Major Description
With MesosContainerizer, the sandbox is of type FileSystemImageSandbox and the health check is performed using a "mesos-containerizer launch" process, but there is actually a code bug in the way of getting the user under which to run the health check process:
health_check_user = (os.getusername() if self._nosetuid_health_checks else assigned_task.task.job.role)
If the Aurora scheduler is configured with `--nosetuid-health-checks` then "os.getusername()" is executed, but the python "os" module does not present a "getusername()" function.