diff --git a/tests/roles/bootstrap-host/templates/user_variables.aio.yml.j2 b/tests/roles/bootstrap-host/templates/user_variables.aio.yml.j2
index 2d459762f4..92e449f097 100644
--- a/tests/roles/bootstrap-host/templates/user_variables.aio.yml.j2
+++ b/tests/roles/bootstrap-host/templates/user_variables.aio.yml.j2
@@ -177,9 +177,13 @@ cache_timeout: {{ cache_timeout }}
 repo_build_git_cache: {{ repo_build_git_cache }}
 {% endif %}
 
-# The container backing store is set to 'overlayfs' to speed up the
-# AIO build time.
-lxc_container_backing_store: "{{ (ansible_kernel | version_compare('3.18.0-0-generic', '<')) | ternary('dir', 'overlayfs') }}"
+# The container backing store is set to 'machinectl' to speed up the
+# AIO build time. Options are: [machinectl, overlayfs, btrfs, zfs, dir, lvm]
+lxc_container_backing_store: "machinectl"
+
+# Allow the container store sufficient space to build everything we need.
+#  Size is in GB:
+lxc_host_machine_volume_size: 1024
 
 ## Enable LBaaSv2 in the AIO
 neutron_plugin_base: