diff --git a/ansible/group_vars/all.yml b/ansible/group_vars/all.yml
index fda3a75322..c8ec7acfef 100644
--- a/ansible/group_vars/all.yml
+++ b/ansible/group_vars/all.yml
@@ -515,7 +515,10 @@ keystone_default_user_role: "_member_"
 #######################
 # Glance options
 #######################
-glance_backend_file: "{{ not enable_ceph | bool }}"
+# Using glance_backend_ceph rather than enable_ceph to determine whether to
+# use the file backend, as this allows for the external ceph case, where
+# enable_ceph is False.
+glance_backend_file: "{{ not glance_backend_ceph | bool }}"
 glance_backend_ceph: "{{ enable_ceph }}"
 glance_backend_vmware: "no"
 glance_backend_swift: "no"