diff --git a/travis-ci/managers/debian.sh b/travis-ci/managers/debian.sh
index 61f1adf..66fccbf 100755
--- a/travis-ci/managers/debian.sh
+++ b/travis-ci/managers/debian.sh
@@ -21,7 +21,7 @@ function docker_exec() {
     docker exec $ENV_VARS -it $CONT_NAME "$@"
 }
 
-set -e
+set -eu
 
 source "$(dirname $0)/travis_wait.bash"
 
diff --git a/travis-ci/managers/ubuntu.sh b/travis-ci/managers/ubuntu.sh
index 2229dc6..e317488 100755
--- a/travis-ci/managers/ubuntu.sh
+++ b/travis-ci/managers/ubuntu.sh
@@ -1,6 +1,5 @@
 #!/bin/bash
-set -e
-set -x
+set -eux
 
 RELEASE="bionic"