent introduction of the `kvdb` interface LND can support multiple database backends allowing experimentation with the storage model as well as improving robustness trough eg. replicating essential data. Building on `kvdb` in v0.11.0 we're adding experimental [etcd](https://etcd.io) support to LND. As this is an unstable feature heavily in development, it still has *many* rough edges for the time being. It is therefore highly recommended to not use LND on `etcd` in any kind of production environment especially not on bitcoin mainnet. ## Building LND with etcd support To create a dev build of LND with etcd support use the following command: ``` make tags="kvdb_etcd" ``` The important tag is the `kvdb_etcd`, without which the binary is built without the etcd driver. For development it is advised to set the `GOFLAGS` environment variable to `"-tags=test"` otherwise `gopls` won't work on code in `channeldb/kvdb/etcd` directory. ## Running a local etcd instance for testing To start your local etcd instance for testing run: ``` ./etcd \ --auto-tls \ --advertise-client-urls=https://127.0.0.1:2379 \ --listen-client-urls=https://0.0.0.0:2379 \ --max-txn-ops=16384 \ --max-request-bytes=104857600 ``` The large `max-txn-ops` and `max-request-bytes` values are currently required in case of running LND with the full graph in etcd. Upcoming versions will split the database to local and replicated parts and only essential parts will remain in the replicated database, removing the requirement for these additional settings. These parameters have been tested to work with testnet LND. ## Configuring LND to run on etcd To run LND with etcd, additional configuration is needed, specified either through command line flags or in `lnd.conf`. Sample command line: ``` ./lnd-debug \ --db.backend=etcd \ --db.etcd.host=127.0.0.1:2379 \ --db.etcd.certfile=/home/user/etcd/bin/default.etcd/fixtures/client/cert.pem \ --db.etcd.keyfile=/home/user/etcd/bin/default.etcd/fixtures/client/key.pem \ --db.etcd.insecure_skip_verify ``` Sample `lnd.conf` (with other setting omitted): ``` [db] backend=etcd etcd.host=127.0.0.1:2379 etcd.cerfile=/home/user/etcd/bin/default.etcd/fixtures/client/cert.pem etcd.keyfile=/home/user/etcd/bin/default.etcd/fixtures/client/key.pem etcd.insecure_skip_verify=true ``` Optionally users can specifiy `db.etcd.user` and `db.etcd.pass` for db user authentication. ## Migrating existing channel.db to etcd This is currently not supported. ## Disclaimer As mentioned before this is an experimental feature, and with that your data may be lost. Use at your own risk!