When a Mistral workflow fails during the overcloud deployment, the error is reported to the operator like this: overcloud.AllNodesDeploySteps.WorkflowTasks_Step5_Execution: resource_type: OS::TripleO::WorkflowSteps physical_resource_id: 3a0b5696-8f20-4d05-9222-0b9a7d763fc6 status: CREATE_FAILED status_reason: | resources.WorkflowTasks_Step5_Execution: ERROR Heat Stack update failed. Heat Stack update failed. This doesn't provide the operator with any information about the cause of the failure. This is generally reported in mistral logs (engine.log, execution.log). These failures should be collected by the mistral api, if they're not already, and then communicated to the operator.
Thomas, you may have the unique skills to improve the error path feedback from heat->mistral->user, let us know if you can take this bug.
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/RHBA-2019:0563