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Load Balancer

Document

Announcement

ALB instance upgrade announcement

Network Load Balancer Commercially Available

Classic Load Balancer (CLB) Monitoring Metrics Upgrade Notice

What's New

Network Load Balancer (NLB)

What's New

Product Description

What is Network Load Balancer

Features

Benefits

Application scenarios

Limitations

Regions and Availability Zones

Billing

Quick Start

Setting up an IPv4 Network Load Balancer

Setting up an IPv6 Network Load Balancer

User Guide

NLB instances

NLB Instance Overview

Creating an NLB instance

Configuring the security group and Network ACL for NLB

Changing the NLB instance availability zone

Changing the NLB instance network type

Changing NLB instance IP version

Enabling/Disabling modification protection

Enabling/Disabling all zones forwarding

Adding to/Removing from a bandwidth package

Managing the associated security group

Deleting NLB instance

Server Group

Server group overview

Creating a server group

Adding or removing a backend server

Configuring backend server security group and Network ACL

Configuring a secondary network interface routing

Modifying a server group

Allowing backend security group

Deleting a server group

Listeners

Listener overview

Adding a listener

Starting/Stopping a listener

Modifying a listener

Deleting a listener

TLS Security Policy and Certificate

TLS Overview

Creating/Deleting a security policy

Adding/Removing an additional certificate

Replacing the certificate

Health Check

Health check overview

Editing health check

Viewing the health status

Access Log

Access log overview

Managing an access log

Projects and Tags

Project management

Tag Management

Viewing monitoring data

IAM

IAM overview

NLB IAM policy types

NLB custom policy examples

Best Practices

Troubleshooting exceptions found in health check

Full port listening example

Obtaining the client Source IP address

Migrating from CLB to NLB

Cross-VPC Backend Server

Cross-VPC ECS instances as backend servers (CEN)

ECS instances across VPCs serve as backend servers (Transit Router)

Cross-VPC ECS instance as a backend server (VPN connection)

On-premises IDC servers as backend servers

TLS listener mutual authentication

NLB providing certificate authentication for MQTT services

Viewing an NLB flow log

API

Call Methods

NLB Instance

CreateNetworkLoadBalancer - Creating a NLB instance

DeleteNetworkLoadBalancer - Deleting a NLB instance

ModifyNetworkLoadBalancerAttributes - Modifying an NLB instance

ModifyNetworkLoadBalancerZones - Adding or deleting a availability zone for an NLB instance

ModifyNetworkLoadBalancerSecurityGroups - Modifying security groups associated with an NLB instance

ModifyNetworkLoadBalancerNetworkType - Modifying the network type of an NLB instance

ModifyNetworkLoadBalancerBandwidthPackage - Adding or removing a public NLB instance to or from a Bandwidth Package

DescribeNetworkLoadBalancers - Querying a qualified NLB instance

DescribeNetworkLoadBalancerAttributes - Viewing the details of a NLB instance

DescribeNLBZones - Querying the availability zone information in the current region

ModifyNetworkLoadBalancerAccessLog - Configuring an access log

Listener

CreateNLBListener - Adding a listener

DeleteNLBListener - Deleting a listener

ModifyNLBListenerAttributes - Modifying a listener

DescribeNLBListeners - Querying qualified listeners

DescribeNLBListenerAttributes - Viewing the listener details

DescribeNLBListenerHealth - Viewing the backend server health status

DescribeNLBListenerCertificates - Querying the certificate information for a specified TLS listener

ModifyNLBListenerAdditionalCertificates - Attaching or detaching an additional certificate for TLS listeners

Server group

CreateNLBServerGroup - Creating a server group

DeleteNLBServerGroup - Deleting a server group

ModifyNLBServerGroupAttributes - Modifying a server group

DescribeNLBServerGroups - Querying the qualified server groups

DescribeNLBServerGroupAttributes - Viewing the server group details

AddNLBBackendServers - Adding a backend server

RemoveNLBBackendServers - Removing a backend server

ModifyNLBBackendServersAttributes - Modifying the backend server information

TLS Security Policy

CreateNLBSecurityPolicy - Creating a TLS custom security policy

ModifyNLBSecurityPolicyAttributes - Modifying the TLS custom security policy

DeleteNLBSecurityPolicy - Deleting a TLS custom security policy

DescribeNLBSecurityPolicies - Querying the qualified TLS custom security policy

DescribeNLBSystemSecurityPolicies - Querying the TLS system security policy

Tags

TagNLBResources - Adding a custom tag to NLB resources

UntagNLBResources - Deleting a custom tag from NLB resources

ListTagsForNLBResources - Querying the qualified tag information

SDK Reference

NLB SDK Overview

Viewing an SDK sample code

FAQ

NLB instance

NLB resource pack

Application Load Balancer (ALB)

