Before you use Message Queue for Apache Kafka to send and subscribe to messages, you must create resources in the Message Queue for Apache Kafka console. Otherwise, you cannot pass authentication or use the management and maintenance features. Resources here are topics and consumer groups.

Prerequisites

A Message Queue for Apache Kafka instance is purchased and deployed based on the network type.

Background information

After you deploy the Message Queue for Apache Kafka instance, you must create topics and consumer groups.
  • A topic is the first-level identifier for classifying messages in Message Queue for Apache Kafka . For example, you can create a topic named Topic_Trade for transaction-related messages. The first step to use Message Queue for Apache Kafka is to create a topic for your application.
  • A consumer group identifies a group of consumers that subscribe to and consume the same type of messages by using the same consumption logic. The relationship between consumer groups and topics is N:N. One consumer group can subscribe to multiple topics, and one topic can be subscribed to by multiple consumer groups.

Step 1: Create a topic

Perform the following steps to create a topic:

  1. Log on to the Message Queue for Apache Kafka console.
  2. In the Resource Distribution section of the Overview page, select the region where your instance resides.
    Notice You must create a topic in the region where your application resides. This means that you must select the region where your Elastic Compute Service (ECS) instance is deployed. A topic cannot be used across regions. For example, if a topic is created in the China (Beijing) region, the message producer and consumer must run on ECS instances in the China (Beijing) region.
  3. On the Instances page, click the name of the instance that you want to manage.
  4. In the left-side navigation pane, click Topics.
  5. On the Topics page, click Create Topic.
  6. In the Create Topic panel, set the properties of the topic and click OK.
    Create a topic
    Parameter Description Example
    Name The name of the topic. demo
    Description The description of the topic. demo test
    Partitions The number of partitions in the topic. 12
    Storage Engine The storage engine of the topic.

    Message Queue for Apache Kafka supports the following storage engines:

    • Cloud Storage: If this option is selected, disks provided by Alibaba Cloud are used and three replicas are stored in distributed mode. This type of storage engine features low latency, high performance, persistence, and high durability. If the disk type of your instance is Standard (High Write), you can select only Cloud Storage.
    • Local Storage: If this option is selected, the in-sync replicas (ISR) algorithm of open source Apache Kafka is used and three replicas are stored in distributed mode.
    Cloud Storage
    Message Type The message type of the topic.
    • Normal Message: By default, messages of the same key are stored in the same partition in the order in which they are sent. When a broker in the cluster fails, the messages may be out of order. If you set the Storage Engine parameter to Cloud Storage, this parameter is automatically set to Normal Message.
    • Partitionally Ordered Message: By default, messages of the same key are stored in the same partition in the order in which they are sent. When a broker in the cluster fails, the messages are stilled stored in the same partition in the order they are sent. However, specific messages in the partition cannot be sent until the partition is restored. If you set the Storage Engine parameter to Local Storage, this parameter is automatically set to Partitionally Ordered Message.
    Normal Message
    Log Cleanup Policy The log cleanup policy for the topic.

    If you set the Storage Engine parameter to Local Storage, you must set the Log Cleanup Policy parameter.

    Message Queue for Apache Kafka supports the following log cleanup policies:

    • Delete: The default log cleanup policy is used. If the remaining disk space is sufficient, messages are retained for the maximum retention period. If disk usage exceeds 85%, the disk space is insufficient, and earlier messages are deleted to ensure service availability.
    • Compact: The Apache Kafka log compaction policy is used. If the keys of different messages are the same, messages that have the latest key values are retained. This policy applies to scenarios in which the system is recovered from a system failure or the cache is reloaded after a system restart. For example, when you use Kafka Connect or Confluent Schema Registry, you must store the system status information or configuration information in a log-compacted topic.
      Notice Log-compacted topics are generally used only in specific ecosystem components, such as Kafka Connect or Confluent Schema Registry. Do not use this log cleanup policy for a topic that is used to send and subscribe to messages in other components. For more information, see Message Queue for Apache Kafka demos.
    Compact
    Tag The tags to be attached to the topic. demo
    After the topic is created, it is displayed on the Topics page.

Step 2: Create a consumer group

Perform the following steps to create a consumer group:

  1. Log on to the Message Queue for Apache Kafka console.
  2. In the Resource Distribution section of the Overview page, select the region where your instance resides.
  3. On the Instances page, click the name of the instance that you want to manage.
  4. In the left-side navigation pane, click Groups.
  5. On the Groups page, click Create Group.
  6. In the Create Group panel, enter the group name in the Group ID field and the group description in the Description field, attach tags to the consumer group, and then click OK.
    After the consumer group is created, it is displayed on the Groups page.

What to do next

Use an SDK to send and subscribe to messages based on the network type: