Tenant Cloud Network Cloud Load Balancer Operation Guide

Binding Elastic Network Interface

Last Updated At: 2025-11-26 10:18:37

Introduction to ENI

Elastic Network Interface (ENI) is a virtual network interface that can be bound to a CVM instance in a virtual private cloud. Elastic network interface can be freely migrated between CVMs in the same virtual private cloud and availability zone. Elastic network interface can be used to build high-availability clusters, perform low-cost failover, and implement refined network management.
The backend service of CLB supports CVM and ENI, that is, CLB supports binding CVM and ENI. CLB uses private network communication with backend services. When CLB is bound to multiple CVMs and ENIs, access traffic will be forwarded to the private network IP of the CVM and the private network IP of the ENI.

Prerequisites

The ENI must first be bound to a specific CVM before the CLB can bind to that ENI. The CLB only forwards traffic and does not handle business logic, so you need CVM instances to process user requests. Please go to the VPC Console to bind the required ENI to a Cloud Host.

Operation step

  1. You need to configure the CLB listener first. For details, see CLB listener overview.
  2. Click the created listener, expand the domain name and URL path, select the specific URL path, and view the bound backend service on the right side of the listener.
  3. Click Bind, select the backend server to be bound in the pop-up box, and configure the service port and weight. When binding the backend service, you can select Cloud Virtual Machine or Elastic Network Interface.
    • CVM: You can bind the primary private network IP address of the primary network card of all CVMs in the same private network as CLB.
    • ENI: You can bind all ENI IP addresses in the same virtual private cloud as the CLB, except for the primary private network IP of the CVM's primary ENI, such as the secondary private network IP of the primary ENI and the private network IP of the secondary ENI. For details on ENI IP types, see ENI-Related Concepts.

      Description:

      IPv4 CLB supports binding to CVMs or ENIs.


4. Click OK to complete the binding of the backend ENI.