diff --git a/zuul.d/base.yaml b/zuul.d/base.yaml
index 2d978c0..0140ad7 100644
--- a/zuul.d/base.yaml
+++ b/zuul.d/base.yaml
@@ -13,6 +13,12 @@
     roles: &base_roles
       - zuul: opendev.org/openstack/devstack
     vars: &base_vars
+      devstack_localrc:
+        IMAGE_URLS: http://download.cirros-cloud.net/0.6.2/cirros-0.6.2-x86_64-disk.img, http://download.cirros-cloud.net/0.6.1/cirros-0.6.1-x86_64-disk.img
+        # When DEFAULT_IMAGE_NAME is set and the image exists in glance,
+        # devstack sets both image_ref and image_ref_alt with same image
+        # which we don't want here.
+        DEFAULT_IMAGE_NAME: 'non-existent-image'
       devstack_services:
         tempest: true
       devstack_local_conf: