feat(CI,JUSUF): transparent base image

.gitlab-ci.yml

@@ -285,14 +285,33 @@ build-esd-image_JUSUF:
     # create a sandbox/image for performing an spack install inside based on some base image/install
     - rm -rf $TMPDIR
     - mkdir $TMPDIR || true
-    - apptainer build --fix-perms --force --sandbox ${SANDBOX_ROOT}/ docker://${BUILD_ENV_DOCKER_IMAGE}
+    - |
+      cat <<EOF >image.def
+      Bootstrap: scratch
+      
+      %setup
+          mkdir \${APPTAINER_ROOTFS}/bin
+          # /etc exists
+          touch \${APPTAINER_ROOTFS}/etc/passwd
+          touch \${APPTAINER_ROOTFS}/etc/group
+          touch \${APPTAINER_ROOTFS}/etc/localtime
+          mkdir \${APPTAINER_ROOTFS}/lib
+          mkdir \${APPTAINER_ROOTFS}/lib64
+          mkdir \${APPTAINER_ROOTFS}/usr
+          mkdir -p \${APPTAINER_ROOTFS}/${INSTALLATION_ROOT}
+          # JUSUF speciale
+          mkdir \${APPTAINER_ROOTFS}/p
+          mkdir -p \${APPTAINER_ROOTFS}/etc/FZJ
+          # /var exists
+      EOF
+    - cat image.def
+    - apptainer build --fix-perms --force --sandbox ${SANDBOX_ROOT}/ image.def
     # run installation script inside future container environment
     #   => DAG concretization, subsequent cache access + fetching and actual build should be separate steps
-    - mkdir --mode=0777 -p ${SANDBOX_ROOT}/${INSTALLATION_ROOT}
     # begin of fixup for JUSUF
-    - mkdir --mode=0777 -p ${SANDBOX_ROOT}/p
-    - mkdir --mode=0777 -p ${SANDBOX_ROOT}/etc/FZJ
     # end of fixup for JUSUF
+    - export APPTAINER_BIND="/bin,/lib,/lib64,/usr,/p,/etc/FZJ"
+    - apptainer exec --writable --fakeroot --cwd / ${SANDBOX_ROOT} bash -c "which python3"
     - apptainer exec --writable --bind ${CI_PROJECT_DIR}:${INSTALLATION_ROOT} --cwd ${INSTALLATION_ROOT} ${SANDBOX_ROOT} bash ./install_spack_env.sh $SPACK_JOBS $INSTALLATION_ROOT ${INSTALLATION_ROOT} $CI_SPACK_ENV "" $UPDATE_SPACK_OCI_CACHES $OCI_CACHE_PREFIX
     - echo "export SYSTEMNAME=${SYSTEMNAME}" >> ${SANDBOX_ROOT}/.singularity.d/env/90-environment.sh
     - echo ". ${INSTALLATION_ROOT}/vendor/spack/var/spack/environments/${CI_SPACK_ENV}/load_env.sh" >> ${SANDBOX_ROOT}/.singularity.d/env/90-environment.sh