Flink provides a web interface to upload jobs, inspect their execution plans, and execute them. The interface is a great tool to showcase programs, debug execution plans, or demonstrate the system as a whole.
Start the web interface by executing:
./bin/start-webclient.sh
and stop it by calling:
./bin/stop-webclient.sh
The web interface runs on port 8080 by default. To specify a custom port set the webclient.port property in the ./conf/flink.yaml configuration file. Jobs are submitted to the JobManager specified by jobmanager.rpc.address and jobmanager.rpc.port. Please consult the [configuration]({{ site.baseurl }}/setup/config.html#webclient) page for details and further configuration options.
The web interface provides two views:
The web interface can also handle multiple Flink jobs within a single jar file. To use this feature, package all required class files of all jobs into a single jar and specify the entry classes for each job as comma-separated-values in program-class argument within the jar‘s manifest file. The job view displays each entry class and you can pick any of them to preview the plan and/or submit the job to the JobManager. In case the jar’s manifest file does not specify any entry class, you can specify it in the options field as:
-c <assemblerClass>
It is also possible to set the default parallelism for the execution in options field as:
-p <dop>
Furthermore, for each entry class implementing ProgramDescription interface, the provided description is shown as tooltip for the job (see {% gh_link flink-examples/flink-java-examples/src/main/java/org/apache/flink/examples/java/wordcount/WordCountMeta.java “WordCountMeta example” %}).
To submit the job for execution, click again on the <em>"Run Job"</em> button in the bottom right.
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<a data-lightbox="compiler" href="{{ site.baseurl }}/page/img/webclient_plan_view.png" data-lightbox="example-1"><img class="img-responsive" src="{{ site.baseurl }}/page/img/webclient_plan_view.png" /></a>
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