Typical Scenario: Importing Data from HBase to HDFS or OBS

Scenario

This section describes how to use Loader to export data from HBase to HDFS or OBS.

Prerequisites

• You have obtained the service username and password for creating a Loader job.
• You have had the permission to access the HDFS or OBS directories and data involved in job execution.
• You have had the permission to access the HBase tables or phoenix tables that are used during job execution.
• No disk space alarm is reported, and the available disk space is sufficient for importing and exporting data.
• If a configured task requires the Yarn queue function, the user must be authorized with related Yarn queue permission.
• The user who configures a task must obtain execution permission on the task and obtain usage permission on the related connection of the task.

Procedure

Configure basic job information.

1. Access the Loader web UI.
   1. Log in to FusionInsight Manager.
   2. Choose Cluster > Services > Loader.
   3. Click LoaderServer(Node name, Active). The Loader web UI is displayed.
      Figure 1 Loader web UI
      

2. Click New Job. Configure basic job parameters on the Basic Information page displayed.
   Figure 2 Basic Information page
   
   1. Enter a job name in Name.
   2. Set Type to Export.
   3. Set Group to the group to which the job belongs. There is no group created by default. Click Add, enter the group name, and click OK.
   4. Set Queue to the Yarn queue that executes the job. The default value is root.default.
   5. Set Priority to the priority of the Yarn queue that executes the job. The default value is NORMAL. The options are VERY_LOW, LOW, NORMAL, HIGH, and VERY_HIGH.

3. In the Connection area, click Add to create a connection, set Connector to hdfs-connector, set connection parameters, and click Test to verify whether the connection is available. When "Test Success" is displayed, click OK.

Configure data source information.

4. Click Next. On the displayed From page, set Source type to HBASE.

   Table 1 Parameter description

   Parameter	Description	Example Value
   HBase instance	Specifies the HBase service instance that Loader selects from all available HBase service instances in the cluster. If the selected HBase service instance is not added to the cluster, the HBase job cannot be run properly.	HBase
   Quantity	Number of Maps that are started at the same time in a MapReduce task of a data configuration operation. The value must be less than or equal to 3000.	20

Configure data transformation.

5. Click Next. On the displayed Transform page, set the transformation operations in the data transformation process. For details about how to select operators and set parameters, see Operator Help and Table 2.

   Table 2 Input and output parameters of the operator

   Input Type	Output Type
   HBase Input	File Output

   In input, drag HBase Input to the grid. In output, drag File Output to the grid. Use an arrow to connect HBase Input to File Output.

Set data storage information and execute the job.

6. Click Next. On the displayed To page, set the data storage mode.

   Table 3 Parameter description

   Parameter	Description	Example Value
   Output path	Specifies the output directory or file name of the export file in the HDFS or OBS. NOTE: You can use macros to define path parameters. For details, see Using Macro Definitions in Configuration Items.	/user/test
   File Format	Specifies the file export type. TEXT_FILE: imports a text file and saves it as a text file. SEQUENCE_FILE: imports a text file and saves it as a sequence file. BINARY_FILE: imports files of any format using binary streams.	TEXT_FILE
   Compression codec	Specifies the compression format of files exported to HDFS or OBS. Select a format from the drop-down list. If you select NONE or do not set this parameter, data is not compressed.	NONE

7. Click Save and Run to save and run the job.

View the job execution result.

8. Go to the Loader web UI. When Status is Succeeded, the job is complete.
   Figure 3 Viewing job details