MRS MapReduce
Functions
The MRS MapReduce node is used to execute a predefined MapReduce program on MRS.
MapReduce is a programming model used for parallel computation of large-scale data sets (larger than 1 TB). Data computed by MapReduce comes from multiple data sources, mostly HDFS. MapReduce uses the high throughput performance of HDFS to read a large amount of data for computing and stores the processed data in HDFS.
Parameters
Table 1 and Table 2 describe the parameters of the MRS MapReduce node.
Parameter |
Mandatory |
Description |
---|---|---|
Node Name |
Yes |
Name of a node. The name must contain 1 to 128 characters, including only letters, numbers, underscores (_), hyphens (-), slashes (/), less-than signs (<), and greater-than signs (>). |
MRS Cluster Name |
Yes |
Name of the MRS cluster.
To create an MRS cluster, use either of the following methods:
|
MapReduce Job Name |
Yes |
MRS job name. It can contain a maximum of 64 characters. Only letters, digits, hyphens (-), and underscores (_) are allowed.
NOTE:
The job name cannot contain Chinese characters or more than 64 characters. If the job name does not meet requirements, the MRS job will fail to be submitted. |
JAR Package |
Yes |
Select a JAR package. Before selecting a JAR package, upload the JAR package to the OBS bucket, create a resource on the Manage Resource page, and add the JAR package to the resource management list. For details, see Creating a Resource.
NOTE:
If you configured an MRS tenant plane connection and selected keytab for MRS Authentication Type in Management Center, you cannot select an OBS JAR package. DataArts Studio and MRS are not connected to the same OBS. MRS cannot identify the OBS domain name transferred by DataArts Studio. As a result, an error message is displayed, indicating that the domain name cannot be accessed. |
JAR File Parameters |
No |
Parameters of the JAR package. You can set JAR package parameters as required. |
Input Data Path |
No |
Path where the input data is stored |
Output Data Path |
No |
Path where the output data is to be stored |
Parameter |
Mandatory |
Description |
---|---|---|
Node Status Polling Interval (s) |
Yes |
How often the system check completeness of the node. The value ranges from 1 to 60 seconds. |
Max. Node Execution Duration |
Yes |
Execution timeout interval for the node. If retry is configured and the execution is not complete within the timeout interval, the node will be executed again. |
Retry upon Failure |
Yes |
Whether to re-execute a node if it fails to be executed. Possible values:
|
Policy for Handling Subsequent Nodes If the Current Node Fails |
Yes |
Operation that will be performed if the node fails to be executed. Possible values:
|
Enable Dry Run |
No |
If you select this option, the node will not be executed, and a success message will be returned. |
Task Groups |
No |
Select a task group. If you select a task group, you can control the maximum number of concurrent nodes in the task group in a fine-grained manner in scenarios where a job contains multiple nodes, a data patching task is ongoing, or a job is rerunning. |
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