- What's New
- Function Overview
-
Service Overview
- ELB Infographics
- What Is ELB?
- ELB Advantages
- How ELB Works
- Application Scenarios
- Differences Between Dedicated and Shared Load Balancers
- Load Balancing on a Public or Private Network
- Network Traffic Paths
- Specifications of Dedicated Load Balancers
- Notes and Constraints
- Security
- Permissions
- Product Concepts
- ELB and Other Services
-
Billing
- Billing Overview
- Billing Mode
- Billing Items (Dedicated Load Balancers)
- Billing Items (Shared Load Balancers)
- Billing Examples
- Bills
- Arrears
- Stopping Billing
- Cost Management
-
FAQs
- When Do I Need Public Bandwidth for ELB?
- Will I Be Billed for Both the Bandwidth Used by the Load Balancer and the Bandwidth Used by Backend Servers?
- Do I Need to Adjust the Bandwidth of Shared Load Balancers Based on the Bandwidth Used by Backend Servers?
- Can I Modify the Bandwidth of a Load Balancer?
- What Functions Will Become Unavailable If a Load Balancer Is Frozen?
- Getting Started
-
User Guide
-
User Guide for Dedicated Load Balancers
- Using a Dedicated Load Balancer
- Permissions Management
-
Load Balancer
- Dedicated Load Balancer Overview
- Creating a Dedicated Load Balancer
- Enabling or Disabling Modification Protection for Dedicated Load Balancers
- Modifying the Basic Configurations of a Dedicated Load Balancer
- Modifying the Network Configurations of a Dedicated Load Balancer
- Exporting Dedicated Load Balancers
- Deleting a Dedicated Load Balancer
- Copying a Dedicated Load Balancer
- Enabling or Disabling a Load Balancer
- Listener
- Backend Server Group
- Backend Server
- Health Check
- Security
- Access Logging
- Tags and Quotas
- Cloud Eye Monitoring
- Auditing
-
User Guide for Shared Load Balancers
- Permissions Management
-
Load Balancer
- Shared Load Balancer Overview
- Creating a Shared Load Balancer
- Configuring Modification Protection for Shared Load Balancers
- Changing the Network Configurations of a Shared Load Balancer
- Deleting a Shared Load Balancer
- Enabling or Disabling a Shared Load Balancer
- Enabling Guaranteed Performance for a Shared Load Balancer
- Listener
- Backend Server Group
- Backend Server
- Health Check
- Security
- Access Logging
- Tags and Quotas
- Cloud Eye Monitoring
- Auditing
- Self-service Troubleshooting
- Appendix
-
User Guide for Dedicated Load Balancers
-
Best Practices
- Using IP as a Backend to Route Traffic Across Backend Servers
- Using Advanced Forwarding for Application Iteration
- Integrating WAF with ELB to Protect Your Websites
- Configuring HTTPS Mutual Authentication to Improve Service Security
- Using ELB to Redirect HTTP Requests to an HTTPS Listener for Higher Service Security
-
API Reference
- Before You Start
- API Overview
- Calling APIs
-
APIs (V3)
- API Version
- Quota
- AZ
- Load Balancer Flavor
- Reserved IP Address
-
Load Balancer
- Creating a Load Balancer
- Querying Load Balancers
- Viewing Details of a Load Balancer
- Updating a Load Balancer
- Deleting a Load Balancer
- Deleting a Load Balancer and Its Associated Resources
- Querying the Status Tree of a Load Balancer
- Deploying a Load Balancer in Other AZs
- Removing a Load Balancer from AZs
- Certificate
- Security Policy
- IP Address Group
- Listener
- Backend Server Group
- Backend Server
- Health Check
- Forwarding Policy
- Forwarding Rule
- Active/Standby Backend Server Group
- Log
- API (V2)
-
API (OpenStack API)
-
Tag
- Adding a Tag to a Load Balancer
- Batch Adding Load Balancer Tags
- Batch Deleting Load Balancer Tags
- Querying All Tags of a Load Balancer
- Querying the Tags of All Load Balancers
- Querying Load Balancers by Tag
- Deleting a Tag from a Load Balancer
- Adding a Tag to a Listener
- Batch Adding Tags to a Listener
- Batch Deleting Tags from a Listener
- Querying All Tags of a Listener
- Querying the Tags of All Listeners
- Querying Listeners by Tag
- Deleting a Tag from a Listener
- Status Codes
-
Tag
- Examples
- Permissions and Supported Actions
- Appendix
-
Historical APIs
- Shared Load Balancer APIs (OpenStack)
- Asynchronous Job Query
- Querying Versions
-
Getting Started
- Creating a Load Balancer
- Obtaining a Token
- Creating a Load Balancer
- Creating a Public Network Load Balancer
- Adding a Listener
- Creating a Backend Server Group
- Adding Backend Servers
- Configuring a Health Check
- Adding a Forwarding Policy
- Adding a Forwarding Rule
- Adding a Whitelist
- Creating an SSL Certificate
- Cascade Delete
- SDK Reference
-
FAQs
- Popular Questions
-
Service Abnormality
- Why Can't I Access My Backend Servers Through a Load Balancer?
