Application BLB instance

The flow chart for users employing an application BLB instance is as follows:

It is divided into the following four steps:

• Step I: Create an application BLB instance;
• Step II: Configure the server group, mainly including port configuration, health checks and server addition;
• Step III: Configure listener;
• Step IV: Monitor the system and configure alarms.

Create an application BLB instance

1. Log in to Baidu AI Cloud Platform, go to Product Services > Baidu Load Balancer (BLB) > Application Instance, and navigate to the Instance List page.
2. Click on Create Load Balancer to enter the Create Instance page.

Description:

Ensure the BCC instance is created before creating the BLB instance; otherwise, the BLB instance creation will fail.

3. Choose the configuration information.

• Basic Information: Select the region and set the instance name. Network: Choose the Virtual Private Cloud (VPC) to which the BLB and related BCC cloud resources will belong.

Notes Users need to specify a subnet when creating a BLB instance.

• Configure public network access: Select Enable or Disable Public network access based on actual conditions.

  Description:

  • If OFF is selected, the feature will not be enabled, meaning that no public IP will be bound to the BLB instance during its creation. You can bind a public IP later if required.
  • If ON is selected, the feature will be enabled, meaning that a public IP will be purchased and bound to the BLB instance during its creation.

• Purchase Information: Specify the purchase quantity and configure whether to enable auto-release.

Notes When creating a BLB instance, users can directly configure the Auto-release of BLB instance, and the BLB instance will be released automatically at the set time.

(Optional. If public network access is not enabled, the system will skip this step) Configure EIP instance information. For the configuration method of EIP instance, refer to [Create EIP Instance](EIP/Operation guide/EIP Instance/Create instance.md).

4. Verify the configuration details and complete the order and payment by following the system prompts. You will receive an SMS notification upon successful creation.

Configure server group

The steps for configuring a server group mainly include:

1. Fill in basic information of server group
2. Configure open ports;
3. Add server group;

Note: A single server group can support multiple open ports. For example, Server Group A can simultaneously open TCP 80 and HTTP 80 ports.

Fill in basic information of server group

Operation step

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. In the left navigation bar, select Target Group, click the Server Group tab on the details page, then choose Add Server Group to enter the configuration page and fill in the server group name and description.

Configure TCP protocol open ports

Operation step

1. Enter the Add Server Group configuration page, click Add Port to set the basic settings and health check of the listener, and open the protocol [Port] to select TCP.
2. Provide configuration details.

3. Set up health checks.

4. Once all configurations are complete, click the OK button to finalize the setup of the TCP protocol open port.

Configure UDP protocol open ports

Operation step

1. Enter the Add Server Group configuration page, click Add Port to set the basic settings and health check of the listener, and open the protocol [Port] to select UDP.
2. Provide configuration details.

3. Set up health checks.

4. Once all configurations are complete, click the OK button to finalize the setup of the UDP protocol open port.

Configure HTTP protocol open ports

1. Enter the Add Server Group configuration page, click Add Port to set the basic settings and health check of the listener, and open the protocol [Port] to select HTTP.
2. Provide configuration details.

3. Set up health check details.

4. After completing the configurations above, click OK to finalize the setup of the HTTP protocol server group.

Add server group

On the server group details page, click Add Server, select the server name you want to add to the group, click Next to set the server weight, and finally click OK to finish adding the server to the group.

Note:

• While adding servers, ensure that all servers belong to the same VPC as the application BLB instance.
• Set the weight for the real servers. The weight determines the distribution of request forwarding among the server instances. For instance, if two servers have different configurations, the more powerful server can be assigned a higher weight to handle more incoming requests.
• The weight value is relative. If all servers have the same weight, their request forwarding ratios will be equal.
• Supports setting a weight value ranging from 0 to 100. The higher the weight, the more requests the server will receive.
• Weights do not apply to forwarding rules other than weighted round robin. If the weight is set to "0", no new requests will be sent to the server.

Server security group settings

For the server security group settings of the application BLB instance, please refer to [Security Group Settings of General-purpose BCC Instance](BLB/Operation guide/General-purpose BLB instance/Creating BLB Ordinary Instance.md#Set security group for real servers).

