In TestGrantRevoke::test_role_update, one of the impala daemons is restarted. When the test finishes, it doesn't kill or wait for the restarted process. There are several problems of not doing so:
- When another custom cluster test attempts to kill the impala daemon, the impala daemon will become a zombie process. The PID won't go away until the py tests process exits. start-impala-cluster.py doesn't handle this case correctly and will time out. Fortunately, test_role_update is always the last test in custom cluster tests, so it doesn't break builds for now.
- It leaks PID and process information in the kernel as long as the py test process is running.