Use Application Load Balancers as targets of a Network Load Balancer - Elastic Load Balancing
Step 1: Create the Application Load BalancerStep 2: Create the target group Step 3: Create the Network Load BalancerStep 4: (Optional) Enable Amazon PrivateLink
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Use Application Load Balancers as targets of a Network Load Balancer

You can create a target group with a single Application Load Balancer as the target, and configure your Network Load Balancer to forward traffic to it. In this scenario, the Application Load Balancer takes over the load balancing decision as soon as traffic reaches it. This configuration combines the features of both load balancers and offers the following advantages:

  • You can use the layer 7 request-based routing feature of the Application Load Balancer in combination with features that the Network Load Balancer supports, such as endpoint services (Amazon PrivateLink) and static IP addresses.

  • You can use this configuration for applications that need a single endpoint for multi-protocols, such as media services using HTTP for signaling and RTP to stream content.

You can use this feature with an internal or internet-facing Application Load Balancer as the target of an internal or internet-facing Network Load Balancer.

Considerations

  • To associate an Application Load Balancer as a target of a Network Load Balancer, they must be in the same VPC within the same account.

  • You can associate an Application Load Balancer as a target of multiple Network Load Balancers. To do this, register the Application Load Balancer with a separate target group for each individual Network Load Balancer.

  • Each Application Load Balancer that you register with a Network Load Balancer decreases the maximum number of targets per Availability Zone per Network Load Balancer by 50. You can disable cross-zone load balancing in both load balancers to minimize latency and avoid Regional data transfer charges. For more information, see Quotas for your Network Load Balancers.

  • When the target group type is alb, you can't modify the target group attributes. These attributes always use their default values.

  • After you register an Application Load Balancer as a target, you can't delete the Application Load Balancer until you deregister it from all target groups.

  • The communication between a Network Load Balancer and an Application Load Balancer always uses IPv4.

Step 1: Create the Application Load Balancer

Before you begin, configure the target groups that this Application Load Balancer will use. Ensure that you have a virtual private cloud (VPC) with the targets that you will register with the target group. This VPC must have at least one public subnet in each of the Availability Zones used by your targets.

To create an Application Load Balancer using the console

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

  2. On the navigation pane, under Load Balancing, choose Load Balancers.

  3. Choose Create load balancer.

  4. Under Application Load Balancer, choose Create.

  5. On the Create Application Load Balancer page, under Basic configuration, specify the Load balancer name, Scheme, and IP address type.

  6. For Listeners, you can create an HTTP or HTTPS listener on any port. However, you must ensure that the port number of this listener matches the port of the target group in which this Application Load Balancer will reside.

  7. Under Availability Zones, do the following:

    1. For VPC, select a virtual private cloud (VPC) with instances or IP addresses that you included as targets of your Application Load Balancer. You must use the same VPC that you would use for your Network Load Balancer in Step 3: Create a Network Load Balancer, and configure the Application Load Balancer as its target.

    2. Select two or more Availability Zones and corresponding subnets. Ensure that these Availability Zones match those enabled for your Network Load Balancer to optimize availability, scaling, and performance.

  8. You can Assign a security group to your load balancer by creating a new security group or by selecting an existing one.

    The security group that you select should contain a rule that allows traffic to the listener port for this load balancer. Use the CIDR blocks (IP address range) of the client's computers as the traffic source in the inbound rules for security groups. This allows clients to send traffic through this Application Load Balancer. For more information about configuring security groups for an Application Load Balancer as a target of a Network Load Balancer, see Security groups for your Application Load Balancer in the User Guide for Application Load Balancers.

  9. For Configure Routing, select the target group that you configured for this Application Load Balancer. If you don't have an available target group, and want to configure a new one, see Create a target group in the User Guide for Application Load Balancers.

  10. Review your configuration, and choose Create load balancer.

Step 2: Create the target group with the Application Load Balancer as the target

Creating a target group allows you to register a new or existing Application Load Balancer as a target. You can only add one Application Load Balancer per target group. The same Application Load Balancer can also be used in a separate target group, as the target of up to two Network Load Balancers.