- Why Does a Server Occasionally Time Out When a Client Access It Through Different Load Balancers or Different Listeners of a Load Balancer?
- What Can I Do If ELB Can't Be Accessed or Traffic Routing is Interrupted?
- How Can I Handle Abnormal Status Codes?
- How Do I Handle Abnormal Request Headers?
- How Do I Check for Traffic Inconsistencies?
- Why Does ELB Fail to Distribute Traffic Evenly?
- How Do I Check If There Is Excessive Access Delay?
- What Do I Do If a Load Balancer Fails a Stress Test?
- How Do I Check If Sticky Sessions Failed to Take Effect?
-
ELB Functionality
- Can Load Balancers Be Used Separately?
- Can ELB Block DDoS Attacks and Secure Web Code?
- What Types of APIs Does ELB Provide? What Are Permissions of ELB?
- Can Backend Servers of a Load Balancer Run Different OSs?
- Can ELB Be Used Across Accounts or VPCs?
- Can a Backend Server Access Its Load Balancer?
- Can Both the Listener and Backend Server Group Use HTTPS?
- Does ELB Support IPv6 Networks?
- How Do I Determine the Server Response Time Based on Monitoring Data and Logs?
- How Can I Transfer the IP Address of a Client?
- What Are the Differences Between Persistent Connections and Sticky Sessions?
- How Do I Test Sticky Sessions Using Linux Curl Commands?
-
Load Balancers
- What Is Quota?
- How Does ELB Distribute Traffic?
- How Can I Configure Load Balancing for Containerized Applications?
- Can I Bind Multiple EIPs to a Load Balancer?
- Why Multiple IP Addresses Are Required When I Create a Dedicated Load Balancer?
- Can Backend Servers Access the Internet Using the EIP of the Load Balancer?
- Do Shared Load Balancers Have Specifications?
- What Is the Difference Between the Bandwidth Defined in Each Specification of a Dedicated Load Balancer and the Bandwidth of an EIP?
- How Do I Combine ELB and WAF?
-
Listeners
- What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
- Will ELB Stop Distributing Traffic Immediately After a Listener Is Deleted?
- Does ELB Have Restrictions on the File Upload Speed and Size?
- Can Multiple Load Balancers Route Requests to One Backend Server?
- How Is WebSocket Used?
- What Are the Three Timeouts of a Listener and What Are the Default Durations?
- Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?
- Why Is There a Security Warning After a Certificate Is Configured for an HTTPS Listener?
- Why Is a Forwarding Policy in the Faulty State?
-
Backend Servers
- Can Backend Servers Access the Internet After They Are Associated with a Load Balancer?
- Can ELB Distribute Traffic Across Servers That Are Not Provided by Huawei Cloud?
- Why Are Backend Servers Frequently Accessed by IP Addresses in 100.125.0.0/16 or 214.0.0.0/8?
- Can ELB Route Traffic Across Regions?
- Does Each Backend Server Need an EIP to Receive Requests from a Public Network Load Balancer?
- How Do I Check the Network Conditions of a Backend Server?
- How Can I Check the Network Configuration of a Backend Server?
- How Do I Check the Status of a Backend Server?
- How Do I Check Whether a Backend Server Can Be Accessed Through an EIP?
- Why Is the Number of Active Connections Monitored by Cloud Eye Different from the Number of Connections Established with the Backend Servers?
- Why Can I Access Backend Servers After a Whitelist Is Configured?
- When Will the Changes to Server Weights Be Applied?
-
Health Checks
- How Do I Troubleshoot an Unhealthy Backend Server of a Dedicated Load Balancer?
- How Do I Troubleshoot an Unhealthy Backend Server of a Shared Load Balancer?
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from the Configured Interval?
- How Does ELB Perform UDP Health Checks? What Are the Precautions for UDP Health Checks?
- Why Does ELB Frequently Send Requests to Backend Servers During Health Checks?
- When Does a Health Check Start?
- What Do I Do If a Lot of Access Logs Are Generated During Health Checks?
- What Status Codes Will Be Returned If Backend Servers Are Identified as Healthy?
- Certificates
- Access Logging
- Monitoring
-
Billing
- When Do I Need Public Bandwidth for ELB?
- Will I Be Billed for Both the Bandwidth Used by the Load Balancer and the Bandwidth Used by Backend Servers?
- Do I Need to Adjust the Bandwidth of Shared Load Balancers Based on the Bandwidth Used by Backend Servers?
