[FLINK-21768] Optimize system.exit() logic of CliFrontend

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Component/s: Command Line Client
• Labels: pull-request-available
• Assignee: Junfan Zhang
• Reporter: Junfan Zhang
• Created: 13/Mar/21 12:37
• Updated: 22/Mar/21 10:22
• Resolved: 22/Mar/21 09:39

Description

Why

We encounter a problem when Oozie integerated with Flink Batch Action.
Oozie will use a launcher job to start Flink client used to submit Flink job to Hadoop Yarn.
And when Flink client finished , Oozie will get its exitCode to determine job submission status and then do some extra things.

So how Oozie catch System.exit()? It will implement JDK SecurityManager. (Oozie related code link).

Now when Flink Client finished successfully, it will call System.exit(0)(Flink related code link) method.
And then JVM will use LauncherSecurityManager(Oozie implemented) to handle System.exit(0) method and trigger LauncherSecurityManager.checkExit() method, and then will throw exception.
Finally Flink Client will catch its throwable and call System.exit(31)(related code link) method again. It will cause Oozie to misjudge the status of the Fllink job.

Actually it's a corner case. In most scenes, the situation I mentioned will not happen. But it's still necessary for us to optimize client exit logic.

Besides, i think the problem above may also exist in some other frameworks such as linkedin/azakaban and apache/airflow, which are using Flink client to submit batch job.

Flink related code:

    public static void main(final String[] args) {
        EnvironmentInformation.logEnvironmentInfo(LOG, "Command Line Client", args);

        // 1. find the configuration directory
        final String configurationDirectory = getConfigurationDirectoryFromEnv();

        // 2. load the global configuration
        final Configuration configuration =
                GlobalConfiguration.loadConfiguration(configurationDirectory);

        // 3. load the custom command lines
        final List<CustomCommandLine> customCommandLines =
                loadCustomCommandLines(configuration, configurationDirectory);

        try {
            final CliFrontend cli = new CliFrontend(configuration, customCommandLines);

            SecurityUtils.install(new SecurityConfiguration(cli.configuration));
            int retCode =
                    SecurityUtils.getInstalledContext().runSecured(() -> cli.parseAndRun(args));
            System.exit(retCode);
        } catch (Throwable t) {
            final Throwable strippedThrowable =
                    ExceptionUtils.stripException(t, UndeclaredThrowableException.class);
            LOG.error("Fatal error while running command line interface.", strippedThrowable);
            strippedThrowable.printStackTrace();
            System.exit(31);
        }
    }

Issue Links

• links to: GitHub Pull Request #15185