Buying a Kafka Instance

Scenario

Your Kafka instance will be exclusive and deployed in physical isolation. You can customize the computing capabilities and storage space of an instance based on service requirements.

Prerequisites

Before creating a Kafka instance, prepare the resources listed in Table 1.

Buying a Kafka Instance

1. Log in to the console.
2. Click in the upper left corner to select a region.
   

   Select the region your application is in.

3. Click in the upper left corner and choose Application > Distributed Message Service for Kafka to open the console of DMS for Kafka.
4. Click Buy Instance in the upper right corner of the page.
5. Specify Billing Mode, Region, Project, and AZ.
6. Enter an instance name and select an enterprise project.
7. Configure the following instance parameters:
   1. Version: Kafka v1.1.0, v2.3.0, and v2.7 are supported. v2.7 is recommended. The version cannot be changed once the instance is created.
   2. CPU Architecture: Retain the default value.
   3. Broker Flavor: Select broker specifications that best fit your needs. For Brokers, specify the broker quantity.

      Maximum number of partitions per broker x Number of brokers = Maximum number of partitions of an instance. If the total number of partitions of all topics exceeds the upper limit of partitions, topic creation fails.

   4. Storage Space per Broker: Disk type and total disk space for storing the instance data. The disk type cannot be changed once the instance is created.

      The storage space is consumed by message replicas, logs, and metadata. Specify the storage space based on the expected service message size, the number of replicas, and the reserved disk space. Each Kafka broker reserves 33 GB disk space for storing logs and metadata.

      Disks are formatted when an instance is created. As a result, the actual available disk space is 93% to 95% of the total disk space.

   5. Capacity Threshold Policy: policy used when the disk usage reaches the threshold. The capacity threshold is 95%.
      • Automatically delete: Messages can be created and retrieved, but 10% of the earliest messages will be deleted to ensure sufficient disk space. This policy is suitable for scenarios where no service interruption can be tolerated. Data may be lost.
      • Stop production: New messages cannot be created, but existing messages can still be retrieved. This policy is suitable for scenarios where no data loss can be tolerated.
   Figure 1 Creating a Kafka instance
   

8. Configure the instance network parameters.
   • Select a VPC and a subnet.

     A VPC provides an isolated virtual network for your Kafka instances. You can configure and manage the network as required.

     

     After the Kafka instance is created, its VPC and subnet cannot be changed.

   • Select a security group.

     A security group is a set of rules for accessing a Kafka instance. You can click Manage Security Group to view or create security groups on the network console.

9. Configure Kafka SASL_SSL.

   This parameter indicates whether to enable SASL authentication when a client connects to the instance. If you enable Kafka SASL_SSL, data will be encrypted for transmission to enhance security.

   This setting is enabled by default. It cannot be changed after the instance is created. If you want to use a different setting, you must create a new instance.

   After Kafka SASL_SSL is enabled, you can determine whether to enable SASL/PLAIN. If SASL/PLAIN is disabled, the SCRAM-SHA-512 mechanism is used to transmit data. If SASL/PLAIN is enabled, both the SCRAM-SHA-512 and PLAIN mechanisms are supported. You can select either of them as required. The SASL/PLAIN setting cannot be changed once the instance is created.

   What are SCRAM-SHA-512 and PLAIN mechanisms?

   • SCRAM-SHA-512: uses the hash algorithm to generate credentials for usernames and passwords to verify identities. SCRAM-SHA-512 is more secure than PLAIN.
   • PLAIN: a simple username and password verification mechanism.

   If you enable Kafka SASL_SSL, you must also set the username and password for accessing the instance.

10. Configure the username and password for logging in to Kafka Manager. The Kafka Manager username cannot be changed once the instance is created.

    Kafka Manager is an open-source tool for managing Kafka clusters. After a Kafka instance is created, you can go to the instance details page to obtain the address for logging in to Kafka Manager. In Kafka Manager, you can view the monitoring statistics and broker information of your Kafka clusters.

11. Click Advanced Settings to configure more parameters.
    1. Configure Automatic Topic Creation.

       This setting is disabled by default. You can enable or disable it as required.

       If this option is enabled, a topic will be automatically created when a message is produced in or consumed from a topic that does not exist. By default, the topic has the following parameters:

       • Partitions: 3
       • Replicas: 3
       • Aging Time: 72
       • Synchronous Replication and Synchronous Flushing disabled
       • Message Timestamp: CreateTime
       • Max.Message Size (bytes): 10,485,760

       After you change the value of the log.retention.hours, default.replication.factor, or num.partitions parameter, the value will be used in later topics that are automatically created.

       For example, assume that num.partitions is changed to 5, an automatically created topic has the following parameters:

       • Partitions: 5
       • Replicas: 3
       • Aging Time: 72
       • Synchronous Replication and Synchronous Flushing disabled
       • Message Timestamp: CreateTime
       • Max.Message Size (bytes): 10,485,760
    2. Specify Tags.

       Tags are used to identify cloud resources. When you have multiple cloud resources of the same type, you can use tags to classify them based on usage, owner, or environment.

       • If you have predefined tags, select a predefined pair of tag key and value. You can click View predefined tags to go to the Tag Management Service (TMS) console and view or create tags.
       • You can also create new tags by specifying Tag key and Tag value.

       Up to 20 tags can be added to each Kafka instance. For details about the requirements on tags, see Configuring Kafka Instance Tags.

    3. Enter a description of the instance.

12. Click Buy.
13. Confirm the instance information, and click Submit.
14. Return to the instance list and check whether the Kafka instance has been created.

    It takes 3 to 15 minutes to create an instance. During this period, the instance status is Creating.

    • If the instance is created successfully, its status changes to Running.
    • If the instance is in the Creation failed state, delete it by referring to Deleting Kafka Instances. Then create a new one. If the instance creation fails again, contact customer service.
      

      Instances that fail to be created do not occupy other resources.