- Can I Modify the Bandwidth of a Load Balancer?
- What Functions Will Become Unavailable If a Load Balancer Is Frozen?
- Videos
- Glossary
-
More Documents
-
User Guide (ME-Abu Dhabi Region)
- Service Overview
- Load Balancer
- Listener
- Backend Server
- Health Check
- Certificate
- Access Logging
- Monitoring
- Auditing
-
FAQs
- Questions Summary
- ELB Usage
- Load Balancer
- Listener
-
Backend Server
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Is Different from the Configured Health Check Interval?
- Can Backend Servers Access the Public Network After They Are Associated with a Load Balancer?
- How Can I Check the Network Conditions of a Backend Server?
- How Can I Check the Network Configuration of a Backend Server?
- How Can I Check the Status of a Backend Server?
- When Is a Backend Server Considered Healthy?
- Health Check
- Obtaining Source IP Addresses
- HTTP/HTTPS Listeners
- Sticky Session
- Appendix
- Change History
-
API Reference (ME-Abu Dhabi Region)
- Before You Start
- API Overview
- Calling APIs
- Getting Started
- Load Balancer APIs
- Load Balancer (Enterprise Project) APIs
- Common Parameters
- Appendix
- Change History
-
User Guide (Paris Region)
-
Service Overview
- What Is ELB?
- Product Advantages
- How ELB Works
- Application Scenarios
- Differences Between Dedicated and Shared Load Balancers
- Load Balancing on a Public or Private Network
- Network Traffic Paths
- Specifications of Dedicated Load Balancers
- Quotas and Constraints
- Billing (Shared Load Balancers)
- Billing (Dedicated Load Balancers)
- Permissions
- Product Concepts
- How ELB Works with Other Services
- Getting Started
-
Load Balancer
- Overview
- Preparations for Creating a Load Balancer
- Creating a Dedicated Load Balancer
- Creating a Shared Load Balancer
- Configuring Deletion Protection for Load Balancers
- Modifying the Bandwidth
- Changing the Specifications of a Dedicated Load Balancer
- Changing an IP Address
- Binding an IP Address to or Unbinding an IP Address from a Load Balancer
- Adding to or Removing from an IPv6 Shared Bandwidth
- Exporting the Load Balancer List
- Deleting a Load Balancer
- Listener
- Advanced Features of HTTP/HTTPS Listeners
- Backend Server Group
- Backend Server (Dedicated Load Balancers)
- Backend Server (Shared Load Balancers)
- Certificate
- Access Control
- TLS Security Policy
- Tag
- Access Logging
- Monitoring
- Auditing
- Load Balancer Migration
- Permissions Management
- Quotas
-
FAQ
- Popular Questions
- Why Can't I Access My Backend Servers Through a Load Balancer?
- What Can I Do If ELB Can't Be Accessed or Traffic Routing is Interrupted?
- How Can I Handle Error Codes?
- Can ELB Be Used Separately?
- Does ELB Support Persistent Connections?
- Does ELB Support FTP on Backend Servers?
- Is an EIP Assigned Exclusively to a Load Balancer?
- How Many Load Balancers and Listeners Can I Have?
- What Types of APIs Does ELB Provide? What Are Permissions of ELB?
- Can I Adjust the Number of Backend Servers When a Load Balancer is Running?
- Can Backend Servers Run Different OSs?
- Can I Configure Different Backend Ports for a Load Balancer?
- Can ELB Be Used Across Accounts or VPCs?
- Can Backend Servers Access the Ports of a Load Balancer?
- Can Both the Listener and Backend Server Group Use HTTPS?
- Can I Change the VPC and Subnet for My Load Balancer?
- Can I Upgrade a Shared Load Balancer to a Dedicated Load Balancer Without Interrupting Traffic Routing?
- Does ELB Support IPv6 Networks?
- How Do I Check for Traffic Inconsistencies?
- How Do I Check If Traffic Is Being Evenly Distributed?
- How Do I Check If There Is Excessive Access Delay?
- What Do I Do If a Load Balancer Fails a Stress Test?
-
Load Balancers
- How Does ELB Distribute Traffic?
- How Can I Access a Load Balancer Across VPCs?
- How Can I Configure Load Balancing for Containerized Applications?
- Why Can't I Delete My Load Balancer?
- Do I Need to Configure EIP Bandwidth for My Load Balancers?
- Can I Bind Multiple EIPs to a Load Balancer?
- Why Multiple IP Addresses Are Required When I Create or Enable a Dedicated Load Balancer?
- Why Are Requests from the Same IP Address Routed to Different Backend Servers When the Load Balancing Algorithm Is Source IP Hash?
- Can Backend Servers Access the Internet Using the EIP of the Load Balancer?
