diff --git a/mkosi.postinst b/mkosi.postinst
new file mode 100755
index 0000000000..1bbb9e41c5
--- /dev/null
+++ b/mkosi.postinst
@@ -0,0 +1,5 @@
+#!/bin/sh
+set -e
+
+mkdir -p /root/build
+echo "directory /root/build" > ~/.gdbinit