Most exceptions - even unexpected exceptions - in Heat are caught and handled. For example, any exception that occurs while processing a resource operation will cause the resource to be placed in a FAILED state and will generate a ResourceFailure exception that is caught and handled appropriately. Most uncaught, unhandled exceptions (e.g. exceptions that occur before starting a stack operation) will bubble up to the user - the RPC handler will throw the exception, which will then be reported as the result of the RPC call by oslo.messaging. There is one exception: code at the start and end of a long-running stack operation that is executed in a separate greenthread (so that exceptions don't bubble up to a RPC response). While any exception that occurs here is a bug, it would be very helpful if we had better error reporting of such bugs when they do occur. Currently the backtrace is printed to stderr, which in many installations means /dev/null (on systems with systemd, it appears in the journald logs, so at least it's not completely lost). We should catch and log these exceptions with a big red ERROR.
I'd like this to be considered for being a blocker for 7.2 since exceptions being logged to the journal instead of heat-engine.log has been hindering our rhos-director 7.0->7.x update efforts.
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-2015:2680