- Do Shared Load Balancers Have Specifications?
- Will Traffic Routing Be Interrupted If the Load Balancing Algorithm Is Changed?
- What Is the Difference Between the Bandwidth Included in Each Specification of a Dedicated Load Balancer and the Bandwidth of an EIP?
- How Do I Combine ELB and WAF?
-
Listeners
- What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
- Can I Bind Multiple Certificates to a Listener?
- What HTTP Headers Can I Configure for an HTTP and HTTP Listener?
- Will ELB Stop Distributing Traffic Immediately After a Listener Is Deleted?
- Does ELB Have Restrictions on the File Upload Speed and Size?
- Can Multiple Load Balancers Route Requests to One Backend Server?
- How Is WebSocket Used?
- Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?
- Why Cannot I Add a Listener to a Dedicated Load Balancer?
-
Backend Servers
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from What I Have Configured?
- Can Backend Servers Access the Internet After They Are Associated with a Load Balancer?
- Why Are Backend Servers Frequently Accessed by IP Addresses in 100.125.0.0/16?
- Can ELB Route Traffic Across Regions?
- Does Each Backend Server Need an EIP to Receive Requests from a Public Network Load Balancer?
- How Do I Check the Network Conditions of a Backend Server?
- How Can I Check the Network Configuration of a Backend Server?
- How Do I Check the Status of a Backend Server?
- When Is a Backend Server Considered Healthy?
- How Do I Check Whether a Backend Server Can Be Accessed Through an EIP?
- Why Is the Number of Active Connections Monitored by Cloud Eye Different from the Number of Connections Established with the Backend Servers?
- Why Can I Access Backend Servers After a Whitelist Is Configured?
- When Will Modified Weights Take Effect?
- Why Must the Subnet Where the Load Balancer Resides Have at Least 16 Available IP Addresses for Enabling IP as a Backend?
-
Health Checks
- How Do I Troubleshoot an Unhealthy Backend Server?
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from the Configured Interval?
- How Does ELB Perform UDP Health Checks? What Are the Precautions for UDP Health Checks?
- Why Does ELB Frequently Send Requests to Backend Servers During Health Checks?
- When Does a Health Check Start?
- Do Maximum Retries Include Health Checks That Consider Backend Servers Unhealthy?
- What Do I Do If a Lot of Access Logs Are Generated During Health Checks?
- What Status Codes Will Be Returned If Backend Servers Are Identified as Healthy?
- Obtaining Source IP Addresses
-
HTTP/HTTPS Listeners
- Which Protocol Should I Select for the Backend Server Group When Adding an HTTPS Listener?
- Why Is There a Security Warning After a Certificate Is Configured?
- Why Is a Forwarding Policy in the Faulty State?
- Why Can't I Add a Forwarding Policy to a Listener?
- Why Cannot I Select an Existing Backend Server Group When Adding a Forwarding Policy?
- Sticky Sessions
- Certificates
- Monitoring
- Change History
-
Service Overview
-
API Reference (Paris Region)
- Before You Start
- API Overview
- Calling APIs
- Getting Started
- Dedicated Load Balancer APIs
- Classic Load Balancer APIs
- Enhanced Load Balancer APIs
- Appendix
- Change History
-
User Guide (Kuala Lumpur Region)
- Service Overview
- Getting Started
-
Load Balancer
- Overview
- Preparations for Creating a Load Balancer
- Creating a Dedicated Load Balancer
- Modifying the Bandwidth
- Changing the Specifications of a Dedicated Load Balancer
- Changing an IP Address
- Binding an IP Address to or Unbinding an IP Address from a Load Balancer
- Adding to or Removing from an IPv6 Shared Bandwidth
- Exporting the Load Balancer List
- Deleting a Load Balancer
- Listener
- Advanced Features of HTTP/HTTPS Listeners
- Backend Server Group
- Backend Server
- Certificate
- Access Control
- Access Logging
- Monitoring
- Auditing
- Quotas
-
FAQ
- Popular Questions
- Service Abnormality
-
ELB Functionality
- Can ELB Be Used Separately?
- Does ELB Support Persistent Connections?
- Does ELB Support FTP on Backend Servers?
- Is an EIP Assigned Exclusively to a Load Balancer?
- How Many Load Balancers and Listeners Can I Have?
- What Types of APIs Does ELB Provide? What Are Permissions of ELB?
- Can I Adjust the Number of Backend Servers When a Load Balancer is Running?
- Can Backend Servers Run Different OSs?
- Can I Configure Different Backend Ports for a Load Balancer?
- Can ELB Be Used Across Accounts or VPCs?
- Can Backend Servers Access the Ports of a Load Balancer?
- Can Both the Listener and Backend Server Group Use HTTPS?
- Can I Change the VPC and Subnet for My Load Balancer?
