Creating a FlinkServer Job to Interconnect with JDBC

Scenario

FlinkServer can interconnect with JDBC. This topic uses FlinkServer and Kafka in security mode as an example to describe the DDL definition for JDBC MySQL source tables, sink tables, and dimension tables. This topic also explains the WITH parameters for creating a table and code examples. You will learn how to connect to JDBC on the FlinkServer job management page.

When "FlinkSQL" is displayed in the command output on the FlinkServer web UI in MRS 3.2.0 or later clusters, the password field in the SQL statement is left blank. Before you submit a job, manually enter the password.

Mapping between Flink SQL and JDBC data types

Prerequisites

JDBC Sink Table (MySQL as an Example)

1. Create an empty table for receiving data in a database, for example, MySQL database customer_t1.
2. Log in to Manager as user flinkuser and choose Cluster > Services > Flink. In the Basic Information area, click the link next to Flink WebUI to access the Flink web UI.
3. Create a Flink SQL job by referring to Creating a FlinkServer Job. On the job development page, configure the job parameters as follows and start the job.

   In Basic Parameter, select Enable CheckPoint, set Time Interval(ms) to 60000, and retain the default value for Mode.

   CREATE TABLE MyUserTable(
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32)
   ) WITH(
     'connector' = 'jdbc',
     'url' = 'jdbc:mysql://IP address of the MySQL server:MySQL server port/mysql',
     'table-name' = 'customer_t1',
     'username' ='MySQL database username',
     'password' ='Password of the MySQL database user'
   );
   CREATE TABLE KafkaSource (
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32)
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'customer_source',
     'properties.bootstrap.servers' = 'Service IP address of the Kafka Broker instance:Kafka port number',
     'properties.group.id' = 'testGroup',
     'scan.startup.mode' = 'latest-offset',
     'value.format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.security.protocol' = 'SASL_PLAINTEXT',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.kerberos.domain.name' = 'hadoop.System domain name'  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
   );
   Insert into
     MyUserTable
   select
     *
   from
     KafkaSource;

   

   • The IP address and port number of the Kafka broker instance are as follows:
     • To obtain the instance IP address, log in to FusionInsight Manager, choose Cluster > Services > Kafka, click Instance, and query the instance IP address on the instance list page.
     • If Kerberos authentication is enabled for the cluster (the cluster is in security mode), the Broker port number is the value of sasl.port. The default value is 21007.
     • If Kerberos authentication is disabled for the cluster (the cluster is in normal mode), the broker port number is the value of port. The default value is 9092. 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. Click Configurations then All Configurations. On the page that is displayed, search for allow.everyone.if.no.acl.found, set it to true, and click Save.

   • System domain name: To obtain the value, log in to FusionInsight Manager, choose System > Permission > Domain and Mutual Trust, and check the value of Local Domain.
   • properties.group.id indicates the Kafka user group ID. This parameter is mandatory when Kafka functions as the source.
   • properties.kerberos.domain.name: Set it to hadoop.System domain name. To obtain the actual domain name of the cluster, log in to FusionInsight Manager and choose System > Permission > Domain and Mutual Trust.

4. On the job management page, check whether the job status is Running.
5. 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 --bootstrap-server Service IP address of the Kafka Broker instance:Kafka port --command-config Client directory/Kafka/kafka/config/client.properties

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

   In this example, the topic name is customer_source.

   sh kafka-console-producer.sh --broker-list IP address of the node where the Kafka Broker instance is located:Kafka port --topic customer_source --producer.config /opt/client/Kafka/kafka/config/producer.properties

   Enter the message content.

   3,zhangsan
   4,wangwu
   8,zhaosi

   Press Enter to send the message.

6. Log in to the MySQL client and run the following statement to check whether the sink table received data:

   Select * from customer_t1;

JDBC Source Table (MySQL as an Example)

1. Log in to Manager as user flinkuser and choose Cluster > Services > Flink. In the Basic Information area, click the link next to Flink WebUI to access the Flink web UI.
2. Create a Flink SQL job by referring to Creating a FlinkServer Job. On the job development page, configure the job parameters as follows and start the job.

   In Basic Parameter, select Enable CheckPoint, set Time Interval(ms) to 5000, and retain the default value for Mode.

