Environments based on deployed servers (not using Nova+Ironic to manage bare metal) might not have heat-admin user present and ready for Mistral to ssh into. We need to accept --ssh-user parameter for the update/upgrade run commands.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2018:2086