Managing Messages in Kafka Topics

Scenario

You can produce or consume messages in Kafka topics using the MRS cluster client.

Prerequisites

• The cluster client has been installed.
• For clusters with Kerberos authentication enabled, you need to create a service user on Manager in advance. The user has the permission to perform operations in Kafka topics.

Procedure

1. Go to the Kafka service page.
   • For versions earlier than MRS 3.x, click the cluster name to go to the cluster details page and choose Components > Kafka.
     

     If the Components tab is unavailable, complete IAM user synchronization first. (On the Dashboard page, click Synchronize on the right side of IAM User Sync to synchronize IAM users.)

   • For MRS 3.x or later, log in to FusionInsight Manager and choose Cluster > Name of the desired cluster > Services > Kafka.

2. Click instance. Query the IP addresses of the Kafka broker instances.

   Record the IP address of any Kafka instance.

3. Prepare the client based on service requirements. Log in to the node where the client is installed.

   Log in to the node where the client is installed. For details, see Using an MRS Client. .)

4. Run the following command to switch to the client installation directory, for example, /opt/client/Kafka/kafka/bin.

   cd /opt/client/Kafka/kafka/bin

5. Run the following command to configure environment variables:

   source /opt/client/bigdata_env

6. For clusters with Kerberos authentication enabled, run the following command to authenticate the user. For clusters with Kerberos authentication disabled, skip this step.

   kinit Kafka user

7. Manage messages in Kafka topics using the following commands:
   • Producing messages

     sh kafka-console-producer.sh --broker-list IP address of the node where the broker instance is located:9092 --topic Topic name --producer.config /opt/client/Kafka/kafka/config/producer.properties

     A topic must be created in advance. You can input specified information as the messages produced by the producer and then press Enter to send the messages. To end message producing, press Ctrl + C to exit.

   • Consuming messages

     Start another client connection and run the following commands to consume messages in the topic:

     cd /opt/client/Kafka/kafka/bin

     source /opt/client/bigdata_env

     sh kafka-console-consumer.sh --topic Topic name --bootstrap-server IP address of the node where the broker instance is located:9092 --consumer.config /opt/client/Kafka/kafka/config/consumer.properties

     In the configuration file, group.id (indicating the consumer group) is set to example-group1 by default. Users can change the value as required. The value takes effect each time consumption occurs.

     By default, the system reads unprocessed messages in the current consumer group when the command is executed. If a new consumer group is specified in the configuration file and the --from-beginning parameter is added to the command, the system reads all messages that have not been automatically deleted in Kafka.