Server Load Balancer  Play Video

Server Load Balancer (SLB) distributes network traffic across groups of backend servers to improve the service capability and application availability. It provides functions as a reverse proxy at Layer 7(ALB)and load balancing services at Layer 4 (CLB).

Latest News

Release Notes

Application Load Balancer (ALB) is now available.

Learn More
Free Trial for Individuals

Receive a USD $15 Classic Load Balancer (CLB) credit

Learn More
Free Trial for Enterprise

Receive a USD $55 Classic Load Balancer (CLB) credit

Learn More

High Performance and Elasticity
Stable, Reliable, and Globally Available

Server Load Balancer (SLB) provides high-performance load balancing services. Classic Load Balancer (CLB) runs at Layer 4 and supports up to 100,000 QPS. The newly released Application Load Balancer (ALB) service is based on Alibaba Cloud Apsara Network 2.0 and supports up to 1,000,000 QPS.

The Server Load Balancer (SLB) instances feature high performance and support auto scaling. They can automatically adjust resources based on your business requirements to simplify O&M.

High Security and Reliability

Server Load Balancer (SLB) provides disaster recovery at four levels for high availability. CLB and ALB support built-in Anti-DDoS services to ensure business security. In addition, you can integrate ALB with WAF in the console to ensure security at the application layer.

Multiple Protocols

Server Load Balancer (SLB) supports multiple protocols, such as TCP and UDP at the network layer, and HTTP, HTTPS, QUIC, and gRPC at the application layer. ALB provides multiple advanced routing features at Layer 7.

Cloud-Native

ALB and CLB support cloud-native networks. ALB is integrated with other cloud-native services, such as Container Service for Kubernetes (ACK), Serverless App Engine (SAE), and Kubernetes, and functions as a cloud-native gateway to distribute inbound network traffic.

SLB Types

`
Type Application Load Balancer (ALB) Classic Load Balancer (CLB)
Service Scope Provides powerful processing capabilities at Layer 7 and multiple advanced routing features
Supports HTTP, HTTPS, and QUIC at Layer 7
Focuses on application delivery
Provides powerful processing capabilities for Layer 4 load balancing
Supports protocols such as TCP, UDP, HTTP, and HTTPS
Focuses on network delivery
Performance Based on the NFV platform
A single ALB instance supports 1,000,000 QPS
Developed on top of a physical machine architecture
Supports up to 5,000,000 connections
O&M Supports auto scaling to adjust processing capabilities based on inbound traffic Provides multiple specifications that you can specify based on the traffic peaks in your business
Cloud-Native Support Serves as a cloud native gateway to distribute and mirror network traffic and supports canary release and blue-green deployment Supports cloud-native services
Scenarios Provides high-performance services and supports auto scaling at Layer 7
Maintains low network latency for audio and video applications that handle a large amount of network traffic
Supports canary release and blue-green deployment for cloud native applications
Distributes network traffic across backend servers at Layer 4 to ensure the high availability of websites and systems
Supports a large number of concurrent connections to backend servers
Provides intra-region and cross-region disaster recovery
Pricing ALB Pricing Details > CLB Pricing Details >
Getting started Create an ALB Create a CLB

Features

Multiple Protocols

Supports multiple protocols to meet your business requirements in various scenarios.

Basic Protocols

Supports Layer 4 load balancing over TCP or UDP and Layer 7 loading balancing over HTTP or HTTPS

Advanced Protocols

Supports QUIC at the application layer. QUIC is an advanced protocol that improves transmission on audio, video, and mobile applications. ALB also supports gRPC, which facilitates efficient communication among microservices through API operations.

Multi-Level Disaster Recovery

Provides disaster recovery at multiple levels to ensure high availability.

Health Checks

Monitors the condition of backend servers regularly. SLB does not distribute network traffic to unhealthy backend servers to ensure availability.

Multi-Zone Deployment

Supports multi-zone deployment in specific regions to provide zone-disaster recovery.

Cluster Deployment and Session Synchronization

Server Load Balancer (SLB) supports cluster deployment and session synchronization. You can perform hot upgrades and monitor the health and performance of machines in real-time.

