If mongod can't start up successfully for some reason, smoke.py will just complain "timed out starting mongod" and exit. However, smoke.py also swallows all the logging output from the mongod, so there's no way of seeing why it failed to start up (could be caused by a crash, machine environment, invalid command line args, etc.).

smoke.py should at the very least show the mongod's output so that the reason for the startup failure can be debugged.