diff --git a/jjb/cloud-infra/promote-onap.sh b/jjb/cloud-infra/promote-onap.sh
index 345754b..9de2480 100644
--- a/jjb/cloud-infra/promote-onap.sh
+++ b/jjb/cloud-infra/promote-onap.sh
@@ -27,7 +27,10 @@
 cd /tmp && /bin/rm -rf $WORKSPACE
 git clone -q https://gerrit.nordix.org/infra/swconfig.git $WORKSPACE
 cd $WORKSPACE/scenarios/onap-nofeature-noha/kubespray/playbooks
+# avoid PS1: unbound variable issue
+set +u
 source /opt/engine/.venv/bin/activate
+set -u
 ansible-playbook -i /tmp/inventory.ini promote.yml
 echo "-------------------------------------------------------------------------"
 echo "Info: Promotion done!"