Try this to mask the failure

tasks/persistent_cloud.yml

@@ -51,6 +51,7 @@
 - local_action: shell nova --os-auth-url="{{os_auth_url}}" --os-username="admin" --os-password="{{ADMIN_PASS}}" --os-tenant-name={{inventory_tenant}} volume-list | grep ' {{item.volume_id}} ' | grep 'available' 
   with_items: "{{volumes}}"
   register: volume_available
+  failed_when: volume_available.rc == 2
   ignore_errors: True
   when: volumes is defined