Updates and Announcements

New feature release notes

Overview

Introduction

ALB version comparison

How it works

Benefits

Application scenarios

Region and Availability Zone

Billing

Getting Started

Creating an ALB instance

Creating a server group and adding backend servers

Creating an HTTP listener

User Guide

Instance

Overview

Creating an instance

Managing an ALB instance

Changing the ALB instance network type

Adding a CNAME record pointing to an instance domain name

Cloning an ALB instance

Listeners

Creating a listener

Creating an HTTP listener

Creating an HTTPS listener

Creating an HTTP/2 listener

Creating a QUIC listener

Custom configuration

Managing a listener

Forwarding rules

Forwarding rule overview

Creating a forwarding rule (Basic edition)

Modifying/Deleting a forwarding rule

Creating a forwarding rule (Standard edition)

Mutual authentication

Adding multiple certificates to an HTTPS listener (Basic edition)

Adding multiple certificates to an HTTPS listener (Standard edition)

Using certificates from Certificate Center

Server groups

Overview

Creating and managing a server group

Configuring security groups of backend servers

Adding secondary network interfaces as backend servers

Cookie-based session persistence

Cross-zone load balancing

Configuring the slow start

Load balancing algorithms

Manage certificates

Overview

Converting certificate formats

Adding/Deleting a certificate

Replacing a certificate

Health check

Security management

Access control

Logs and monitoring

Access log delivery to TOS

Access log delivery to TLS

Data insight

Health check logs

Data Monitoring

Application of ALB in VKE

ALB Ingress overview

Using ALB Ingress via the console

Resource management

User management

Overview

Using an IAM user to access ALB

Configuration examples of ALB custom policies

Project-based management

Overview

Managing an ALB resource by project

Tag-based management

Overview

Managing an ALB resource by tag

API Reference

ALB Instance

CreateLoadBalancer - Creating an ALB instance

DeleteLoadBalancer - Deleting an ALB instance

ModifyLoadBalancerAttributes - Modifying an ALB instance

DescribeLoadBalancers - Querying an ALB instance

DescribeLoadBalancerAttributes - Querying the details of ALB instances

ModifyLoadBalancerType - Changing the ALB instance network type

ModifyLoadBalancerZones - Changing the ALB instance availability zone

LoadBalancerJoinSecurityGroup - Adding an ALB instance to security groups

LoadBalancerLeaveSecurityGroup - Removing an ALB instance from security groups

Availability Zone

DescribeZones - Querying the ALB supported AZ List

Listener

CreateListener - Creating a listener

DeleteListener - Deleting a listener

ModifyListenerAttributes - Modifying the specified listener

DescribeListeners - Querying a listener list

DescribeListenerAttributes - Querying the details of specified listener

DescribeListenerHealth - Querying the health check information of backend servers for a listener

server group

CreateServerGroup - Creating a server group

DeleteServerGroup - Deleting a server group

DescribeServerGroups - Querying a server group list

DescribeServerGroupAttributes - Querying the server group details

ModifyServerGroupAttributes - Modifying the specified server group details

AddServerGroupBackendServers - Adding the backend servers to a specified server group

ModifyServerGroupBackendServers - Modifying a backend server within the specified server group

RemoveServerGroupBackendServers - Removing a backend server from the specified server group

DescribeServerGroupBackendServers - Querying the backend server information of server groups