   CREATE TABLE MyUserTable(
     --MySQL source table
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32)
   ) WITH(
     'connector' = 'jdbc',
     'url' = 'jdbc:mysql://IP address of the MySQL server:MySQL server port/mysql',
     'table-name' = 'customer_t1',
     'username' ='MySQL database username',
     'password' ='Password of the MySQL database user'
   );
   CREATE TABLE KafkaSink (
     -- Kafka functions as a sink table.
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32)
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'customer_sink',
     'properties.bootstrap.servers' = 'Service IP address of the Kafka Broker instance:Kafka port number',
     'properties.group.id' = 'testGroup',
     'scan.startup.mode' = 'latest-offset',
     'value.format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.security.protocol' = 'SASL_PLAINTEXT',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.kerberos.domain.name' = 'hadoop.System domain name'  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
   );
   Insert into
     KafkaSink
   select
     *
   from
     MyUserTable;

   

   • The IP address and port number of the Kafka broker instance are as follows:
     • To obtain the instance IP address, log in to FusionInsight Manager, choose Cluster > Services > Kafka, click Instance, and query the instance IP address on the instance list page.
     • If Kerberos authentication is enabled for the cluster (the cluster is in security mode), the Broker port number is the value of sasl.port. The default value is 21007.
     • If Kerberos authentication is disabled for the cluster (the cluster is in normal mode), the broker port number is the value of port. The default value is 9092. 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. Click Configurations then All Configurations. On the page that is displayed, search for allow.everyone.if.no.acl.found, set it to true, and click Save.

   • System domain name: You can log in to FusionInsight Manager, choose System > Permission > Domain and Mutual Trust, and check the value of Local Domain.
   • properties.group.id indicates the Kafka user group ID. This parameter is mandatory when Kafka functions as the source.
   • properties.kerberos.domain.name: Set it to hadoop.System domain name. You can log in to FusionInsight Manager and choose System > Permission > Domain and Mutual Trust to view the actual domain name of the cluster.

3. On the job management page, check whether the job status is Running.
4. Obtain the required Kafka IP address and port by referring to Managing Messages in Kafka Topics, and run the following command to check whether data is written from the Kafka topic to the sink table:

   sh kafka-console-consumer.sh --topic customer_sink --bootstrap-server IP address of the node where the Kafka instance is deployed:Kafka port number --consumer.config /opt/client/Kafka/kafka/config/ consumer.properties

   

JDBC Dimension Table (MySQL as an Example)

kafkaSource is used as the fact table, customer_t2 is used as the dimension table, and the result is written to kafkaSink.

1. Create the dimension table customer_t2 on the MySQL client. An example of the table creation statement is as follows:

   CREATE TABLE customer_t2(
   c_customer_sk INTEGER PRIMARY KEY,
   c_customer_age INTEGER,
   c_customer_address VARCHAR(32)
   );
    
   INSERT INTO customer_t2 VALUES(1,18,'city a');
   INSERT INTO customer_t2 VALUES(2,14,'city b');
   INSERT INTO customer_t2 VALUES(3,16,'city c');
   INSERT INTO customer_t2 VALUES(4,24,'city d');
   INSERT INTO customer_t2 VALUES(5,32,'city e');
   INSERT INTO customer_t2 VALUES(6,27,'city f');
   INSERT INTO customer_t2 VALUES(7,41,'city a');
   INSERT INTO customer_t2 VALUES(8,35,'city h');
   INSERT INTO customer_t2 VALUES(9,16,'city j');

2. Log in to Manager as user flinkuser and choose Cluster > Services > Flink. In the Basic Information area, click the link next to Flink WebUI to access the Flink web UI.
3. Create a Flink SQL job by referring to Creating a FlinkServer Job. On the job development page, configure the job parameters as follows and start the job.

   In Basic Parameter, select Enable CheckPoint, set Time Interval(ms) to 5000, and retain the default value for Mode.

