Elastic Network Interface

Elastic Network Interface (ENI) is an elastic network interface bound to CVMs in a VPC, which can be freely migrated among multiple CVMs. ENI is very helpful in configuring and managing networks and building highly reliable network solutions.
An ENI combines VPC, availability zone, and subnet attributes and can only be bound to CVMs in the same availability zone. A CVM can bind multiple ENIs, and the specific number of bindings will depend on the host specifications.

Relevant Concepts

• Primary NIC and Secondary NIC: The NIC that is created simultaneously with the creation of a CVN in a VPC is the primary NIC, while those NICs created by users are considered secondary NICs. The primary NIC does not support binding or unbinding, while the secondary NICs do support binding and unbinding.
• Primary Private IP Address: The primary private IP address of the ENI is randomly assigned by the system or set by the user when the ENI is created. The primary private IP address of the primary NIC can be modified, but the primary private IP address of the secondary NIC cannot be modified.
• Secondary Private IP Address: The secondary private IP addresses bound to an ENI except the primary IP can be configured by users when creating or editing an ENI, and support binding and unbinding.
• EIP: Bind one by one with the private IP address on the ENI.
• Security Group: An ENI can be bound with one or multiple security groups.
• MAC Address: The ENI has a globally unique MAC address.

Use Cases

• Isolation of Private Network, Public Network, and Management Network:
  The network deployment of important businesses generally requires the isolation of the private network, public network, and management network for data transmission, and ensures data security and network isolation between networks through different routing policies and security group policies. Just like a physical server, you can bind three ENIs in different subnets to the CVM to achieve triple network isolation.
• High-Reliability Application Deployment:
  The key components in the system architecture need to be deployed in a multi-machine hot standby mode to ensure the high availability of the system. Converge Cloud provides ENIs and private IP addresses that can be flexibly bound and unbound. You can configure the disaster recovery settings of Keepalived to achieve high-availability deployment of key components.

API Overview

The following table shows the APIs related to ENI and CVM.