diff --git a/playbooks/legacy/oslo.versionedobjects-src-grenade-devstack-multinode/run.yaml b/playbooks/legacy/oslo.versionedobjects-src-grenade-devstack-multinode/run.yaml
index 8dece945..5a9d39ef 100644
--- a/playbooks/legacy/oslo.versionedobjects-src-grenade-devstack-multinode/run.yaml
+++ b/playbooks/legacy/oslo.versionedobjects-src-grenade-devstack-multinode/run.yaml
@@ -32,6 +32,7 @@
           export PYTHONUNBUFFERED=true
           export DEVSTACK_GATE_TEMPEST=1
           export DEVSTACK_GATE_GRENADE=pullup
+          export DEVSTACK_GATE_USE_PYTHON3=True
           export BRANCH_OVERRIDE=default
           if [ "$BRANCH_OVERRIDE" != "default" ] ; then
               export OVERRIDE_ZUUL_BRANCH=$BRANCH_OVERRIDE