Submitting a DistCp Job

Scenario

This section describes how to submit a DistCp job using the Oozie client.

You are advised to download the latest client.

Prerequisites

• The HDFS and Oozie components and clients have been installed and are running properly.

  If the current client is an earlier version, you need to download and install the client again.

• You have created or obtained the human-machine account and password for accessing the Oozie service.
  

  • This user must belong to the hadoop, supergroup, and hive groups and be assigned with the Oozie role operation permission. If the multi-instance function is enabled for Hive, the user must belong to a specific Hive instance group, for example, hive3.
  • This user must also be assigned the manager_viewer role at least.

Procedure

1. Log in to the node where the Oozie client is installed as the client installation user .
2. Run the following command to obtain the installation environment. /opt/client/ is an example client installation path.

   source /opt/client/bigdata_env

3. Check the cluster authentication mode.
   • If the cluster is in security mode, run the kinit command to authenticate users.

     For example, the oozieuser user is authenticated using the following command:

     kinit oozieuser

   • If the cluster is in normal mode, go to 4.

4. Run the following command to go to the example directory:

   cd /opt/client/Oozie/oozie-client-*/examples/apps/distcp/

   Table 1 lists the files that you need to pay attention to in the directory.

   Table 1 File description

   File	Description
   job.properties	Parameter definition file of a workflow
   workflow.xml	Rule definition file of a workflow

5. Run the following command to edit the job.properties file:

   vi job.properties

   Perform the following modifications:

   Change the value of userName to the name of the human-machine user who submits the job, for example, userName=oozieuser.

6. Whether DistCp is not deployed across security clusters.
   • If yes, go to 7.
   • If no, go to 9.

7. Establish cross-Manager mutual trust between two clusters.
8. Run the following commands to back up and modify the workflow.xml file:

   cp workflow.xml workflow.xml.bak

   vi workflow.xml

   Modify the following content:

   <workflow-app xmlns="uri:oozie:workflow:1.0" name="distcp-wf">
       <start to="distcp-node"/>
       <action name="distcp-node">
           <distcp xmlns="uri:oozie:distcp-action:1.0">
               <resource-manager>${resourceManager}</resource-manager>
               <name-node>${nameNode}</name-node>
               <prepare>
                   <delete path="hdfs://target_ip:target_port/user/${userName}/${examplesRoot}/output-data/${outputDir}"/>
               </prepare>
               <configuration>
                   <property>
                       <name>mapred.job.queue.name</name>
                       <value>${queueName}</value>
                   </property>
                   <property>
                       <name>oozie.launcher.mapreduce.job.hdfs-servers</name>
                       <value>hdfs://source_ip:source_port,hdfs://target_ip:target_port</value>
                   </property>
               </configuration>
               <arg>${nameNode}/user/${userName}/${examplesRoot}/input-data/text/data.txt</arg>
               <arg>hdfs://target_ip:target_port/user/${userName}/${examplesRoot}/output-data/${outputDir}/data.txt</arg>
               </distcp>
           <ok to="end"/>
           <error to="fail"/>
       </action>
       <kill name="fail">
           <message>DistCP failed, error message[${wf:errorMessage(wf:lastErrorNode())}]</message>
       </kill>
       <end name="end"/>
   </workflow-app>

   target_ip:target_port is the HDFS active NameNode address of the other trusted cluster, for example, 10.10.10.233:25000.

   source_ip:source_port indicates the HDFS active NameNode address of the source cluster, for example, 10.10.10.223:25000.

   Change the two IP addresses and port numbers based on the site requirements.

9. Run the oozie job command to run the workflow file:

   oozie job -oozie https://Host name of the Oozie role:21003/oozie/ -config job.properties -run

   

   • The command parameters are described as follows:

     -oozie URL of the Oozie server that executes a job

     -config Workflow property file

     -run Executing a workflow

   • If a job ID, for example, job: 0000021-140222101051722-oozie-omm-W, is displayed after the workflow file is executed, the job is successfully submitted. You can view the execution results on the Oozie management page.

     Log in to the Oozie web UI at https://IP address of the Oozie role:21003/oozie as user oozieuser.

     On the Oozie web UI, you can view the submitted workflow information based on the job ID in the table on the page.