Buying a Kafka Instance

Kafka instances are tenant-exclusive, and physically isolated in deployment. You can customize the computing capabilities and storage space of a Kafka instance as required.

Preparing Instance Dependencies

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

**Table 1** Kafka resources
Resource	Requirement	Operations
VPC and subnet	You need to configure a VPC and subnet for the Kafka instance as required. You can use the current account's existing VPC and subnet or shared ones, or create new ones. VPC owners can share the subnets in a VPC with one or multiple accounts through Resource Access Manager (RAM). Through VPC sharing, you can easily configure, operate, and manage multiple accounts' resources at low costs. For more information about VPC and subnet sharing, see VPC Sharing. Note: VPCs must be created in the same region as the Kafka instance.	For details on how to create a VPC and a subnet, see Creating a VPC. If you need to create and use a new subnet in an existing VPC, see Creating a Subnet for the VPC.
Security group	Different Kafka instances can use the same or different security groups. Before accessing a Kafka instance, configure security groups based on the access mode. For details, see Table 2.	For details on how to create a security group, see Creating a Security Group. For details on how to add rules to a security group, see Adding a Security Group Rule.
EIP	To access a Kafka instance on a client over a public network, create EIPs in advance. Note the following when creating EIPs: The EIPs must be created in the same region as the Kafka instance. The number of EIPs must be the same as the number of Kafka instance brokers. The Kafka console cannot identify IPv6 EIPs.	For details about how to create an EIP, see Assigning an EIP.

Procedure

Go to the Buy Instance page.
Specify Billing Mode.
- Yearly/Monthly: To create an instance, determine how long you would like to use it and it will be billed at the current price immediately.
- Pay-per-use: To create an instance, there is no need to specify a subscription because the instance will be billed based on usage duration.
Select a region.

DMS for Kafka instances in different regions cannot communicate with each other over an intranet. Select a nearest location for low latency and fast access.
Select a Project.

Projects isolate compute, storage, and network resources across geographical regions. For each region, a preset project is available.
Select an AZ.

An AZ is a physical region where resources use independent power supply and networks. AZs are physically isolated but interconnected through an internal network.

Select one AZ or at least three AZs.
Enter an Instance Name.

You can customize a name that complies with the rules: 4–64 characters; starts with a letter; can contain only letters, digits, hyphens (-), and underscores (_).
Select an Enterprise Project.

This parameter is for enterprise users. An enterprise project manages cloud resources. The enterprise project management service unifies cloud resources in projects, and resources and members in a project. The default project is default.
Configure the following instance specifications:

Specifications: Select Cluster or Custom. Alternatively, select Single-node.
- Cluster: Specify the version, broker flavor and quantity, disk type, and disk size to be supported by the Kafka instance as required.
  1. Version: Version of Kafka. Options: 1.1.0 , 3.x, or 2.7. This setting is fixed once the instance is created.
  2. Broker Flavor: Select a broker flavor that best fit your needs.
    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.
  3. For Brokers, specify the broker quantity.
  4. Storage space per broker: Disk type and size for storing the instance data. The disk type cannot be changed once the Kafka 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.
    
    The disk supports high I/O, ultra-high I/O, Extreme SSD, and General Purpose SSD types. For more information, see Disk Types and Performance.
  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 Cluster instance specifications
- Custom: The system calculates Brokers and Storage Space per Broker, and provides Recommended Specifications based on your specified parameters: Peak Creation Traffic, Retrieval Traffic, Replicas per Topic, Total Partitions, and Messages Created During Retention Period. This function is not supported in v3.x.
  Figure 2 Specification calculation
- Single-node: A v2.7 instance with one broker will be created. For details about single-node instances, see Comparing Single-node and Cluster Kafka Instances. Single-node instances are available in certain regions.
  1. Version: Kafka version, which can only be 2.7.
  2. Broker Flavor: Select a broker flavor that best fit your needs.
  3. Brokers: The instance can have only one broker.
  4. Storage space per broker: Disk type and size for storing the instance data. The disk type cannot be changed once the Kafka 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.
    
    The disk supports high I/O, ultra-high I/O, Extreme SSD, and General Purpose SSD types. For more information, see Disk Types and Performance.
  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 3 Single-node instance specifications
Configure the instance network parameters.
- Select the created or shared VPC and subnet from the VPC drop-down list.
  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.
- For Private IP Addresses, select Auto or Manual.
  - Auto: The system automatically assigns an IP address from the subnet.
  - Manual: Select IP addresses from the drop-down list.
  In regions except for the following ones, Private IP Addresses has been moved to the Private Network Access area. For details, see 10.
  - CN North-Beijing1
  - ME-Riyadh
  - LA-Sao Paulo1
  - LA-Santiago
- 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.
  
  Before accessing a Kafka instance on the client, configure security group rules based on the access mode. For details about security group rules, see Table 2.

Configure the instance access mode.

