Interconnecting FlinkServer with Kafka

Scenario

This section describes the data definition language (DDL) of Kafka as a source or sink table, as well as the WITH parameters and example code for creating a table, and provides guidance on how to perform operations on the FlinkServer job management page.

If your Kafka cluster is in security mode, the following example SQL statements can be used.

Prerequisites

• The HDFS, Yarn, Kafka, and Flink services have been installed in a cluster.
• The client that contains the Kafka service has been installed, for example, in the /opt/Bigdata/client directory.
• You have created a user with FlinkServer Admin Privilege, for example, flink_admin, to access the Flink web UI. For details, see Authentication Based on Users and Roles.

Procedure

1. Log in to Manager as user flink_admin and choose Cluster > Services > Flink. In the Basic Information area, click the link on the right of Flink WebUI to access the Flink web UI.
2. Create a Flink SQL job by referring to Creating a Job. On the job development page, configure the job parameters as follows and start the job.
   Select Enable CheckPoint in Running Parameter and set Time Interval (ms) to 60000.

   CREATE TABLE KafkaSource (
     `user_id` VARCHAR,
     `user_name` VARCHAR,
     `age` INT
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'test_source',
     'properties.bootstrap.servers' = 'IP address of the Kafka broker instance:Kafka port number',
     'properties.group.id' = 'testGroup',
     'scan.startup.mode' = 'latest-offset',
     'format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',
     'properties.security.protocol' = 'SASL_PLAINTEXT',
     'properties.kerberos.domain.name' = 'hadoop.System domain name'
   );
   CREATE TABLE KafkaSink(
     `user_id` VARCHAR,
     `user_name` VARCHAR,
     `age` INT
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'test_sink',
     'properties.bootstrap.servers' = 'IP address of the Kafka broker instance:Kafka port number',
     'scan.startup.mode' = 'latest-offset',
     'value.format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',
     'properties.security.protocol' = 'SASL_PLAINTEXT',
     'properties.kerberos.domain.name' = 'hadoop.System domain name'
   );
   Insert into
     KafkaSink
   select
     *
   from
     KafkaSource;

   

   Kafka port number

   • In security mode, the port number is the value of sasl.port (21007 by default).
   • In non-security mode, the port is the value of port (9092 by default). If the port number is set to 9092, set allow.everyone.if.no.acl.found to true. The procedure is as follows:

     Log in to FusionInsight Manager and choose Cluster > Services > Kafka. On the displayed page, click Configurations and then All Configurations, search for allow.everyone.if.no.acl.found, set its value to true, and click Save.

3. On the job management page, check whether the job status is Running.
4. Execute the following commands to view the topic and write data to Kafka. For details, see Managing Messages in Kafka Topics.

   ./kafka-topics.sh --list --zookeeper IP address of the ZooKeeper quorumpeer instance:ZooKeeper port number/kafka

   sh kafka-console-producer.sh --broker-list IP address of the node where the Kafka instance locates:Kafka port number --topic Topic name --producer.config Client directory/Kafka/kafka/config/producer.properties

   For example, if the topic name is test_source, the script is sh kafka-console-producer.sh --broker-list IP address of the node where the Kafka instance locates:Kafka port number --topic test_source --producer.config /opt/Bigdata/client/Kafka/kafka/config/producer.properties.

   Enter the message content.

   1,clw,33

   Press Enter to send the message.

   

   • IP address of the ZooKeeper quorumpeer instance

     To obtain IP addresses of all ZooKeeper quorumpeer instances, log in to FusionInsight Manager and choose Cluster > Services > ZooKeeper. On the displayed page, click Instance and view the IP addresses of all the hosts where the quorumpeer instances locate.

   • Port number of the ZooKeeper client

     Log in to FusionInsight Manager and choose Cluster > Service > ZooKeeper. On the displayed page, click Configurations and check the value of clientPort. The default value is 24002.

5. Run the following commands to check whether data is written from the Kafka topic to the sink table:

   sh kafka-console-consumer.sh --topic Topic name --bootstrap-server IP address of the Kafka broker instance:Kafka port number --consumer.config /opt/Bigdata/client/Kafka/kafka/config/consumer.properties

WITH Parameters