diff --git a/ci/apptainer_by_hand.sh b/ci/apptainer_by_hand.sh
index f81f783b4e6005fb92a9a67ec612e1696cd8a7ce..6acf29219ffd8a46971aa0cfad2b294c93ea5e37 100755
--- a/ci/apptainer_by_hand.sh
+++ b/ci/apptainer_by_hand.sh
@@ -26,7 +26,6 @@ do
     fi
 done
 
-
 if [ ! -f ${CI_DATA}/squashfs-cache/${stack}-${environment}-${SQUASHFS_ID}.sqfs ]
 then
     empty=$(mktemp -d)
@@ -40,19 +39,20 @@ fi
 
 srun ${srun_options} --pty apptainer run \
     ${apptainer_options}\
-   --cleanenv \
-   -H $(mktemp -d -p ${FAKEHOME}/):/home/$(id -un) \
-   --bind ${CI_DATA}/buildcache:${MOUNT_POINT}/buildcache \
-   --bind ${CI_DATA}/spack-mirror:${MOUNT_POINT}/spack-mirror \
-   --bind ${CI_DATA}/squashfs-cache/:/squashfs-cache \
-   --bind ${CI_DATA}/overlayfs:/overlayfs \
-   --env stack=${stack} \
-   --env environment=${environment} \
-   --env GPG_PRIVATE_KEY=${GPG_PRIVATE_KEY} \
-   --env CI_PROJECT_DIR=${CI_PROJECT_DIR} \
-   --env CI_JOB_ID=${CI_JOB_ID} \
-   --env SQUASHFS_ID=${SQUASHFS_ID} \
-   --fusemount "host:/usr/libexec/apptainer/bin/squashfuse_ll ${CI_DATA}/squashfs-cache/${stack}-${environment}-${SQUASHFS_ID}.sqfs /overlayfs/lower-${SQUASHFS_ID}-${CI_JOB_ID}" \
-   --fusemount "host:${CI_PROJECT_DIR}/ci/fuse-overlayfs.sh ${CI_DATA} ${SQUASHFS_ID}-${CI_JOB_ID} ${MOUNT_POINT}/${stack}/${environment}/${STACK_VERSION}" \
-   ${APPTAINER_IMAGE}
-   bash
+    --writable-tmpfs \
+    --cleanenv \
+    -H $(mktemp -d -p ${FAKEHOME}/):/home/$(id -un) \
+    --bind ${CI_DATA}/buildcache:${MOUNT_POINT}/buildcache \
+    --bind ${CI_DATA}/spack-mirror:${MOUNT_POINT}/spack-mirror \
+    --bind ${CI_DATA}/squashfs-cache/:/squashfs-cache \
+    --bind ${CI_DATA}/overlayfs:/overlayfs \
+    --env stack=${stack} \
+    --env environment=${environment} \
+    --env GPG_PRIVATE_KEY=${GPG_PRIVATE_KEY} \
+    --env CI_PROJECT_DIR=${CI_PROJECT_DIR} \
+    --env CI_JOB_ID=${CI_JOB_ID} \
+    --env SQUASHFS_ID=${SQUASHFS_ID} \
+    --fusemount "host:/usr/libexec/apptainer/bin/squashfuse_ll ${CI_DATA}/squashfs-cache/${stack}-${environment}-${SQUASHFS_ID}.sqfs /overlayfs/lower-${SQUASHFS_ID}-${CI_JOB_ID}" \
+    --fusemount "host:${CI_PROJECT_DIR}/ci/fuse-overlayfs.sh ${CI_DATA} ${SQUASHFS_ID}-${CI_JOB_ID} ${MOUNT_POINT}/${stack}/${environment}/${STACK_VERSION}" \
+    ${APPTAINER_IMAGE} \
+    bash