Edit port

Under the Open Port tab, click Edit to access the editing interface. After making changes, click OK.

Delete port

1. In the Open Ports tab, select the listener settings you wish to delete, and click Delete.
2. In the pop-up confirmation window, click OK to finalize the release process.

Once you've filled in the server group's basic information, added servers, and configured open ports, click OK at the bottom of the page to complete the server group creation.

Configure IP group

The steps for configuring an IP group mainly include:

1. Fill in the basic information of IP group
2. Configure open protocol;
3. Add an IP address.

Notes

IP groups are currently only available to Allow List users. If required, submit a Ticket.

Fill in the basic information of IP group

Operation step

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. In the left navigation bar, select Target Group, go to the IP Group tab on the details page, click Add IP Group to access the configuration page, and complete the fields for the IP group name and description.

Configure TCP open protocol

Operation step

1. Go to the Add IP Group configuration page, click Add Protocol to configure the listener's basic settings and health check, and select TCP as the open protocol.
2. Provide configuration details.

3. Set up health checks.

4. After completing the settings above, click OK to finalize the setup of the TCP open protocol.

Configure UDP open protocol

Operation step

1. Go to the Add IP Group configuration page, click Add Protocol to configure the listener's basic settings and health check, and select UDP as the open protocol.
2. Provide configuration details.

3. Set up health checks.

4. After setting up the configurations, click OK to finalize the UDP open protocol configuration.

Configure HTTP open protocol

1. Go to the Add IP Group configuration page, click Add Protocol to configure the basic settings and health check for the listener, and choose HTTP as the open protocol.
2. Provide configuration details.

3. Set up health check details.

4. After configuring the settings, click OK to finalize the HTTP open protocol configuration.

Add IP group

In the server group details section, click Add IP, then open the Add IP menu, input the IP address and port to be added to the IP group, configure the weight, and finally click OK to complete the IP addition.

Description:

• While adding an IP, it can belong to the same VPC as the application BLB instance. If intranet connectivity is possible, it may also be from a cross-region VPC or a user IDC.
• Set the weight for each backend member (i.e., IP + port). Weight determines how requests are distributed across backend members. For instance, if two backend members have different configurations, the higher-configured member can be assigned a greater weight to handle more external requests.
• The weight value is relative. If all servers have the same weight, their request forwarding ratios will be equal.
• Supports setting a weight value ranging from 0 to 100. The higher the weight, the more requests the server will receive.
• Weights do not apply to forwarding rules other than weighted round robin. If the weight is set to "0", no new requests will be sent to the server.

Configure the listener for an application BLB Instance

It mainly includes the configuration of TCP, UDP, SSL, HTTP and HTTPS listener

TCP listener

Scenario overview

Key application scenarios for the TCP protocol include cases where reliability is critical, high data accuracy is required, and slower transmission speeds are acceptable.

Operation step

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. Click Listener Settings > Add Listener Settings in the left navigation bar to configure basic listener settings. Select TCP for listener protocol [Port].
4. Configure the necessary settings.

5. Advanced options

6. Define forwarding rules.

1> **Note:**
2>  TCP listeners has only one default forwarding rule, which cannot be deleted.
3>  For example: Forward the traffic received by this listener to TCP Port 80 of Server Group A. In the target server group, select Server Group A, and in the target port, select TCP 80.

7. After completing the above setup, click the OK button to finalize adding the TCP listener.

UDP listener

Scenario overview

Typical application scenarios for UDP protocol include DNS services, IoT applications, and situations where high reliability of data transmission is not required.

Operation step

When health checks are enabled, BLB automatically blocks backend members marked as unhealthy.

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. Click Listener Settings > Add Listener Settings in the left navigation bar to configure basic listener settings. Select UDP for listener protocol [port].
4. Configure the necessary settings.

5. Advanced options

6. Define forwarding rules.

1> **Note:**
2>  UDP listeners has only one default forwarding rule, which cannot be deleted.
3>  For example: Forward the traffic received by this listener to UDP Port 53 of Server Group A. In the target server group, select Server Group A, and in the target port, select UDP 53.

