+Background:
+
+This script does not make the namespace be named like ip does, because
+the naming is not necessary, although it could have been done with some
+more work. For debugging and joining the namespace with a bash shell, I
+use nsenter -n -m -t $(pgrep PROCESS_IN_NAMESPACE). Note: if I knew how
+to easily ask systemd what pid a unit has, i would do that.
+
+"ip netns new ..." also does a mount namespace, then bind