diff --git a/defaults/main.yml b/defaults/main.yml
index aea087d..2f53b96 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -26,6 +26,12 @@ mistral_system_user_home: /var/lib/mistral
 # Distribution deployment
 mistral_package_state: latest
 
+# This variable is used by the repo_build process to determine
+# which host group to check for members of before building the
+# pip packages required by this role. The value is picked up
+# by the py_pkgs lookup.
+mistral_role_project_group: mistral_all
+
 # Source package builds
 mistral_developer_mode: false
 mistral_git_repo: https://git.openstack.org/openstack/mistral
@@ -154,4 +160,4 @@ mistral_service_publicurl: "{{ mistral_service_publicuri_proto }}://{{ external_
 mistral_service_internaluri_proto: "{{ openstack_service_internaluri_proto | default(mistral_service_proto) }}"
 mistral_service_internalurl: "{{ mistral_service_internaluri_proto }}://{{ internal_lb_vip_address }}:{{ mistral_service_port }}/v2"
 mistral_service_adminuri_proto: "{{ openstack_service_adminuri_proto | default(mistral_service_proto) }}"
-mistral_service_adminurl: "{{ mistral_service_adminuri_proto }}://{{ internal_lb_vip_address }}:{{ mistral_service_port }}/v2"
\ No newline at end of file
+mistral_service_adminurl: "{{ mistral_service_adminuri_proto }}://{{ internal_lb_vip_address }}:{{ mistral_service_port }}/v2"