Application Load Balancer (ALB) is an Alibaba Cloud service that runs at the application layer and is optimized to balance traffic over HTTP, HTTPS, and Quick UDP Internet Connections (QUIC). ALB is highly elastic and can scale on demand to process large volumes of Layer 7 traffic. ALB also provides an availability SLA of up to 99.995%. ALB supports complex routing. ALB is integrated with other cloud-native services and is designed to serve as an ingress gateway to manage inbound traffic on Alibaba Cloud.

ALB architecture

Why ALB?

As a cloud-native ingress gateway on Alibaba Cloud, Application Load Balancer (ALB) is intended for Layer 7 load balancing over HTTP, HTTPS, and QUIC and provides advanced routing features. For more information about ALB Ingresses, see ALB Ingress overview and Functions and features of ALB Ingresses.

Application layer elasticity

ALB is intended for Layer 7 load balancing and provides domain names and virtual IP addresses to handle large amounts of network traffic at multiple levels. ALB distributes network traffic across groups of backend servers and automatically scales in response to the volume of inbound traffic. This not only improves the availability of your applications, but also helps prevent service interruptions caused by single points of failure (SPOFs). ALB supports cross-zone deployment and elastic scaling across zones to prevent resource insufficiency in individual zones.

Advanced protocols

ALB supports HTTP, HTTPS, and QUIC and can process a heavy load of network traffic. You can use ALB to provide fast and secure connections to mobile Internet applications such as real-time audio and video applications, interactive streaming applications, and online game applications. ALB supports Google Remote Procedure Call (gRPC), a high-performance remote procedure call framework that can efficiently interconnect microservices through APIs.

Content-based routing

ALB can route network traffic to different backend servers based on the request content such as the path, HTTP header, query string, HTTP request method, cookie, and source IP address. ALB also supports advanced configurations such as redirects, rewrites, and custom HTTPS headers.

Security and reliability

ALB supports DDoS mitigation and can be integrated with Web Application Firewall (WAF) to provide more security features. In addition, ALB supports end-to-end HTTPS encryption and allows you to customize security policies and cryptographic protocols such as TLS 1.3 as needed to protect your business-critical services and comply with the Zero Trust security framework.


As more and more cloud-native services are developed, a growing number of customers in the Internet, finance, and enterprise sectors choose to deploy their applications in the cloud or migrate their existing business systems to the cloud. As a cloud-native ingress gateway for Alibaba Cloud, ALB is deeply integrated with Container Service for Kubernetes (ACK), Serverless App Engine (SAE), Function Compute, and Kubernetes.

Flexible billing

ALB uses elastic IP addresses (EIPs) and EIP bandwidth plans to provide Internet-facing services and supports flexible billing for Internet data transfer. ALB also supports the pay-by-LCU metering method, which allows you to pay only for the resources that you use.

Performance metrics

ALB supports the Dynamic IP and Static IP modes. The performance of an ALB instance varies based on the IP mode.

Note The performance metrics vary only based on the IP mode of the ALB instance, and are not affected by the ALB instance edition.
Table 1. Performance of an ALB instance deployed across two zones in dynamic IP mode
IP modeMaximum number of queries per second (QPS)Maximum number of connections per second (CPS)Maximum number of concurrent connectionsMaximum private bandwidthMaximum Internet bandwidth
Dynamic IP1,000,0001,000,00010,000,000100 Gbps400 Mbps

If you require a larger bandwidth capacity, purchase an EIP bandwidth plan. For more information, see Create an EIP bandwidth plan.

Table 2. Performance of an ALB instance deployed across two zones in static IP mode
IP modeMaximum QPSMaximum CPSMaximum number of concurrent connectionsMaximum private bandwidthMaximum Internet bandwidth
Static IP100,000100,0001,000,00010 Gbps400 Mbps

If you require a larger bandwidth capacity, purchase an EIP bandwidth plan. For more information, see Create an EIP bandwidth plan.