Health Check Template

CreateHealthCheckTemplates - Creating a health check template

DeleteHealthCheckTemplates - Deleting the health check template

DescribeHealthCheckTemplates - Getting the health check template list

ModifyHealthCheckTemplatesAttributes - Modifying the health check template attributes

forwarding rules

CreateRules - Adding the forwarding rules to a listener

DeleteRules - Deleting the specified listener forwarding rule

DescribeRules - Getting a forwarding rule list of the specified listener

ModifyRules - Modifying the specified listener forwarding rule

certificate

UploadCertificate - Uploading a server certificate

DeleteCertificate - Deleting an unassociated server certificate

DescribeCertificates - Querying the server certificate list

ModifyCertificateAttributes - Modifying the server certificate attributes

ReplaceCertificate - Replacing a server certificate

UploadCACertificate - Uploading a CA Certificate

DeleteCACertificate - Deleting an unassociated CA certificate

DescribeCACertificates - Querying a CA certificate list

ModifyCACertificateAttributes - Modifying the CA certificate attributes

ReplaceCACertificate - Replacing a CA certificate

DescribeAllCertificates - Querying all certificate lists

access log interface

Access Log Delivery TOS

EnableAccessLog - Enabling an access log

DisableAccessLog - Disabling the access log

Access Log Delivery TLS

EnableTLSAccessLog - Enabling an access log delivery to TLS

DisableTLSAccessLog - Disabling an access log delivery to TLS

Health Check Log

EnableHealthLog - Enabling the health check log collection

DisableHealthLog - Disabling the health check log collection

access control

CreateAcl - Creating an ACL

DeleteAcl - Deleting an ACL

ModifyAclAttributes - Modifying the specified ACL

DescribeAcls - Querying an ACL

DescribeAclAttributes - Querying the details of the specified ACL

AddAclEntries - Adding the IP entries to a specified ACL

RemoveAclEntries - Deleting the IP entries from the specified ACL

personalized configuration

CreateCustomizedCfg - Creating a custom configuration

DeleteCustomizedCfg - Deleting a custom configuration

ModifyCustomizedCfgAttributes - Modifying the specified custom configuration

DescribeCustomizedCfgs - Querying the custom configuration list

DescribeCustomizedCfgAttributes - Querying the details of a specified custom configuration

label

TagResources - Adding the custom tags to resources

UntagResources - Deleting a custom tag from resources

ListTagsForResources - Querying the resource tag list

Best Practices

Attaching a cross-VPC backend server to an ALB

Obtaining client source IP via backend server

Integrating ALB with GTM to enable cross-region traffic scheduling and disaster recovery failover

Implementing IPv4 and IPv6 traffic load balancing via ALB

Accessing an ALB across VPCs via PrivateLink

FAQs

Classic Load Balancer (CLB)

Overview

What is a Classic Load Balancer

Features

Product specifications

Benefits

Traffic path description

Application scenarios

Limits

Regions and Availability Zones

Product billing

Billing Method

Changing the billing method

Arrears description

Instructions on expiration

Renewal

Unsubscription description

Instructions on taxes

Quick Start

Planning and preparation

Layer-4 CLB

Quick start

Creating a CLB instance

Configuring a backend server group

Creating a listener

Verifying the CLB service

Layer-7 CLB

Quick start

Creating a CLB instance

Configuring a backend server group

Creating a listener

Configuring a forwarding rule

Verifying the CLB service

User Guide

CLB instances

Creating a CLB instance

Viewing the CLB details

Changing the instance type

Editing the modification protection

IPv4/IPv6 network type conversion

Allowing backend security group

Public CLB to private CLB

Deleting a CLB instance

Public network access

Binding or unbinding an EIP

Managing an IPv6 internet bandwidth

Adding or removing an EIP to or from the Bandwidth Package

Modifying an internet bandwidth limit

Backend Server Group

Server group overview

Creating a server group

Adding or removing a backend server

Modifying the server group

Configuring a backend server security group

Configuring the secondary network interface routing

Deleting a backend server group

Listener

Listener overview

Creating a listener

Creating a TCP protocol listener

Creating a UDP protocol listener

Creating a HTTP listener

Creating an HTTPS listener

Modifying a listener

Starting/Stopping a listener

Deleting a listener

Configuring a forwarding rule

Forwarding rule description

Adding a forwarding rule

Modifying a forwarding rule

Deleting a forwarding rule

Health check

Health check overview

Editing health check

Viewing the health check status

Certificate management

Certificate overview

Uploading a certificate

Modifying the listener certificate

Adding/Deleting an additional certificate

Deleting a certificate

Logs and monitoring

Access log

Access log overview

Access log delivery to TLS

Access log delivery to TOS

Health check log

Health check log overview

Authorizing the cross-service access and creating a log project

Creating a log topic

Viewing the health check log

Monitoring

Viewing monitoring data

Configuring an alert policy

Access control

Access Control Lists overview

Managing the ACL

ACL for listeners

Identity and Access Management

IAM overview

CLB IAM policy types

Custom policy syntax example for CLB

Projects and Tags

Project management

Tag management

Instance diagnosis and network topology

Best Practices

Creating a static page

Creating an HTTP static page

CLB Security Protection

Building an HTTPS static page

Health check exception troubleshooting guide

Configuration practice of a forwarding rule

Forwarding the traffic based on domain name or URL path

Traffic forwarding with the same domain name but different URL paths

Locating the abnormal backend servers through access logs

Monitoring the traffic usage

Automatically adjusting the number of backend servers with the auto-scaling service