7. After completing the above setup, click the OK button to finalize adding the UDP listener.

SSL listener

Scenario overview

Common use cases for SSL protocols include environments requiring ultra-high performance and large-scale TLS offload.

Operation step

When health checks are enabled, BLB automatically blocks backend members marked as unhealthy.

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. Click Listener Settings > Add Listener Settings in the left navigation bar to configure basic listener settings. Select SSL for listener protocol [port].
4. Configure the necessary settings.

5. Advanced options

6. Define forwarding rules.

1> **Note:**
2>  SSL listeners has only one default forwarding rule, which cannot be deleted.

7. Once the above configurations are completed, click the OK button to add the SSL listener.

HTTP listener

Scenario overview

Typical usage scenarios for HTTP protocol include applications requiring the ability to recognize data content.

Operation step

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. Click Listener Settings > Add Listener Settings in the left navigation bar to configure basic listener settings. Select HTTP for listener protocol [port].
4. Configure the necessary settings.

5. Advanced options

6. Define forwarding rules.

Note:

• When domain name and URL conditions appear in a single rule at the same time, the conditions must be met at the same time before the match is successful.

• Domain name forwarding rule matching content restrictions:

  • Limit length <100
  • Wildcard only supports *
  • Wildcard * may appear 0 or 1 time
  • Wildcard * can match 0-n characters
  • Only prefix matching is supported, that is, \ * can only appear at the beginning of the domain name, for example: *.baidu.com

• URL forwarding rule matching content restrictions:

  • Limit length <100
  • Wildcard only supports *
  • Wildcard * may appear 0 or 1 time
  • Wildcard * can match 0-n characters
  • prefix, middle and suffix matchings are supported, that is, \ * can appear anywhere in the matching rule.

For instance: Route the traffic received by the listener to HTTP Port 80 of Server Group A. In the target server group setting, select Server Group A, and for the target port, choose HTTP 80.

7. Once the above configurations are completed, click the OK button to add the HTTP listener.

HTTPS listener

To enhance information security, users can configure the BLB listener protocol as HTTPS. BLB decrypts users' HTTPS requests and forwards them to backend members. Once backend members process the requests, response packets are sent back to BLB, encrypted, and delivered to the user. The process is illustrated in the diagram below:

Predecessor task

Before configuring an HTTPS listener, apply for a server certificate and upload it to the certificate management module. For details, refer to [Certificate Management](Reference/Certificate management/Introduction.md).

Operation step

1. Go to Product Services > Baidu Load Balancer (BLB) > Application Instance to access the application instance list.
2. Click on the link in the Load Balancer ID/Name column to proceed to the Instance Details page.
3. Click Listener Settings > Add Listener Settings in the left navigation bar to configure basic listener settings. Select HTTPS for listener protocol [Port].
4. Configure the necessary settings.

5. Advanced options

6. Define forwarding rules.

Note:

• When domain name and URL conditions appear in a single rule at the same time, the conditions must be met at the same time before the match is successful.

• Domain name forwarding rule matching content restrictions:

  • Limit length <100
  • Wildcard only supports *
  • Wildcard * may appear 0 or 1 time
  • Wildcard * can match 0-n characters
  • Only prefix matching is supported, that is, \ * can only appear at the beginning of the domain name, for example: *.baidu.com

• URL forwarding rule matching content restrictions:

  • Limit length <100
  • Wildcard only supports *
  • Wildcard * may appear 0 or 1 time
  • Wildcard * can match 0-n characters
  • prefix, middle and suffix matchings are supported, that is, \ * can appear anywhere in the matching rule.

For instance: Route the traffic received by the listener to HTTP Port 80 of Server Group A. In the target server group setting, select Server Group A, and for the target port, choose HTTP 80.

7. After configuring the parameters, click OK to complete the addition of the HTTPS listener.

Edit listener

Go to the Listener Settings tab, click Edit to enter the editing mode, make your changes, and then click OK to save.

Release listener

1. On the Listener Settings tab, choose the listener settings you want to release and click the Release button.
2. In the pop-up confirmation window, click OK to finalize the release process.