  • In static IP mode, you can use CNAME records or A records to provide services, and an ALB instance deployed across two zones supports up to 100,000 QPS. In dynamic IP mode, you can use CNAME records to provide services, and an ALB instance deployed across two zones supports up to 1,000,000 QPS.
  • ALB supports multi-zone deployment. If the current region has two or more zones, you must select at least two zones to ensure high availability. If you select multiple zones for an ALB instance, you are not charged additional fees.

ALB components

ALB components
InstanceALB provides ultra-high Layer 7 processing capabilities and can increase the service capacity of your applications by distributing network traffic across different backend servers. Each ALB instance supports up to one million QPS.
ListenerA listener is the smallest configurable unit of ALB. Listeners check for requests over the protocols and ports that you configure. For example, you can configure a listener of ALB to process HTTP requests on port 80. You must add at least one listener to each ALB instance before the ALB instance can distribute network traffic. You can add at most 50 listeners to each ALB instance to distribute network traffic for different workloads.
Forwarding ruleALB distributes requests to one or more backend servers in server groups based on forwarding rules. ALB provides advanced routing features. In addition to the basic routing features, you can specify conditions such as the HTTP header, cookie, and HTTP method in a forwarding rule to route network traffic to different backend servers.
Server groupBackend servers can be organized into logical groups (also known as server groups) to which requests are distributed. Each server group contains one or more backend servers that process requests distributed by ALB. Server groups of ALB are independent of ALB. You can associate a server group with different ALB instances. You can specify up to 1,000 backend servers in each server group. ALB supports multiple types of backend servers. For example, you can specify Elastic Compute Service (ECS) instances, elastic container instances, and elastic network interfaces (ENIs) as backend servers.
Health checkALB checks the availability of backend servers by performing health checks. If a backend server is declared unhealthy, ALB does not forward requests to the backend server. ALB supports flexible health check configurations. For example, you can specify the protocol, port, and thresholds for health checks. ALB provides health check templates that can be applied to different server groups.

ALB types

Alibaba Cloud provides Internet-facing and internal-facing ALB instances. You can specify the type of ALB instance based on your business requirements. Whether EIPs and EIP bandwidth plans are used is based on the specified type of ALB instance.

EIP bandwidth planEIP bandwidth plans allow you to share and transfer bandwidth resources within the same region. EIP bandwidth plans support multiple metering methods such as pay-by-bandwidth and pay-by-enhanced-95th-percentile. You can use EIP bandwidth plans to reduce your Internet bandwidth costs. Internet-facing ALB instances use EIPs and EIP bandwidth plans that support the pay-by-bandwidth and pay-by-enhanced-95th-percentile metering methods to provide Internet-facing services.
Domain nameA domain name that can be accessed over the Internet or private networks and can be resolved to the virtual IP address of an ALB instance. You can also create a CNAME record to map a readable domain name to the domain name of ALB. For more information, see Configure a CNAME record.
EIPEIPs are required only by Internet-facing ALB instances. You do not need to associate EIPs with internal-facing ALB instances. An EIP is an IP address that ALB uses to provide services over the Internet. You can associate multiple EIPs with an Internet-facing ALB instance. To ensure high availability, Internet-facing ALB must use at least two EIPs in different zones to provide services.
Virtual IP addressVirtual IP addresses of ALB are used to receive and forward requests. Each virtual IP address is a private IP address that belongs to a virtual private cloud (VPC).

Activate ALB

Click the following button to go to the ALB buy page.

Create ALB instances

Deploy and maintain ALB instances

After you create an Alibaba Cloud account, you can deploy and manage ALB instances in the following ways:

  • ALB console: a web interface that you can use to manage your ALB service. You can create, use, or release ALB instances in the console. For more information, see Create an ALB instance.
  • Alibaba Cloud SDKs: SDKs for Java, Go, Python, and other programming languages.
  • OpenAPI Explorer: allows you to retrieve and call API operations, and dynamically generate SDK sample code.
  • Terraform: uses configuration files to call computing resources of Alibaba Cloud and other platforms that support Terraform. Terraform is an open source tool that implements version control.