Creating a Flink Jar Job

Prerequisites

• When you use a Flink Jar job to access other external data sources, such as OpenTSDB, HBase, Kafka, GaussDB(DWS), RDS, CSS, CloudTable, DCS Redis, and DDS, you need to create a datasource connection to connect the job running queue to the external data source.
  • For details about the external data sources that can be accessed by Flink jobs, see Cross-Source Analysis Development Methods.
  • For details about how to create a datasource connection, see Enhanced Datasource Connections.

    On the Resources > Queue Management page, locate the queue you have created, click More in the Operation column, and select Test Address Connectivity to check if the network connection between the queue and the data source is normal. For details, see Testing Address Connectivity.

• When running a Flink Jar job, you need to build the secondary development application code into a Jar package and upload the JAR package to the created OBS bucket. Choose Data Management > Package Management to create a package. For details, see Creating a Package.
  

  DLI does not support the download function. If you need to modify the uploaded data file, please edit the local file and upload it again.

• Flink dependencies have been built in the DLI server and security hardening has been performed based on the open-source community version. To avoid dependency package compatibility issues or log output and dump issues, be careful to exclude the following files when packaging:
  • Built-in dependencies (or set the package dependency scope to provided in Maven or SBT)
  • Log configuration files (example, log4j.properties/logback.xml)
  • JAR package for log output implementation (example, log4j).

Precautions

Before creating jobs and submitting tasks, you are advised to enable CTS to record operations associated with DLI for later query, audit, and backtrack operations. To view the DLI operations that can be recorded by CTS, see DLI Operations That Can Be Recorded by CTS.

For details about how to enable CTS and view trace details, see the Cloud Trace Service Getting Started.

Creating a Flink Jar Job

1. In the left navigation pane of the DLI management console, choose Job Management > Flink Jobs. The Flink Jobs page is displayed.
2. In the upper right corner of the Flink Jobs page, click Create Job.

3. Specify job parameters.

   Table 1 Job configuration information

   Parameter	Description
   Type	Select Flink Jar.
   Name	Job name. Enter 1 to 57 characters. Only letters, numbers, hyphens (-), and underscores (_) are allowed. NOTE: The job name must be globally unique.
   Description	Description of a job. It can be up to 512 characters long.
   Tags	Tags used to identify cloud resources. A tag includes the tag key and tag value. If you want to use the same tag to identify multiple cloud resources, that is, to select the same tag from the drop-down list box for all services, you are advised to create predefined tags on the Tag Management Service (TMS). For details, see Tag Management Service User Guide. NOTE: A maximum of 20 tags can be added. Only one tag value can be added to a tag key. The key name in each resource must be unique. Tag key: Enter a tag key name in the text box. NOTE: A tag key can contain a maximum of 128 characters. Only letters, numbers, spaces, and special characters (_.:=+-@) are allowed, but the value cannot start or end with a space or start with _sys_. Tag value: Enter a tag value in the text box. NOTE: A tag value can contain a maximum of 255 characters. Only letters, numbers, spaces, and special characters (_.:=+-@) are allowed. The value cannot start or end with a space.