**Table 2** Instance access modes
Public or Private Network	Plaintext or Ciphertext	Description
Private Network Access	Plaintext Access	Clients connect to the Kafka instance without SASL authentication. Once enabled, private network access cannot be disabled. Enable plaintext or ciphertext access, or both.
	Ciphertext Access	Clients connect to the Kafka instance with SASL authentication. Once enabled, private network access cannot be disabled. Enable plaintext or ciphertext access, or both. To disable ciphertext access, contact customer service. If you enable Ciphertext Access, specify a security protocol, SASL/PLAIN, username, and password. After an instance is created, disabling and re-enabling Ciphertext Access do not affect users.
	Private IP Addresses	Select Auto or Manual. Auto: The system automatically assigns an IP address from the subnet. Manual: Select IP addresses from the drop-down list. If the number of selected IP addresses is less than the number of brokers, the remaining IP addresses will be automatically assigned.
Public Network Access	Plaintext Access	Clients connect to the Kafka instance without SASL authentication. Enable or disable plaintext access, and configure addresses for public network access.
	Ciphertext Access	Clients connect to the Kafka instance with SASL authentication. Enable or disable ciphertext access, and configure addresses for public network access. If you enable Ciphertext Access, specify a security protocol, SASL/PLAIN, username, and password. After an instance is created, disabling and re-enabling Ciphertext Access do not affect users.
	Public IP Addresses	Select the number of public IP addresses as required. If EIPs are insufficient, click Create Elastic IP to create EIPs. Then, return to the Kafka console and click next to Public IP Address to refresh the public IP address list. Kafka instances only support IPv4 EIPs.

Ciphertext access is unavailable for single-node instances.

The security protocol, SASL/PLAIN mechanism, username, and password are described as follows.

**Table 3** Ciphertext access parameters
Parameter	Value	Description
Security Protocol	SASL_SSL	SASL is used for authentication. Data is encrypted with SSL certificates for high-security transmission. SCRAM-SHA-512 is enabled by default. To use PLAIN, enable SASL/PLAIN. 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.
Security Protocol	SASL_PLAINTEXT	SASL is used for authentication. Data is transmitted in plaintext for high performance. SCRAM-SHA-512 is enabled by default. To use PLAIN, enable SASL/PLAIN. SCRAM-SHA-512 authentication is recommended for plaintext transmission.
Cross-VPC Access Protocol	-	When Plaintext Access is enabled and Ciphertext Access is disabled, PLAINTEXT is used for Cross-VPC Access Protocol. When Ciphertext Access is enabled and Security Protocol is SASL_SSL, SASL_SSL is used for Cross-VPC Access Protocol. When Ciphertext Access is enabled and Security Protocol is SASL_PLAINTEXT, SASL_PLAINTEXT is used for Cross-VPC Access Protocol. Fixed once the instance is created.
SASL/PLAIN	-	If SASL/PLAIN is disabled, the SCRAM-SHA-512 mechanism is used for username and password authentication. 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 ciphertext access is enabled.
Username and Password	-	Username and password used by the client to connect to the Kafka instance. A username should contain 4 to 64 characters, start with a letter, and contain only letters, digits, hyphens (-), and underscores (_). A password must meet the following requirements: Contains 8 to 32 characters. Cannot start with a hyphen (-) and must contain at least three of the following character types: uppercase letters, lowercase letters, digits, spaces, and special characters `~! @#$ %^&*()-_=+\\|[{}];:'",<.>? Cannot be the username spelled forwards or backwards. The username cannot be changed once ciphertext access is enabled.

Instance access mode parameters are not available in the following regions.

CN North-Beijing1
ME-Riyadh
LA-Sao Paulo1
LA-Santiago

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.
- In regions except for the following ones, Kafka SASL_SSL has been moved to the Private Network Access and Public Network Access areas. For details, see 10.
  - CN North-Beijing1
  - ME-Riyadh
  - LA-Sao Paulo1
  - LA-Santiago
- Single-node instances do not have this parameter.
Specify the required duration.

This parameter is displayed only if the billing mode is yearly/monthly. If Auto-renew is selected, the instance will be renewed automatically.
- Monthly subscriptions auto-renew for 1 month every time.
- Yearly subscriptions auto-renew for 1 year every time.

Click Advanced Settings to configure more parameters.

Configure public access.
Public access is disabled by default. You can enable or disable it as required.

After public access is enabled, configure an IPv4 EIP for each broker.
Public Network Access is no longer under Advanced Settings in regions except for the following ones. For details, see 10.
- CN North-Beijing1
- ME-Riyadh
- LA-Sao Paulo1
- LA-Santiago
Configure Smart Connect.
Smart Connect is used for data synchronization between heterogeneous systems. You can configure Smart Connect tasks to synchronize data between Kafka and another cloud service or between two Kafka instances.

Enabling Smart Connect creates two brokers.

Single-node instances do not have this parameter.

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. The default topic parameters are listed in Table 4.

After you change the value of the log.retention.hours (retention period), default.replication.factor (replica quantity), or num.partitions (partition quantity) 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 parameters listed in Table 4.

**Table 4** Topic parameters
Parameter	Default Value	Modified Value
Partitions	3	5
Replicas	3	3
Aging Time (h)	72	72
Synchronous Replication	Disabled	Disabled
Synchronous Flushing	Disabled	Disabled
Message Timestamp	CreateTime	CreateTime
Max. Message Size (bytes)	10,485,760	10,485,760

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 your organization has configured tag policies for DMS for Kafka, add tags to Kafka instances based on the policies. If a tag does not comply with the policies, Kafka instance creation may fail. Contact your organization administrator to learn more about tag policies.
- 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.
Enter a Description of the instance for 0–1024 characters.

Click Buy.
Confirm the instance information, and read and agree to the HUAWEI CLOUD Customer Agreement. If you have selected the yearly/monthly billing mode, click Pay Now and make the payment as prompted. If you have selected the pay-per-use mode, click Submit.
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.