diff --git a/roles/undercloud-deploy/templates/hieradata-overrides-t-h-t-undercloud.yaml.j2 b/roles/undercloud-deploy/templates/hieradata-overrides-t-h-t-undercloud.yaml.j2
index 02dda1405..3b5fe8662 100644
--- a/roles/undercloud-deploy/templates/hieradata-overrides-t-h-t-undercloud.yaml.j2
+++ b/roles/undercloud-deploy/templates/hieradata-overrides-t-h-t-undercloud.yaml.j2
@@ -1,5 +1,10 @@
 parameter_defaults:
   UndercloudExtraConfig:
+    ironic::config::ironic_config:
+      disk_utils/image_convert_memory_limit:
+        value:
+          2048
+
     # Ironic defaults to using `qemu:///system`.  When running libvirtd
     # unprivileged we need to use `qemu:///session`.  This allows us to pass
     # the value of libvirt_uri into /etc/ironic/ironic.conf.