Description of problem: If upgrade playbook is failing during gluster pod upgrade then we can not upgrade the OCS in next retries because at that time there is no heketi DC. During the next retry, the playbook will start upgrading the OCS, again from the beginning and eventually upgrade will fail at the step where playbook search for Heketi Pod and deletes the DC where it will not find any DC.
Upgrade playbook is in tech-preview state and will remain so. Due to resource constraints we will not be futher improving or enhancing the upgrade playbook.