Elastic Network Interface (ENI) refers to the type of virtual network interfaces that can be bound to CVM instances in VPCs. An ENI can be migrated freely between CVM instances within the same VPC and AZ, helping you easily build high-availability clusters, implement low-cost failover, and manage networks in a more refined manner.
CLB real servers can be bound to both CVM and ENI. Specifically, a CLB instance communicates with the real server over the private network, and if multiple CVM instances and ENIs are bound to the CLB instance, access traffic will be forwarded to the private IPs of the CVM instances and ENIs.
The ENI binding feature of CLB is currently in beta test. If you want to use it, please submit a ticket for application.
An ENI must be bound to a CVM instance first before it can be bound to a CLB instance. As a CLB instance only forwards traffic as a load balancer but does not process the business logic, the CVM instance, as a computing resource, is needed to process user requests. Please log in to the ENI Console to bind the required ENI to the CVM instance first.