Check that DinD uses the overlay2 storage driver:

As hook-docker uses the overlay2 storage driver
the DinD image must use the overlay2 storage driver too.

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>

Author: jacobweinstock

images/hook-embedded/pull-images.sh

@@ -70,6 +70,15 @@ function main() {
         fi
     done
 
+    # As hook-docker uses the overlay2 storage driver the DinD must use the overlay2 storage driver too.
+    # make sure the overlay2 storage driver is used by the DinD container.
+    # The VFS storage driver might get used if /var/lib/docker in the DinD container cannot be used by overlay2.
+    storage_driver=$(docker exec "${dind_container}" docker info --format '{{.Driver}}')
+    if [[ "${storage_driver}" != "overlay2" ]]; then
+        echo "DinD container is not using overlay2 storage driver"
+        exit 1
+    fi
+
     # remove the contents of /var/lib/docker-embedded so that any previous images are removed. Without this it seems to cause boot issues.
     docker exec "${dind_container}" sh -c "rm -rf /var/lib/docker-embedded/*"