   CREATE TABLE KafkaSource (
     -- Kafka as a source table
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32),
     proctime as proctime()
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'customer_source',
     'properties.bootstrap.servers' = 'Service IP address of the Kafka Broker instance:Kafka port',
     'properties.group.id' = 'testGroup',
     'scan.startup.mode' = 'latest-offset',
     'value.format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.security.protocol' = 'SASL_PLAINTEXT',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.kerberos.domain.name' = 'hadoop.System domain name'  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
   );
   CREATE TABLE KafkaSink (
     -- Kafka sink table.
     c_customer_sk INTEGER,
     c_customer_name VARCHAR(32),
     c_customer_age INTEGER,
     c_customer_address VARCHAR(32)
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'customer_sink',
     'properties.bootstrap.servers' = 'Service IP address of the Kafka Broker instance:Kafka port',
     'properties.group.id' = 'testGroup',
     'scan.startup.mode' = 'latest-offset',
     'value.format' = 'csv',
     'properties.sasl.kerberos.service.name' = 'kafka',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.security.protocol' = 'SASL_PLAINTEXT',  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
     'properties.kerberos.domain.name' = 'hadoop.System domain name'  --Delete this parameter if the cluster where FlinkServer is deployed is in non-security mode.
   );
   CREATE TABLE MyUserTable (
     -- MySQL dimension table
     c_customer_sk INTEGER PRIMARY KEY NOT ENFORCED,
     c_customer_age INTEGER,
     c_customer_address VARCHAR(32)
   ) WITH (
     'connector' = 'jdbc',
     'url' = 'jdbc:mysql://IP address of the MySQL server:MySQL server port/mysql',
     'table-name' = 'customer_t2',
     'username' ='MySQL database username',
     'password' ='Password of the MySQL database user'
   );
   INSERT INTO
     KafkaSink
   SELECT
     t.c_customer_sk,
     t.c_customer_name,
     d.c_customer_age,
     d.c_customer_address
   FROM
     KafkaSource as t
     JOIN MyUserTable FOR SYSTEM_TIME AS OF t.proctime as d ON t.c_customer_sk = d.c_customer_sk;

   

   • The IP address and port number of the Kafka broker instance are as follows:
     • To obtain the instance IP address, log in to FusionInsight Manager, choose Cluster > Services > Kafka, click Instance, and query the instance IP address on the instance list page.
     • If Kerberos authentication is enabled for the cluster (the cluster is in security mode), the Broker port number is the value of sasl.port. The default value is 21007.
     • If Kerberos authentication is disabled for the cluster (the cluster is in normal mode), the broker port number is the value of port. The default value is 9092. 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. Click Configurations then All Configurations. On the page that is displayed, search for allow.everyone.if.no.acl.found, set it to true, and click Save.

   • System domain name: You can log in to FusionInsight Manager, choose System > Permission > Domain and Mutual Trust, and check the value of Local Domain.
   • properties.group.id indicates the Kafka user group ID. This parameter is mandatory when Kafka functions as the source.
   • properties.kerberos.domain.name: Set it to hadoop.System domain name. You can log in to FusionInsight Manager and choose System > Permission > Domain and Mutual Trust to view the actual domain name of the cluster.

4. Run the following command to check whether data is received in the sink table, that is, check whether data is properly written to the Kafka topic after 5 is performed. For details, see Managing Messages in Kafka Topics.

   sh kafka-console-consumer.sh --topic customer_sink --bootstrap-server IP address of the node where the Kafka instance is deployed:Kafka port number --consumer.config /opt/client/Kafka/kafka/config/ consumer.properties

5. View the topic and write data to the Kafka topic by referring to Managing Messages in Kafka Topics. After the data is written, view the execution result in the window in 4.

   ./kafka-topics.sh --list Service IP address of the Kafka Broker instance:Kafka port --command-config Client directory/Kafka/kafka/config/client.properties

   sh kafka-console-producer.sh --broker-list IP address of the node where Kafka Broker instances are deployed:Kafka port --topic Topic name --producer.config Client directory/Kafka/kafka/config/producer.properties

   In this example, the topic name is customer_source.

   sh kafka-console-producer.sh --broker-list IP address of the node where the Kafka Broker instance is deployed:Kafka port --topic customer_source --producer.config /opt/client/Kafka/kafka/config/producer.properties

   Enter the message content.

   3,zhangsan
   5,zhaosi
   1,xiaoming
   2,liuyang
   7,liubei
   10,guanyu
   20,zhaoyun

   Press Enter to send the message. The output in the kafka-console-consumer window in 4 is as follows:

   3,zhangsan,16,city c
   5,zhaosi,32,city e
   1,xiaoming,18,city a
   2,liuyang,14,city b
   7,liubei,41,city a