diff --git a/playbooks/legacy/grenade-devstack-barbican/run.yaml b/playbooks/legacy/grenade-devstack-barbican/run.yaml
index 8e889732b..0b4b8e4d1 100644
--- a/playbooks/legacy/grenade-devstack-barbican/run.yaml
+++ b/playbooks/legacy/grenade-devstack-barbican/run.yaml
@@ -40,6 +40,7 @@
           export DEVSTACK_GATE_TEMPEST=1
           export DEVSTACK_GATE_GRENADE=pullup
           export DEVSTACK_GATE_TEMPEST_REGEX=barbican
+          export DEVSTACK_GATE_USE_PYTHON3=True
 
           export BRANCH_OVERRIDE=default
           if [ "$BRANCH_OVERRIDE" != "default" ] ; then