nebula

modules/nixos/services/nebula/default.nix

@@ -31,6 +31,13 @@ let
         lib.${namespace}.mkOpt types.str "jallen-nebula"
           "Nebula network name (used as the systemd service suffix and interface name)";
 
+      # Linux interface names are capped at 15 characters. Nebula derives the
+      # default tun device name as "nebula.<networkName>" which easily exceeds
+      # that limit. Set an explicit short name here to avoid silent truncation.
+      tunDevice =
+        lib.${namespace}.mkOpt (types.nullOr types.str) null
+          "Explicit tun device name (max 15 chars). Defaults to nebula0 when unset.";
+
       # -----------------------------------------------------------------------
       # SOPS secret location
       #
@@ -114,6 +121,8 @@ let
         lighthouses = cfg.lighthouses;
         staticHostMap = cfg.staticHostMap;
 
+        tun.device = if cfg.tunDevice != null then cfg.tunDevice else "nebula0";
+
         listen = {
           host = cfg.listenAddress;
           port = cfg.port;