Introduction
Elastic Network Interfaces (ENIs) are elastic network interfaces bound to Cloud Virtual Machines (CVMs) deployed in a Virtual Private Cloud (VPC). ENIs can be freely migrated between CVMs. They significantly help configure and manage networks and develop highly reliable network solutions. You can bind multiple ENIs in the same VPC and availability zone (AZ) to a CVM to implement a high-availability network solution. You can also bind multiple private IP addresses to an ENI to enable multi-IP address deployment on a single host.
Features
Multiple ENIs
When you create a CVM, the primary ENI is automatically generated for the CVM. In addition, you can bind multiple secondary ENIs to the CVM. These ENIs can belong to different subnets in the same VPC and AZ. Each ENI supports the configuration of independent security groups. The subnet where an ENI resides can be configured with independent routing and forwarding policies.
Flexible Migration
ENIs can be freely migrated between CVMs in the same VPC and AZ. When an ENI is unbound from a CVM, the bound private IP addresses, Elastic IPs (EIPs), and security group policies are retained so that you do not need to configure the binding relationships again after migration.
Multiple IP Addresses
Based on the configuration of a CVM, up to 30 private IP addresses can be bound to an ENI, and each private IP address can be bound to an independent EIP. A single CVM can use multiple EIPs to provide multiple ports of the same type. The binding relationships among the ENI, private IP addresses, and EIPs are retained when the ENI is unbound from the CVM.
Independent Routing and Forwarding
ENIs that reside in the same VPC and AZ but across different subnets can be bound to a CVM. You can configure independent routing and forwarding policies for each subnet to isolate networks. You can also configure routing policies in the CVM to direct network traffic destined for specific destination CIDR block to different ENIs.