- What's New
- Function Overview
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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 (Dedicated Load Balancers)
- Permissions
- Product Concepts
- How ELB Works with Other Services
- Change History
- Getting Started
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User Guide
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Load Balancer
- Overview
- Preparations for Creating a Load Balancer
- Creating a Dedicated Load Balancer
- Creating a Shared 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
- Enabling or Disabling a Load Balancer
- 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
- Permissions Management
- Quotas
- Appendix
- Change History
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Load Balancer
- Best Practices
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API Reference
- Before You Start
- API Overview
- Calling APIs
- APIs (V3)
- Examples
- Permissions and Supported Actions
- Appendix
- SDK Reference
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FAQs
- Popular Questions
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ELB Use
- Service Abnormality
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ELB Functionality
- Can ELB Be Used Separately?
- Does ELB Support Persistent Connections?
- Does ELB Support FTP on Backend Servers?
- Can ELB Block DDoS Attacks and Secure Web Code?
- 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?
- Are There Any Restrictions on the Frequency of Access from an IP Address?
- Can ELB Be Used Across Accounts or VPCs?
- Can Backend Servers Access the Ports of a Load Balancer?
- Can I Bind a Public IP Address Purchased from a Third-Party Cloud Provider to My Load Balancer?
- Can Both the Listener and Backend Server Group Use HTTPS?
- Can I Change the VPC and Subnet for My Load Balancer?
- Does ELB Support IPv6 Networks?
- Load Balancing Performance
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Load Balancers
- What Is Quota?
- 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 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 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?
- How Do I Combine ELB and WAF?
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Listeners
- What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
- Can I Bind Multiple Certificates to a Listener?
- Do HTTP and HTTP Listeners Support the X-Forwarded-Host Header?
- 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 Cannot I Add a Listener to a Dedicated Load Balancer?
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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 Distribute Traffic Across Servers That Are Not Provided by Huawei Cloud?
- 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 Long Is the Timeout Duration of Connections Between a Load Balancer and Backend Servers?
- 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?
- How Much Time Is Required for a Load Balancer to Disconnect from Backend Servers After The Servers Are Removed?
- Why Must the Subnet Where the Load Balancer Resides Have at Least 16 Available IP Addresses for Enabling IP as a Backend?
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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
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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
- Billing
- Videos
Show all
Function Overview
- ALL
- Dedicated Load Balancers
- Configuring Hybrid Load Balancing (Dedicated Load Balancers)
- Slow Start (Dedicated Load Balancers)
- xxx-WITH-1-3 (Dedicated Load Balancers)
- QUIC Protocol (Dedicated Load Balancers)
- IPv4/IPv6 Dual Stack (Dedicated Load Balancers)
- HTTPS Support (Dedicated Load Balancers)
- Selecting a NIC When Adding a Backend Server (Dedicated Load Balancers)
- Timeout Duration
- SNI Certificate
- HTTP/2
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Only dedicated load balancers
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Dedicated load balancer is newly launched by Huawei Cloud. It has exclusive use of underlying resources, so that the performance of a dedicated load balancer is not affected by other load balancers. In addition, there are a wide range of specifications available for you to select.
You can create a dedicated load balancer in multiple AZs for higher reliability.
Released in: all regions
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Only dedicated load balancers
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You can add servers in a peer VPC, in a VPC that is in another region and connected through a cloud connection, or in an on-premises data center at the other end of a Direct Connect or VPN connection, by using the server IP addresses. In this way, incoming traffic can be flexibly distributed to cloud servers and on-premises servers for hybrid load balancing.
Note the following when you enable hybrid load balancing:
- Enable the IP as a Backend option when you create a dedicated load balancer. If you want to enable this option for an existing dedicated load balancer, go to its Basic Information page.
- You cannot disable the IP as a Backend option after a dedicated load balancer is created. You can use only IPv4 addresses to add IP as Backend Servers.
- Only TCP, HTTP, and HTTPS listeners support hybrid load balancing. Security group rules of IP as Backend Servers must allow traffic from the backend subnets of the load balancer. Otherwise, health checks will fail.
- Source IP addresses of the clients cannot be passed to IP as Backend Servers. Install the TOA module to obtain source IP addresses.
Released in: all regions
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Only dedicated load balancers
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You can enable slow start for HTTP and HTTPS listeners. After you enable it, 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. Slow start ensures that applications start smoothly and can respond to requests with optimal performance. When health checks are enabled, slow start takes effect after backend servers are declared healthy.
Backend servers will exit slow start in either of the following cases:
- The slow start duration elapses.
- The servers become unhealthy during the slow start duration.After an unhealthy backend server exits slow start, it will once again enter slow start after it is detected as healthy.
Released in: all regions
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Only dedicated load balancers
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Two security policies are available for you to select when you create an HTTPS listener for a dedicated load balancer: TLS-1-0-WITH-1-3 and TLS-1-2-FS-WITH-1-3. The two security policies support TLS 1.3, helping you improve security.
Released in: all regions
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Only dedicated load balancers
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If you add a UDP listener to a dedicated load balancer, you can select Quick UDP Internet Connection (QUIC) for the associated backend server group. In this way, you can use the connection ID algorithm to route requests with the same connection ID to the same backend server. QUIC features low latency and high reliability, does not cause head-of-line blocking, and is ideal for mobile Internet. In addition, no new connections need to be established when you switch between a Wi-Fi and a mobile network.
Released in: all regions
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Only dedicated load balancers
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You can create dedicated load balancers that support either IPv4 or IPv6 or both IPv4 and IPv6.
Released in: all regions
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Only dedicated load balancers
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You can select HTTPS for both your listener and the associated backend server group to verify the validity of requests on your load balancer and backend servers, and to enhance service security. This allows you to enable mutual authentication on the load balancer and backend servers.
Released in: all regions
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Only dedicated load balancers
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When adding a backend server to a dedicated load balancer, you can select a primary NIC or an extension NIC to forward traffic.
Released in: all regions
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Both shared and dedicated load balancers
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You can configure and modify timeout durations (idle timeout, request timeout, and response timeout) for your listeners. For example, if the size of a request from an HTTP or HTTPS client is too large, you can increase the request timeout duration to ensure that the request can be routed successfully.
For shared load balancers, you can change only the timeout durations of TCP, HTTP, and HTTPS listeners, but not UDP listeners. For dedicated load balancers, you can change the timeout durations of TCP, UDP, HTTP, and HTTPS listeners.
Released in: all regions
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Both shared and dedicated load balancers
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Server Name Indication (SNI) is an extension to TLS and is used when a server uses multiple domain names and certificates. You can enable SNI if your applications allow access through multiple domain names and each domain name uses an independent certificate. For example, a single IP address is mapped to multiple domain names.
After you enable SNI, the client can submit the requested domain name at the start of the SSL handshake. After receiving the request, the load balancer searches for the certificate based on the domain name. If the certificate is found, the load balancer will return it to the client. If the certificate is not found, the load balancer will return the default certificate. You can enable SNI only when you add HTTPS listeners. Load balancers can have multiple SNI certificates bound.
Released in: All regions
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Both shared and dedicated load balancers
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Hypertext Transfer Protocol 2.0 (HTTP/2) is a new version of the HTTP protocol. HTTP/2 improves the connections between clients and load balancers. You can enable or disable HTTP/2 for an existing HTTPS listener.
HTTP/2 takes effect only for the connections between the clients and your load balancer. HTTP1.x can be used for connections between your load balancer and backend servers.
Released in: All regions
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