- Load Balancing Performance
-
Load Balancers
- How Does ELB Distribute Traffic?
- How Can I Access a Load Balancer Across VPCs?
- Do I Need to Configure EIP Bandwidth for My Load Balancers?
- Can I Bind Multiple EIPs to a Load Balancer?
- Why Multiple IP Addresses Are Required When I Create or Enable a Dedicated Load Balancer?
- Why Are Requests from the Same IP Address Routed to Different Backend Servers When the Load Balancing Algorithm Is Source IP Hash?
- Can Backend Servers Access the Internet Using the EIP of the Load Balancer?
- Will Traffic Routing Be Interrupted If the Load Balancing Algorithm Is Changed?
- What Is the Difference Between the Bandwidth Included in Each Specification of a Dedicated Load Balancer and the Bandwidth of an EIP?
-
Listeners
- What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
- Can I Bind Multiple Certificates to a Listener?
- Will ELB Stop Distributing Traffic Immediately After a Listener Is Deleted?
- Does ELB Have Restrictions on the File Upload Speed and Size?
- Can Multiple Load Balancers Route Requests to One Backend Server?
- How Is WebSocket Used?
- Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?
- Why Cannot I Add a Listener to a Dedicated Load Balancer?
-
Backend Servers
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from What I Have Configured?
- Can Backend Servers Access the Internet After They Are Associated with a Load Balancer?
- Can ELB Route Traffic Across Regions?
- Does Each Backend Server Need an EIP to Receive Requests from a Public Network Load Balancer?
- How Do I Check the Network Conditions of a Backend Server?
- How Can I Check the Network Configuration of a Backend Server?
- How Do I Check the Status of a Backend Server?
- When Is a Backend Server Considered Healthy?
- Why Can I Access Backend Servers After a Whitelist Is Configured?
- When Will Modified Weights Take Effect?
- Why Must the Subnet Where the Load Balancer Resides Have at Least 16 Available IP Addresses for Enabling IP as a Backend?
-
Health Checks
- How Do I Troubleshoot an Unhealthy Backend Server?
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from the Configured Interval?
- How Does ELB Perform UDP Health Checks? What Are the Precautions for UDP Health Checks?
- Why Does ELB Frequently Send Requests to Backend Servers During Health Checks?
- When Does a Health Check Start?
- Do Maximum Retries Include Health Checks That Consider Backend Servers Unhealthy?
- What Do I Do If a Lot of Access Logs Are Generated During Health Checks?
- What Status Codes Will Be Returned If Backend Servers Are Identified as Healthy?
- Obtaining Source IP Addresses
-
HTTP/HTTPS Listeners
- Which Protocol Should I Select for the Backend Server Group When Adding an HTTPS Listener?
- Why Is There a Security Warning After a Certificate Is Configured?
- Why Is a Forwarding Policy in the Faulty State?
- Why Can't I Add a Forwarding Policy to a Listener?
- Why Cannot I Select an Existing Backend Server Group When Adding a Forwarding Policy?
- Sticky Sessions
- Certificates
- Monitoring
- Change History
-
API Reference (Kuala Lumpur Region)
- Before You Start
- API Overview
- Calling APIs
- APIs
- Permissions Policies and Supported Actions
- Appendix
- Historical APIs
- Change History
-
User Guide (Ankara Region)
- Service Overview
- Load Balancer
- Listener
- Advanced Features of HTTP/HTTPS Listeners
- Backend Server Group
- Backend Server
- Certificate
- Access Control
- TLS Security Policy
- Access Logging
- Monitoring
- Quotas
-
FAQ
- Popular Questions
-
ELB Functionality
- Can ELB Be Used Separately?
- Does ELB Support Persistent Connections?
- Does ELB Support FTP on Backend Servers?
- Is an EIP Assigned Exclusively to a Load Balancer?
- How Many Load Balancers and Listeners Can I Have?
- What Types of APIs Does ELB Provide? What Are Permissions of ELB?
- Can I Adjust the Number of Backend Servers When a Load Balancer is Running?
- Can Backend Servers Run Different OSs?
- Can I Configure Different Backend Ports for a Load Balancer?
- Can ELB Be Used Across Accounts or VPCs?
- Can Backend Servers Access the Ports of a Load Balancer?
- Can Both the Listener and Backend Server Group Use HTTPS?
- Can I Change the VPC and Subnet for My Load Balancer?
-
Load Balancers
- How Does ELB Distribute Traffic?
- How Can I Access a Load Balancer Across VPCs?
- Do I Need to Configure EIP Bandwidth for My Load Balancers?
- Can I Bind Multiple EIPs to a Load Balancer?
- Why Multiple IP Addresses Are Required When I Create or Enable a Dedicated Load Balancer?