4. Click OK to enter the editing page.
5. Select a queue.
6. Configuring Flink Jar Job parameters

   Table 2 Parameters

   Parameter	Description
   Queue	Select a queue where you want to run your job.
   Application	Select the custom package that you have uploaded to the OBS bucket.
   Main Class	The name of the JAR package to be loaded, for example, KafkaMessageStreaming. Default: Specified based on the Manifest file in the JAR package. Manually assign: You must enter the class name and confirm the class arguments (separated by spaces). NOTE: When a class belongs to a package, the main class path must contain the complete package path, for example, packagePath.KafkaMessageStreaming.
   Class Arguments	List of arguments of a specified class. The arguments are separated by spaces. Flink parameters support replacement of non-sensitive global variables. For example, if you add the global variable windowsize in Global Configuration > Global Variables, you can add the -windowsSize {{windowsize}} parameter for the Flink Jar job.
   JAR Package Dependencies	Select a user-defined package dependency. The dependent program packages are stored in the classpath directory of the cluster. Before selecting a JAR file to be inserted, upload the corresponding JAR file to the OBS bucket and choose Data Management > Package Management to create a package. Select JAR as the package type. For details, see Creating a Package. For details about built-in dependency packages, see Built-in Dependencies.
   Other Dependencies	User-defined dependency files. Other dependency files need to be referenced in the code. Before selecting a dependency file, upload the file to the OBS bucket and choose Data Management > Package Management to create a package. The package type is not limited. For details, see Creating a Package. You can add the following command to the application to access the corresponding dependency file. In the command, fileName indicates the name of the file to be accessed, and ClassName indicates the name of the class that needs to access the file. ClassName.class.getClassLoader().getResource("userData/fileName")
   Flink Version	Before selecting a Flink version, you need to select the queue to which the Flink version belongs. Currently, versions 1.10, 1.11, and 1.12 are supported. NOTE: You are not advised to use Spark/Flink engines of different versions for a long time. Doing so can lead to code incompatibility, which can negatively impact job execution efficiency. Doing so may result in job execution failures due to conflicts in dependencies. Jobs rely on specific versions of libraries or components.
   Agency	If you choose Flink 1.15 to execute your job, you can create a custom agency to allow DLI to access other services.
   Runtime Configuration	User-defined optimization parameters. The parameter format is key=value. Flink optimization parameters support replacement non-sensitive global variable. For example, if you create global variable phase in Global Configuration > Global Variables, optimization parameter table.optimizer.agg-phase.strategy={{phase}} can be added to the Flink Jar job.

7. Configure job parameters.

   Table 3 Parameters

   Parameter	Description
   CUs	One CU consists of one vCPU and 4 GB of memory. The number of CUs ranges from 2 to 10000.
   Job Manager CUs	Number of CUs allowed for the job manager. The value ranges from 1 to 4. The default value is 1.
   Parallelism	Maximum number of parallel operators in a job. The value ranges from 1 to 10000. NOTE: The value must be less than or equal to four times the number of compute units (CUs minus the number of job manager CUs). You are advised to set this parameter to a value greater than that configured in the code. Otherwise, job submission may fail.
   Task Manager Config	Whether Task Manager resource parameters are set If this option is selected, you need to set the following parameters: CU(s) per TM: Number of resources occupied by each Task Manager. Slot(s) per TM: Number of slots contained in each Task Manager.
   Save Job Log	Whether to save the job running logs to the OBS bucket. CAUTION: You are advised to select this parameter. Otherwise, no run log is generated after the job is executed. If the job is abnormal, the run log cannot be obtained for fault locating. If this option is selected, you need to set the following parameters: OBS Bucket: Select an OBS bucket to store job logs. If the selected OBS bucket is not authorized, click Authorize.
   Alarm on Job Exception	Whether to notify users of any job exceptions, such as running exceptions or arrears, via SMS or email. If this option is selected, you need to set the following parameters: SMN Topic Select a custom SMN topic. For details about how to customize SMN topics, see Creating a Topic in the Simple Message Notification User Guide.
   Auto Restart upon Exception	Whether automatic restart is enabled. If enabled, jobs will be automatically restarted and restored when exceptions occur. If this option is selected, you need to set the following parameters: Max. Retry Attempts: maximum number of retries upon an exception. The unit is times/hour. Unlimited: The number of retries is unlimited. Limited: The number of retries is user-defined. Restore Job from Checkpoint: Restore the job from the saved checkpoint. If you select this parameter, you also need to set Checkpoint Path. Checkpoint Path: Select a path for storing checkpoints. This path must match that configured in the application package. Each job must have a unique checkpoint path, or, you will not be able to obtain the checkpoint.

8. Click Save on the upper right of the page.
9. Click Start on the upper right side of the page. On the displayed Start Flink Job page, confirm the job specifications and the price, and click Start Now to start the job.

   After the job is started, the system automatically switches to the Flink Jobs page, and the created job is displayed in the job list. You can view the job status in the Status column. Once a job is successfully submitted, its status changes from Submitting to Running. After the execution is complete, the status changes to Completed.

   If the job status is Submission failed or Running exception, the job fails to submit or run. In this case, you can hover over the status icon in the Status column of the job list to view the error details. You can click to copy these details. Rectify the fault based on the error information and resubmit the job.

   

   Other available buttons are as follows:

   Save As: Save the created job as a new job.