Secure and Reliable

Provides built-in security capabilities (free of charge) to secure transmission and reduce costs.

Layer 4 Security

Server Load Balancer (SLB) is resilient against DDoS, SYN flood, UDP flood, ACK flood, ICMP flood, and DNS flood attacks at Layer 4.

Layer 7 Security

Provides security capabilities at Layer 4 and Layer 7. Layer 7 supports the configuration read-only mode. You can integrate Server Load Balancer (SLB) with WAF to secure your applications.

Certificate Management

Provides certificate management for HTTPS requests to ensure the reliability and security of the transmission.

Flexible Scheduling

Supports multiple scheduling algorithms and forwarding methods to improve the application deployment flexibility.

Scheduling Algorithms

Supports Weighted Round Robin (WRR) and Weighted Least Connection (WLC). You can specify scheduling algorithms to distribute network traffic based on your business requirements.

Domain Name and URL Forwarding

Distributes network traffic across backend servers based on domain names and URLs. This improves the application deployment flexibility.

Flexible Management and Billing

Allows you to specify the instance type and billing method based on your business requirements. Alibaba Cloud also provides multiple methods to manage your Server Load Balancer (SLB) service.

Flexible Billing

Supports the pay-as-you-go and subscription billing methods and the pay-by-data-transfer and pay-by-bandwidth metering methods.

Flexible Management

You can create, configure, and manage Server Load Balancer (SLB) instances in the console by calling APIs in OpenAPI or using Alibaba Cloud SDKs.

Scenarios

Challenges

Workloads on backend servers are heavy during peak hours in the audio, video, and game industries:

• A large amount of network traffic is forwarded between clients and backend servers in scenarios, such as short videos, long videos, livestreaming, online education, and online games.

• Large traffic fluctuations occur in audio and video scenarios. This affects the performance, elasticity, stability, and availability of systems.

Benefits

  • High Performance

    Supports Cloud Network Management 2.0. A single SLB instance supports 1,000,000 QPS.

  • High Elasticity

    SLB automatically adjusts its processing capabilities based on the inbound traffic. You do not need to configure the service manually.

  • Advanced Protocol

    Supports QUIC to facilitate transmission for videos and reduce First Contentful Paint (FCP) time.

Alibaba Cloud CDN

A highly scalable and cost-effective service to accelerate content delivery.

Learn More

Anti-DDoS

Automatically protects your service from DDoS attacks.

Learn More

ApsaraDB for Redis

A fully-managed cloud database service that supports Redis.

Learn More

Requirements

Frequent business adjustment occurs in scenarios, such as new retail, new finance, product releases, and large-scale promotions.

Services must be secure, reliable, elastic, and ready to use after they are activated.

You must provide flexible billing to reduce costs.

Benefits

  • Ready-to-use

    You do not need to purchase or deploy any hardware. The SLB service is ready to use after it is activated. You can specify billing methods based on your business requirements. This allows you to manage your business flexibly and efficiently.

  • Scalability

    SLB automatically adjusts its processing capabilities based on inbound traffic. You do not need to configure the service manually in large-scale promotion scenarios.

  • High Security and Reliability

    Provides disaster recovery at four levels. SLB supports integration with Anti-DDoS and Cloud Firewall to secure your business.

Elastic Compute Service (ECS)

Provides elastic and secure servers to host your services on the cloud.

Learn More

Web Application Firewall (WAF)

Defends websites from common attacks at the application layer to ensure security and availability.

Learn More

Cloud Enterprise Network (CEN)

A global network that consists of interconnected hybrid clouds and distributed systems.

Learn More

Requirements

Enterprises from the Internet, finance, and enterprise sectors want to use advanced cloud-native technologies to deploy their new businesses on the cloud or adjust their current businesses.

You must use the cloud-native SLB service to use ACK, SAE, or Kubernetes.

Benefits

  • Cloud-Native

    Integrated with ACK, SAE, and Kubernetes. SLB functions as a cloud-native gateway on Alibaba Cloud to distribute inbound network traffic.

