backups: add module

examples/configuration.nix

@@ -137,6 +137,27 @@
   # interact with off/on chain bridge using `loop in` and `loop out`.
   # services.lightning-loop.enable = true;
 
+  ### Backups
+  # Enable this module to use nix-bitcoin's own backups module. By default, it
+  # uses duplicity to incrementally back up all important files in /var/lib to
+  # /var/lib/localBackups once a day.
+  # services.backups.enable = true;
+  # You can pull the localBackups folder with
+  # `nixops scp --from bitcoin-node /var/lib/localBackups /my-backup-path/`
+  # Alternatively, you can also set a remote target url, for example
+  # services.backups.destination = "sftp://user@host[:port]/[relative|/absolute]_path";
+  # Supply the sftp password by appending the FTP_PASSWORD environment variable
+  # to secrets/backup-encryption-env like so
+  # `echo "FTP_PASSWORD=<password>" >> secrets/backup-encryption-env`
+  # You many also need to set a ssh host and publickey with
+  # programs.ssh.knownHosts."host" = {
+  #   hostNames = [ "host" ];
+  #   publicKey = "<ssh public from `ssh-keyscan`>";
+  # };
+  # If you also want to backup bulk data like the Bitcoin & Liquid blockchains
+  # and electrs data directory, enable
+  # services.backups.with-bulk-data = true;
+
   # FIXME: Define your hostname.
   networking.hostName = "nix-bitcoin";
   time.timeZone = "UTC";