diff --git a/metropolis/node/ids.go b/metropolis/node/ids.go
new file mode 100644
index 0000000..b4ddf84
--- /dev/null
+++ b/metropolis/node/ids.go
@@ -0,0 +1,24 @@
+// Copyright 2021 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package node
+
+// These are UID/GID constants for components inside the Metropolis node
+// code.
+const (
+	RootUid = 0
+	TimeUid = 100
+)