diff --git a/ubuntu/16.04/usr/local/bin/container b/ubuntu/16.04/usr/local/bin/container
index cbbd2b31..bf3e964e 100755
--- a/ubuntu/16.04/usr/local/bin/container
+++ b/ubuntu/16.04/usr/local/bin/container
@@ -1,5 +1,5 @@
 #!/bin/bash
-set -e
+set -e -u
 
 TASK=$1
 ARGS=( "$@" )
@@ -28,4 +28,4 @@ fi
 set -- "${ARGS[@]}"
 shift 1
 
-"do_$TASK" "$@"
\ No newline at end of file
+"do_$TASK" "$@"