- Why Are Requests from the Same IP Address Routed to Different Backend Servers When the Load Balancing Algorithm Is Source IP Hash?
- Can Backend Servers Access the Internet Using the EIP of the Load Balancer?
- Will Traffic Routing Be Interrupted If the Load Balancing Algorithm Is Changed?
- What Is the Difference Between the Bandwidth Included in Each Specification of a Dedicated Load Balancer and the Bandwidth of an EIP?
-
Listeners
- What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
- Can I Bind Multiple Certificates to a Listener?
- Will ELB Stop Distributing Traffic Immediately After a Listener Is Deleted?
- Does ELB Have Restrictions on the File Upload Speed and Size?
- Can Multiple Load Balancers Route Requests to One Backend Server?
- How Is WebSocket Used?
- Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?
- Why Cannot I Add a Listener to a Dedicated Load Balancer?
-
Backend Servers
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from What I Have Configured?
- Can Backend Servers Access the Internet After They Are Associated with a Load Balancer?
- Can ELB Route Traffic Across Regions?
- Does Each Backend Server Need an EIP to Receive Requests from a Public Network Load Balancer?
- How Do I Check the Network Conditions of a Backend Server?
- How Can I Check the Network Configuration of a Backend Server?
- How Do I Check the Status of a Backend Server?
- When Is a Backend Server Considered Healthy?
- Why Can I Access Backend Servers After a Whitelist Is Configured?
- When Will Modified Weights Take Effect?
- Why Must the Subnet Where the Load Balancer Resides Have at Least 16 Available IP Addresses for Enabling IP as a Backend?
-
Health Checks
- How Do I Troubleshoot an Unhealthy Backend Server?
- Why Is the Interval at Which Backend Servers Receive Health Check Packets Different from the Configured Interval?
- How Does ELB Perform UDP Health Checks? What Are the Precautions for UDP Health Checks?
- Why Does ELB Frequently Send Requests to Backend Servers During Health Checks?
- When Does a Health Check Start?
- Do Maximum Retries Include Health Checks That Consider Backend Servers Unhealthy?
- What Do I Do If a Lot of Access Logs Are Generated During Health Checks?
- What Status Codes Will Be Returned If Backend Servers Are Identified as Healthy?
- Obtaining Source IP Addresses
-
HTTP/HTTPS Listeners
- Which Protocol Should I Select for the Backend Server Group When Adding an HTTPS Listener?
- Why Is There a Security Warning After a Certificate Is Configured?
- Why Is a Forwarding Policy in the Faulty State?
- Why Can't I Add a Forwarding Policy to a Listener?
- Why Cannot I Select an Existing Backend Server Group When Adding a Forwarding Policy?
- Sticky Sessions
- Certificates
- Monitoring
- Change History
-
API Reference (Ankara Region)
- Before You Start
- API Overview
- Calling APIs
- APIs (V3)
- APIs (V2)
-
APIs (OpenStack)
-
Tag
- Adding a Tag to a Load Balancer
- Batch Adding Load Balancer Tags
- Batch Deleting Load Balancer Tags
- Querying All Tags of a Load Balancer
- Querying the Tags of All Load Balancers
- Querying Load Balancers by Tag
- Deleting a Tag from a Load Balancer
- Adding a Tag to a Listener
- Batch Adding Tags to a Listener
- Batch Deleting Tags from a Listener
- Querying All Tags of a Listener
- Querying the Tags of All Listeners
- Querying Listeners by Tag
- Deleting a Tag from a Listener
- Status Codes
-
Tag
- Permissions and Supported Actions
- Appendix
- Change History
-
User Guide (ME-Abu Dhabi Region)
- General Reference
Copied.
Creating a Backend Server Group
Scenario
To route requests, you need to associate at least one backend server group to each listener.
A backend server group can be associated with more than one listener.
You can create a backend server group for a load balancer in any of the ways described in Table 1.
Scenario |
Reference |
---|---|
Creating a backend server group and associating it with a load balancer |
|
Creating a backend server group when adding a listener |
You can add listeners using different protocols by referring to Listener Overview. |
Changing the backend server group associated with the listener |
Notes and Constraints
The backend protocol of the new backend server group must match the frontend protocol of the listener as described in Table 2.
Load Balancer Specification |
Frontend Protocol |
Backend Protocol |
---|---|---|
Network load balancing |
TCP |
TCP |
Network load balancing |
UDP |
|
Network load balancing |
TLS |
|
Application load balancing |
HTTP |
HTTP |
Application load balancing |
HTTPS |
|
Application load balancing |
QUIC |
|
Procedure
- Go to the backend server group list page.
- Click Create Backend Server Group in the upper right corner.
- Configure the routing policy based on Table 3.
Table 3 Parameters required for configuring a routing policy Parameter
Description
Load Balancer Type
Specifies the type of load balancers that can use the backend server group. Select Dedicated.
