You can attach an ENI when creating an ECS instance in the ECS console. For more information about instance creation, see create an instance. This document focuses on the notes for attaching an ENI during ECS instance creation.

Note the following configurations when attaching an ENI during ECS instance creation:

  • Basic configurations:
    • Region: ENIs are supported in all regions.
    • Instance type: Select an instance type that supports ENI. The selected instance type must be I/O optimized.
    • Image: Only the following types of image can automatically recognize ENIs without any additional configuration. For other images, you must configure the ENI to enable the created instance to recognize it.
      • Centos 7.3 64-bit
      • Centos 6.8 64-bit
      • Windows Server 2016 Data Center Edition 64-bit
      • Windows Server 2012 R2 Data Center Edition 64-bit
    • Networking:
      • Network: Select VPC, and then select a created VPC and a VSwitch.
      • ENI: Click Add ENI to attach an ENI, and then select a VSwitch for the ENI.
        Note
        • You are only allowed to attach a maximum of two ENIs when creating an instance in the console. One of them is the primary ENI, which is attached automatically, and the other one is a secondary ENI.
        • After the instance is started, you can attach more secondary ENIs to the instance based on the instance type in the console or by using the AttachNetworkInterface API.

If you want to keep the secondary ENI that is created in this way, detach it from the instance before you release the instance.