diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b23dd2a94d70eaa404d4e1b21912a133372b8d44..8f553584760a1a2eb97894a2eaab4187b89d2cca 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,15 +1,16 @@
 variables:
   DEBIAN_FRONTEND: noninteractive
+  DOCKER_IMAGE: python:3.11-slim-bookworm
 
 stages:
   - lint
 
 lint:
   stage: lint
-  image: python:3.11-bookworm
+  image: $DOCKER_IMAGE
   script:
-  - pip install virtualenv
-  - virtualenv --python=/usr/bin/python3 .
+  - pip3 install virtualenv
+  - virtualenv .
   - source bin/activate
   - pip3 install -r requirements.txt
   - bin/pycodestyle --first --show-source --ignore=E501 *.py