Compiling and Running Applications

Scenario

IoTDB applications can run in a Linux environment where the Flink client is installed and in an environment where the Flink web UI is installed. After the application code is developed, you can upload the JAR file to the prepared environment.

Prerequisites

• The Flink component has been installed in the cluster and the FlinkServer instance has been added.
• The cluster client that contains the Flink service has been installed, for example, in the /opt/client directory.
• If the host where the client is installed is not a node in the cluster, the mapping between the host name and the IP address must be set in the hosts file on the node where the client is located. The host names and IP addresses must be mapped one by one.

Procedure

1. Build a JAR file.
   • In IntelliJ IDEA, configure Artifacts of the project before generating a JAR file.
     1. On the IDEA homepage, choose File > Project Structures... to go to the Project Structure page.
     2. On the Project Structure page, select Artifacts, click +, and select From modules with dependencies....
        Figure 1 Adding Artifacts
        
     3. Select extract to the target JAR and click OK.

        

     4. Set the name, type, and output path of the JAR file based on the site requirements.

        To avoid JAR file conflicts caused by unnecessary JAR files, you only need to load the following basic JAR files related to IoTDB:

        • flink-iotdb-connector-*
        • flink-tsfile-connector-*
        • iotdb-session-*
        • iotdb-thrift-*
        • service-rpc-*
        • tsfile-*

        Click OK.

        

     5. On the IDEA home page, choose Build > Build Artifacts.... On the Build Artifact page that is displayed, choose Action > Build.

        

        

     6. After the build is successful, the message "Build completed successfully" is displayed in the lower right corner, and the corresponding JAR file is generated in the Output Directory directory.

2. (Scenario 1) Run a Flink job on the Flink web UI.
   1. Log in to FusionInsight Manager of the cluster as a user who has the FlinkServer web UI management permission, choose Cluster > Services > Flink, and click the hyperlink next to Flink WebUI on the dashboard page to go to the FlinkServer web UI.
   2. On the FusionInsight Flink web UI, choose Job Management > Create Job to create a job.

      

   3. Set Type to Flink Jar, enter the name of the job to be created, select a task type, and click OK.

      

   4. Upload the JAR file generated in 1, set Main Class to Specify, enter the class to be executed in Class Parameter, and click Submit.

      For example, set Type to com.huawei.bigdata.iotdb.FlinkIoTDBSink (development program that executes FlinkIoTDBSink) or com.huawei.bigdata.iotdb.FlinkIoTDBSource (development program that executes FlinkIoTDBSource).

      

3. (Scenario 2) Submit a Flink job on the Flink client in the Linux environment.
   1. Log in to the MRS client as a client installation user.
   2. Run the following command to initialize environment variables:

      source /opt/client/bigdata_env

   3. If Kerberos authentication is enabled for the cluster, perform 3.d to 3.k. If Kerberos authentication is disabled for the cluster, skip these steps.
   4. Prepare a user for submitting Flink jobs.

      For details, see Preparing the Developer Account.

   5. Log in to Manager using the created user, choose System > Permission > User. Locate the row that contains the new user and choose More > Download Authentication Credential in the Operation column.
   6. Decompress the downloaded authentication credential package and copy the user.keytab file to the client node, for example, to the /opt/client/Flink/flink/conf directory on the client node.
   7. In security mode, append the service IP address of the node where the client is installed and floating IP address of Manager to the jobmanager.web.allow-access-address configuration item in the /opt/client/Flink/flink/conf/flink-conf.yaml file. Use commas (,) to separate IP addresses.
   8. Run the following commands to configure security authentication by adding the keytab path and username to the /opt/client/Flink/flink/conf/flink-conf.yaml configuration file.

      security.kerberos.login.keytab: <user.keytab file path>
      security.kerberos.login.principal: <Username>

      Example:

      security.kerberos.login.keytab: /opt/client/Flink/flink/conf/user.keytab
      security.kerberos.login.principal: test

   9. In the bin directory on the Flink client, run the following command to perform security hardening. For details, see Authentication and Encryption.

      sh generate_keystore.sh

      After the script is executed, enter a password for submitting jobs. Then, the value of SSL in /opt/client/Flink/flink/conf/flink-conf.yaml is automatically replaced.

      

      • In Authentication and Encryption, the generated flink.keystore, flink.truststore, and security.cookie are automatically filled in the corresponding configuration items in flink-conf.yaml.
      • The values of security.ssl.key-password, security.ssl.keystore-password, and security.ssl.truststore-password must be obtained using the Manager plaintext encryption API by running the following command:

        curl -k -i -u <user name>:<password> -X POST -HContent-type:application/json -d '{"plainText":"<password>"}' 'https://x.x.x.x:28443/web/api/v2/tools/encrypt'; in the preceding command, <password> must be the same as the password used for issuing the certificate, and x.x.x.x indicates the floating IP address of Manager in the cluster.

   10. Configure paths for the flink.keystore and flink.truststore files.
       • Absolute path: After the script is executed, the flink.keystore and flink.truststore file paths are automatically set to absolute paths in the flink-conf.yaml file. In this case, you need to place the flink.keystore and flink.truststore files in the conf directory to the absolute paths of the Flink client and each Yarn node in the cluster, respectively.
       • Relative path: Perform the following operations to set the flink.keystore and flink.truststore files to relative paths:
         1. In the /opt/client/Flink/flink/conf/ directory, create a directory, for example, ssl.

            cd /opt/client/Flink/flink/conf

            mkdir ssl

         2. Move the flink.keystore and flink.truststore files to the new folder.

            mv flink.keystore flink.truststore ssl/

         3. Change the values of the following parameters to relative paths in the flink-conf.yaml file:

            security.ssl.keystore: ssl/flink.keystore
            security.ssl.truststore: ssl/flink.truststore

   11. Add the IP addresses of the nodes where the clients are located to the following configuration items in the flink-conf.yaml file. Use commas (,) to separate IP addresses.

       web.access-control-allow-origin: xx.xx.xxx.xxx
       jobmanager.web.allow-access-address: xx.xx.xxx.xxx

   12. Upload the JAR file generated in 1 to the Flink client node, for example, /opt/client/Flink/flink, and submit the job.
       

       To submit or run jobs on Flink, the user must have the following permissions:

       • If Ranger authentication is enabled, the current user must belong to the hadoop group or the user has been granted the /flink read and write permissions in Ranger.
       • If Ranger authentication is disabled, the current user must belong to the hadoop group.
       • If the flink.keystore and flink.truststore files are stored in the absolute path:

         Run the following commands to start a session and submit a job in the session: com.huawei.bigdata.iotdb.FlinkIoTDBSink is the application in FlinkIoTDBSink.

         yarn-session.sh -nm "session-name"

         flink run --class com.huawei.bigdata.iotdb.FlinkIoTDBSink /opt/client/Flink/flink/flink-example.jar

       • If the flink.keystore and flink.truststore files are stored in the relative path:

         In the same directory of SSL, run the following commands to start a session and submit a job in the session. The SSL directory is a relative path. For example, if the SSL directory is /opt/client/Flink/flink/conf/, then run the following commands in this directory.

         com.huawei.bigdata.iotdb.FlinkIoTDBSink is the application in FlinkIoTDBSink.

         yarn-session.sh -t ssl/ -nm "session-name"

         flink run --class com.huawei.bigdata.iotdb.FlinkIoTDBSink /opt/client/Flink/flink/flink-example.jar