diff --git a/playbooks/validate_hosts.yml b/playbooks/validate_hosts.yml
index c7618b9046..347f438fa4 100644
--- a/playbooks/validate_hosts.yml
+++ b/playbooks/validate_hosts.yml
@@ -111,6 +111,7 @@
           "Not enough memory to run {{ item }}. Only {{ ansible_memory_mb.nocache.free }}MB of free memory detected.
           Minimum memory required is {{ lookup('vars', 'required_total_memory_mb_' + item) }} MB, please add more memory to host
           or choose a different host to install {{ item }} to continue installation."
+      when: ('required_total_memory_mb_' + item) in vars
       tags:
         - validate_memory_usage
       loop: "{{group_names}}"