diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 259b6021ca630d3dd33ac33001ed7926da5ea91b..ef29f39f598f7f8198b0a1f8f2dc411c0bcc8138 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,6 +4,7 @@ variables:
   GIT_SUBMODULE_STRATEGY: recursive
 
 cache:
+  key: sphinx-build-env-docs-001
   paths:
   - .venv
   - .cache
diff --git a/venv-build-env.sh b/venv-build-env.sh
index 5993ce8fe0f73655fd882f6bd5a612b3c5867767..ea57e6d5037f20a52bb59912ed38025a03c2b6e3 100755
--- a/venv-build-env.sh
+++ b/venv-build-env.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/sh -ex
 # Source this script like `. ./venv-build-env.sh`
 if [ ! -e ./.venv ]; then
    python3 -m venv .venv