  • Fully Developed APIs

    SLB supports gRPC and provides fully-developed APIs that you can call to manage the connections to a large number of microservices.

Container Service for Kubernetes (ACK)

Provides secure and highly-available container services and supports stable upgrades.

Learn More

Elastic IP Address (EIP)

An independent public IP resource that allows flexible management.

Learn More

NAT Gateway

Functions as an Internet gateway for a VPC.

Learn More

Requirements

Multinational enterprises want to distribute network traffic from different regions across applications and connect their data centers to Alibaba Cloud in a cost-effective way.

They want to build a hybrid cloud or a cross-region network that provides multi-level disaster recovery.

Benefits

  • Support for All Regions

    Supports intelligent DNS resolution. Client traffic is directed to the best available IP addresses to accelerate transmission and improve the user experience.

  • Multi-Level Disaster Recovery

    SLB provides high availability across regions and zones.

  • Ease of Use

    You can use SLB and CEN to build a global network that connects data centers in different regions to Alibaba Cloud in a fast and simplified way.

Global Accelerator (GA)

Provides network acceleration services for your Internet-facing application globally.

Learn More

Cloud Enterprise Network (CEN)

Allows you to build a global network that consists of interconnected hybrid clouds and distributed systems with scalability and communication capabilities at the enterprise level.

Learn More

Object Storage Service (OSS)

Provides encrypted and secure storage services on the cloud.

Learn More

Product Updates

      More updates >

      Related Resources

      Global Network Solution
      Alibaba Cloud provides an end-to-end SDN solution for multinational enterprises. Users can easily communicate with each other through secure and reliable connections worldwide. The transmission efficiency is ensured.
      Global Acceleration Solution
      Accelerates your networks and applications, improves network performance, and secures applications. Alibaba Cloud has WAN infrastructure deployed on a global scale. You can control connections between enterprises through IT management. You can also accelerate applications within the global network.
      How Can a Server Load Balancer Help Your Website or Application?
      This blog introduces the concept of load balancing and discusses how Alibaba Cloud can help you speed up your websites or apps.
      Solving Server Reliability Problems with Server Load Balancer
      This blog provides information on how and which load balancing algorithms can solve server reliability issues during peak hours.
      Manage Traffic on Multiple Servers with Alibaba Cloud Server Load Balancer
      This tutorial describes how you can use Alibaba Cloud Server Load Balancer to distribute traffic across multiple servers.
      Use Server Load Balancer to Realize High Availability (Thai)
      Check out this webinar to learn how to respond to sudden traffic spikes and minimize response time with Server Load Balancer.
      Cloud Computing Essentials - Server Load Balancer
      In this program, the Alibaba Cloud expert introduces Alibaba Cloud essential products throughout the week. Each online class is 60-90 minutes followed by an online knowledge assessment to help you track and showcase your learning with exclusive e-certificates.
      Day 2 | Cloud Computing Essentials
      This is a two-part training series that introduces you to core Alibaba Cloud products. You must devote three hours each day to get familiar with the core products and understand the exam patterns.
      Connections Matter: Simplify Your Cloud Networking Infrastructure
      This whitepaper is the story of cloud networking and the array of products from Alibaba Cloud that enable an enterprise to manage and thrive in a world of networked virtual private clouds.

      Course: Handle Large Traffic with Load Balancer

      This course provides you basic information about the Server Load Balancer (SLB) service and the scenarios in which you can use the service. This course also provides you information about the features of SLB and how to use the service.

      0.01 USD

      List price: USD 10.00

      View Details

      Upgraded Support For You

      1 on 1 Presale Consultation, 24/7 Technical Support, Faster Response, and More Free Tickets.

      1 on 1 Presale Consultation

      Consulting by experienced cloud experts.Learn More

      24/7 Technical Support

      Extended service time from 10 hours 5 days a week to 24/7. Learn More

      6 Free Tickets per Quarter

      The number of free tickets doubled from 3 to 6 per quarter. Learn More

      Faster Response

      Shorten after-sale response time from 36 hours to 18 hours. Learn More