diff --git a/machines/prattle/default.nix b/machines/prattle/default.nix
index 90f9bd8..6fbf9c4 100644
--- a/machines/prattle/default.nix
+++ b/machines/prattle/default.nix
@@ -168,6 +168,7 @@
         "wheel"
         "media"
         "cdrom"
+        "docker" # drive the daemon over DOCKER_HOST=ssh (kloe's kata sandbox)
       ];
     };
     root.openssh.authorizedKeys.keys = [