To create a target group and register the Application Load Balancer as a target, using the console

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

  2. On the navigation pane, under Load Balancing, choose Target Groups.

  3. Choose Create target group.

  4. On the Specify group details page, under Basic configuration, choose Application Load Balancer.

  5. For Target group name, enter a name for the Application Load Balancer target group.

  6. For Protocol, only TCP is allowed. Select the Port for your target group. This target group port must match the listener port of the Application Load Balancer. Alternatively, you can add or edit the listener port on the Application Load Balancer to match this port.

  7. For VPC, select the virtual private cloud (VPC) with the Application Load Balancer to register with the target group.

  8. For Health checks, choose HTTP or HTTPS as the Health check protocol. Health checks are sent to the Application Load Balancer and forwarded to its targets using the specified port, protocol, and ping path. Ensure that your Application Load Balancer can receive these health checks by having a listener with a port and protocol that matches the health check port and protocol.

  9. (Optional) Add one or more tags as required.

  10. Choose Next.

  11. On the Register targets page, choose the Application Load Balancer that you want to register as the target. The Application Load Balancer you choose from the list must have a listener on the same port as the target group you’re creating. You can add or edit a listener on this load balancer to match the target group’s port or return to the previous step and change the port that's specified for the target group. If you're unsure about which Application Load Balancer to add as the target, or don't want to add it at this point, you can choose to add the Application Load Balancer later.

  12. Choose Create target group.

Step 3: Create a Network Load Balancer, and configure the Application Load Balancer as its target

Use the following steps to create the Network Load Balancer and then configure the Application Load Balancer as its target using the console.

To create your Network Load Balancer and listener using the console

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

  2. On the navigation pane, under Load Balancing, choose Load Balancers.

  3. Choose Create load balancer.

  4. Under Network Load Balancer, choose Create.

  5. Basic configuration

    On the Basic configuration pane, configure Load balancer name, Scheme, and IP address type.

  6. Network mapping

    1. For VPC, select the same VPC that you used for your Application Load Balancer target. If you selected Internet-facing for Scheme, only VPCs with an internet gateway are available for selection.

    2. For Mappings, select one or more Availability Zones and corresponding subnets. We recommend that you select the same Availability Zones that are enabled for your Application Load Balancer. This optimizes availability, scaling, and performance.

      (Optional) To use static IP addresses, choose Use an Elastic IP address in the IPv4 settings for each Availability Zone. With static IP addresses you can add certain IP addresses to an allow list for firewalls, or you can hard code IP addresses with clients.

  7. Listeners and routing

    1. The default is a listener that accepts TCP traffic on port 80. Only TCP listeners can forward traffic to an Application Load Balancer target group. You must keep Protocol as TCP, but you can modify Port as needed.

      With this configuration, you can use HTTPS listeners on the Application Load Balancer to terminate TLS traffic.

    2. For Default action, select the Application Load Balancer target group to forward traffic. If you don't see it in the list, or can't select a target group (because it is already in use by another Network Load Balancer), you can create an Application Load Balancer target group as shown in Step 2: Create the target group with the Application Load Balancer as the target.

  8. Tags

    (Optional) Add tags to categorize your load balancer. For more information, see Tags.

  9. Summary

    Review your configuration, and choose Create load balancer.

To use the Network Load Balancer that you set up in the previous step as an endpoint for private connectivity, you can enable Amazon PrivateLink. This establishes a private connection to your load balancer as an endpoint service.

To create a VPC endpoint service using your Network Load Balancer

  1. On the navigation pane, choose Load Balancers.

  2. Select the name of the Network Load Balancer to open its details page.

  3. On the Integrations tab, expand VPC Endpoint Services (Amazon PrivateLink).

  4. Choose Create endpoint services to open the Endpoint services page. For the remaining steps, see Create an endpoint service in the Amazon PrivateLink Guide.