diff --git a/docker-gitlabci/Dockerfile b/docker-gitlabci/Dockerfile
index 81f4f45..e759c5e 100644
--- a/docker-gitlabci/Dockerfile
+++ b/docker-gitlabci/Dockerfile
@@ -61,3 +61,14 @@ RUN wget $GITHUBDICTIONARY -O $CODESPELLDICTLOCATION
 # Do some extra setup
 RUN mkdir -p /run/php \
  && rm /etc/php/*/fpm/pool.d/www.conf
+
+RUN du -sh /*
+
+# Cache the chroot
+RUN wget https://github.com/DOMjudge/domjudge/archive/refs/heads/main.zip \
+ && unzip main.zip && cd domjudge-main/misc-tools && make configure \
+ && cd misc-tools && make dj_make_chroot \
+ && ./dj_make_chroot \
+ && cd ../.. && rm -rf domjudge-main
+
+RUN du -sh /*