Disaster Recovery Best Practices

Configuring the active and standby availability zones in the same region for CLB disaster recovery

Implement cross-region disaster recovery with GTM

Configuring cookie-based session persistence for a Layer-7 listener

Obtaining the client source IP address

Layer 4 listener obtains client source IP

Getting the client source IP for layer-7 listener

HTTPS listener mutual authentication

API reference

Call methods

CLB instances

CreateLoadBalancer - Creating a CLB

DeleteLoadBalancer - Deleting a CLB

ModifyLoadBalancerAttributes - Modifying the CLB attributes

DescribeLoadBalancers - Querying a CLB list

DescribeLoadBalancerAttributes - Querying the CLB details

DescribeZones - Querying the region information

ConvertLoadBalancerBillingType - Converting the CLB billing methods

RenewLoadBalancer - Renewing a CLB

SetLoadBalancerRenewal - Setting the CLB renewal type

DescribeLoadBalancersBilling - Querying the CLB billing information

Listener

CreateListener - Creating a listener

ModifyListenerAttributes - Modifying the listener attributes

DescribeListeners - Querying a listener list

DescribeListenerAttributes - Querying the details of a listener

DescribeListenerHealth - Querying the backend server health check information for a listener

DeleteListener - Deleting a listener

ModifyListenerDomainExtensions - Managing the additional domains of an HTTPS listener

Backend server group

CreateServerGroup - Creating a backend server group

DeleteServerGroup - Deleting a server group

ModifyServerGroupAttributes - Modifying the server group attributes

DescribeServerGroups - Querying a server group list

DescribeServerGroupAttributes - Querying the server group details

AddServerGroupBackendServers - Adding a backend server

RemoveServerGroupBackendServers - Removing a backend server

ACL

DeleteAcl - Deleting an ACL

CreateAcl - Creating an ACL

DescribeAcls - Queryng an ACL

ModifyAclAttributes - Modifying the ACL attributes

DescribeAclAttributes - Querying the ACL details

AddAclEntries - Adding the ACL entries

RemoveAclEntries - Removing the entries from ACL

Forwarding rule

CreateRules - Creating a forwarding rule

DeleteRules - Deleting a forwarding rule

ModifyRules - Modifying a forwarding rule

DescribeRules - Querying a forwarding rule list

Certificate

UploadCertificate - Uploading a certificate

DeleteCertificate - Deleting a certificate

ModifyCertificateAttributes - Modifying the certificate attributes

DescribeCertificates - Querying a certificate list

Access log (Layer-7)

EnableAccessLog - Enabling the layer 7 access log collection

DisableAccessLog - Disabling the layer 7 access log collection

Health check log

CreateHealthCheckLogProject - Creating a health check log project

DescribeHealthCheckLogProjectAttributes - Querying the log project details of a health check

DeleteHealthCheckLogProject - Deleting a log project of health checks

AttachHealthCheckLogTopic - Attaching the health check log topic

DetachHealthCheckLogTopic - Detaching a log topic

DescribeHealthCheckLogTopicAttributes - Querying the health check log topic information

Tag

TagResources - Adding the tags to resources

UntagResources - Deleting a custom tag

ListTagsForResources - Querying the tag information

SDK Reference

CLB SDK Overview

Viewing an SDK sample code

FAQs

CLB instance FAQs

Listener FAQs

Backend Server Group FAQs

Health Check FAQs

ACL FAQs

Certificate FAQs

Log and monitoring FAQs

Billing FAQs

Load Balancer overview

Troubleshooting

Documentation

Load Balancer

Classic Load Balancer (CLB)

User Guide

Backend Server Group

Adding or removing a backend server

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Backend Server Group

Adding or removing a backend server

Copy page

Download PDF

Adding or removing a backend server

Last updated: 2026.06.12 15:32:48

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