diff --git a/ansible/roles/horizon/tasks/start.yml b/ansible/roles/horizon/tasks/start.yml
index bae0c1640c..d7eb056d71 100644
--- a/ansible/roles/horizon/tasks/start.yml
+++ b/ansible/roles/horizon/tasks/start.yml
@@ -11,6 +11,7 @@
       ENABLE_MANILA: "{{ 'yes' if enable_manila | bool else 'no' }}"
       ENABLE_MISTRAL: "{{ 'yes' if enable_mistral | bool else 'no' }}"
       ENABLE_NEUTRON_LBAAS: "{{ 'yes' if enable_neutron_lbaas | bool else 'no' }}"
+      ENABLE_MAGNUM: "{{ 'yes' if enable_magnum | bool else 'no' }}"
       ENABLE_SAHARA: "{{ 'yes' if enable_sahara | bool else 'no' }}"
       ENABLE_SEARCHLIGHT: "{{ 'yes' if enable_searchlight | bool else 'no' }}"
       ENABLE_SENLIN: "{{ 'yes' if enable_senlin | bool else 'no' }}"