Load Balancer
Specifies whether to associate a load balancer.
You can associate an existing dedicated load balancer when you create a backend server group or associate one later.
- Associate later
- Associate existing
Forwarding Mode
Specifies the forwarding mode to distribute traffic. There are two options: Load balancing and Active/Standby.
- Load balancing: You can add one or more backend servers to the backend server group.
- Active/Standby: You must add two backend servers to the backend server group, one acting as the active server and the other as the standby server. If the active server is faulty, traffic is forwarded to the standby server, improving service reliability. Active/standby backend server groups can only be associated with TCP, UDP, and TLS listeners.
Backend Server Group Type
Specifies the type of the backend server group.
- Hybrid: You can add ECSs and supplementary network interfaces as backend servers, or add IP addresses as servers when IP as a Backend is enabled.
When you create a hybrid backend server group, you must specify a VPC and associate the backend server group with a load balancer in this VPC.
- IP as a backend server: You can add IP addresses as backend servers only when you enable IP as a Backend.
NOTE:
This option is available in certain regions. You can see which regions support this option on the console.
Backend Server Group Name
Specifies the name of the backend server group.
VPC
Specifies the VPC where the backend server group works. You can associate the backend server group with a load balancer in this VPC.
This parameter is mandatory if you select Hybrid for Backend Server Group Type.
You can select an existing VPC or create a new one.
For more information about VPC, see the Virtual Private Cloud User Guide.
Backend Protocol
Specifies the protocol that backend servers in the backend server group use to receive requests from the listeners. The protocol varies depending on the forwarding mode:
- Load balancing: HTTP, HTTPS, gRPC, TCP, UDP, TLS, or QUIC
- Active/Standby: TCP, UDP, TLS, or QUIC
IP Address Type
Specifies the IP address type of backend servers that can be added to a backend server group. By default, IPv4 addresses can be added as backend servers.
There are two options when the backend protocol is TCP or UDP:
- IPv4: Only IPv4 addresses can be added as backend servers.
- Dual stack: Both IPv4 and IPv6 addresses can be added as backend servers.
NOTE:
This option is available in certain regions. You can see which regions support this option on the console.
Forward to Same Port
If this option is enabled, you do not need to specify a backend port when you add a backend server. The listener routes the requests to the backend server over the same port as the frontend port.
This option cannot be disabled after being enabled.
NOTE:
This option is available in certain regions. You can see which regions support this option on the console.
NOTE:
This option is available only for TCP, UDP, or QUIC backend server groups associated with a dedicated load balancer.
Load Balancing Algorithm
Specifies the algorithm used by the load balancer to distribute traffic. The following options are available:
- Weighted round robin: Requests are routed to different servers based on their weights. Backend servers with higher weights receive proportionately more requests, whereas equal-weighted servers receive the same number of requests.
- Weighted least connections: In addition to the number of connections, each server is assigned a weight based on its capacity. Requests are routed to the server with the lowest connections-to-weight ratio.
- Source IP hash: Allows requests from different clients to be routed based on source IP addresses and ensures that requests from the same client are forwarded to the same server.
- Connection ID: This algorithm is available when you have selected QUIC for Backend Protocol. This algorithm allows requests with different connection IDs to be routed to different backend servers and ensures that requests with the same connection ID are routed to the same backend server.
For more information about load balancing algorithms, see Load Balancing Algorithms.
Forwarding Even Unhealthy
Specifies whether to forward traffic across all the backend servers even if all of them have been identified as unhealthy. This option is only available if Forwarding Mode is set to Load balancing.
This option is disabled by default, preventing requests from being sent to the backend server group, in which all backend servers are identified as unhealthy.
If this option is enabled, ELB forwards traffic across all the backend servers even if all of them have been identified as unhealthy.
The function improves service availability by preventing disruptions from faulty health checks resulting from misconfigurations.
Sticky Session
Specifies whether to enable sticky sessions if you have selected Weighted round robin, Connection ID, or Weighted least connections for Load Balancing Algorithm.
If you enable sticky sessions, all requests from the same client during one session are sent to the same backend server.
For more information about sticky sessions, see Sticky Session.
NOTE:
TLS backend server groups do not support sticky sessions.
Sticky Session Type
Specifies the sticky session type.
This parameter is mandatory if Sticky Session is enabled. You can select one of the following types:
- Source IP address: The source IP address of each request is calculated using the consistent hashing algorithm to obtain a unique hashing key, and all backend servers are numbered. The system allocates the client to a particular server based on the generated key. This allows requests from the same IP address are forwarded to the same backend server.
- Load balancer cookie: The load balancer generates a cookie after receiving a request from the client. All subsequent requests with the cookie are routed to the same backend server.
