Squashfs not saved

.gitlab-ci.yml

@@ -96,13 +96,13 @@ variables:
 spack:checkout:
   stage: .pre
   variables:
-    APPTAINER_EXEC_OPTIONS: --cleanenv --bind ${CI_DATA}
+    APPTAINER_EXEC_OPTIONS: --cleanenv --bind ${CI_DATA} --bind ${CI_DATA}/squashfs-cache:/squashfs-cache
   extends:
     - .parallel_definition
   before_script:
     - git config --global --add --bool advice.detachedHead false
   script:
-    - mkdir -p ${CI_DATA}/overlayfs
+    - mkdir -p ${CI_DATA}/overlayfs/{lower,upper,wd}
     - mkdir -p ${CI_DATA}/squashfs-cache
     - mkdir -p ${CI_DATA}/buildcache
     - mkdir -p ${CI_DATA}/spack-mirror

ci/prepare_squashfs.sh

@@ -21,9 +21,9 @@ then
     then
         echo "No default branch ($squash_base) squashfs found"
         echo "Creating an empty one"
-        mkdir /tmp/empty
+        empty=(mktemp -d)
         sqfs_base_image=/squashfs-cache/${stack}-${environment}-${squash_base}-initial.sqfs
-        mksquashfs /tmp/empty ${sqfs_base_image}
+        mksquashfs ${empty} ${sqfs_base_image}
     else
         echo "Found ${sqfs_base_image}"
     fi