diff --git a/ansible/roles/vm_set/tasks/main.yml b/ansible/roles/vm_set/tasks/main.yml
index 1285584347a..7d5b4475dac 100644
--- a/ansible/roles/vm_set/tasks/main.yml
+++ b/ansible/roles/vm_set/tasks/main.yml
@@ -175,7 +175,7 @@
         home_path: "{{ getent_passwd[ansible_user][4] }}"
       when: home_path is not defined
 
-    # root_path is supposed to be absolute path. 
+    # root_path is supposed to be absolute path.
     - set_fact:
         root_path: "{{ home_path + '/' + root_path }}"
       when: "not '{{ root_path }}'.startswith('/')"
@@ -265,6 +265,10 @@
       set_fact: VM_targets={{ VM_hosts | filter_vm_targets(topology['VMs'], VM_base) | sort }}
       when: topology['VMs'] is defined
 
+    - name: Set fallback default value for VM_targets
+      set_fact: VM_targets={{ [] }}
+      when: VM_targets is not defined
+
     - name: Set vm configuration properties when configuration is defined
       set_fact: vm_properties="{{ configuration | expand_properties(configuration_properties) }}"
       when: configuration is defined