NOTE:
- Source IP address is available when you have selected TCP, QUIC, or UDP for Backend Protocol.
- Load balancer cookie and Application cookie are available when you have selected HTTP, GRPC, or HTTPS for Backend Protocol.
Stickiness Duration (min)
Specifies the minutes that sticky sessions are maintained. This parameter is mandatory if Sticky Session is enabled.
- Sticky sessions at Layer 4: 1 to 60
- Sticky sessions at Layer 7: 1 to 1440
Slow Start
Specifies whether to enable slow start. This parameter is optional if you have selected Weighted round robin for Load Balancing Algorithm.
After you enable this option, the load balancer linearly increases the proportion of requests to backend servers in this mode.
When the slow start duration elapses, the load balancer sends full share of requests to backend servers and exits the slow start mode.
NOTE:
Slow start is only available for HTTP, gRPC, and HTTPS backend server groups of dedicated load balancers.
For more information about the slow start, see Slow Start.
Slow Start Duration (s)
Specifies how long the slow start will last, in seconds.
This parameter is mandatory if Slow Start is enabled.
Deregistration Delay
This parameter is enabled by default if the backend protocol is TCP, UDP, or QUIC.
If a backend server is removed or the health check fails, ELB continues to route in-flight requests to this server until the deregistration delay timeout expires.
NOTE:
This option is available in certain regions. You can see which regions support this option on the console.
Deregistration Delay Timeout (s)
This parameter is mandatory if Deregistration Delay is enabled.
ELB continues to route in-flight requests to the backend server until the deregistration delay timeout expires.
The value ranges from 10 to 4000, in seconds. The default value is 300.
Description
Provides supplementary information about the backend server group.
- Click Next to add backend servers and configure health check.
Add cloud servers, supplementary network interfaces, or IP addresses to this backend server group. For details, see Backend Server Overview.
Configure health check for the backend server group based on Table 4. For more information about health checks, see Health Check.Table 4 Parameters required for configuring a health check Parameter
Description
Health Check
Specifies whether to enable health checks.
If the health check is enabled, click
next to Advanced Settings to set health check parameters.
Health Check Protocol
Specifies the protocol that will be used by the load balancer to check the health of backend servers.
- TCP, HTTP, TLS, gRPC, and HTTPS are supported.
- If the protocol of the backend server group is UDP and QUIC, the health check protocol is UDP by default and cannot be changed.
NOTE:
TLS and gRPC are available in certain regions. You can see which regions support them on the console.
Domain Name
Specifies the domain name that will be used for health checks.
This parameter is mandatory if the health check protocol is HTTP, gRPC, or HTTPS.
- By default, the private IP address of each backend server is used.
- You can also specify a domain name that consists of at least two labels separated by periods (.). Use only letters, digits, and hyphens (-). Do not start or end strings with a hyphen. Max total: 100 characters. Max label: 63 characters.
Health Check Port
Specifies the port that will be used by the load balancer to check the health of backend servers. The port number ranges from 1 to 65535.
NOTE:
By default, the service port on each backend server is used. You can also specify a port for health checks.
Path
Specifies the health check URL, which is the destination on backend servers for health checks. This parameter is mandatory if the health check protocol is HTTP, gRPC, or HTTPS.
The path can contain 1 to 80 characters and must start with a slash (/).
The path can contain letters, digits, hyphens (-), slashes (/), periods (.), question marks (?), number signs (#), percent signs (%), ampersands (&), and extended character sets _;~!. () *[]@$^:',+
Interval (s)
Specifies the maximum time between two consecutive health checks, in seconds.
The interval ranges from 1 to 50.
Timeout (s)
Specifies the maximum time required for waiting for a response from the health check, in seconds. The value ranges from 1 to 50.
Healthy Threshold
Specifies the number of consecutive successful health checks required for declaring a backend server healthy. The value ranges from 1 to 10.
Unhealthy Threshold
Specifies the number of consecutive failed health checks required for declaring a backend server unhealthy. The value ranges from 1 to 10.
Status Code
Specifies the status codes that will be returned to the load balancer to indicate the health of backend servers. This parameter is available only when you set the health check protocol to HTTP or HTTPS.
You can enter a unique number or a positive number range within the status code range, for example, 0-10 and 200-300. A maximum of five HTTP status codes are supported. If there is more than one status code, press Enter to separate them.
- If the health check protocol is HTTP or HTTPS, the status code ranges from 200 to 599.
- When the gRPC protocol is used, the status code ranges from 0 to 99.
NOTE:
This feature will be available in more regions. See details on the management console.
- Click Next.
- Confirm the specifications and click Create Now.
Related Operations
You can associate the backend server group with the listener of a dedicated load balancer in either way listed in Table 1.
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.
For any further questions, feel free to contact us through the chatbot.
Chatbot