All Products
Document Center

Elastic Compute Service:AttachNetworkInterface

Last Updated:Apr 11, 2024

Attaches an elastic network interface (ENI) to an Elastic Compute Service (ECS) instance that resides in a virtual private cloud (VPC).

Operation description

Take note of the following items:

  • The ENI must be in the Available state. You can attach an ENI to only one instance that resides in the same zone and VPC as the ENI.``

  • The instance must be in the Running or Stopped state. When you attach ENIs to instances of specific instance types, make sure that the instances are in the Stopped state. For more information, see the "Instance types of the ECS instances that must be in the Stopped (Stopped) state" section in the Bind an ENI topic.


    NoteIf the last start time of the instance (including the start time of the instance if it is a new instance, the last restart time of the instance, and the last reactivation time of the instance) is before April 1st, 2018 and the instance is in the Running state, you must call the RebootInstance operation to restart the instance. If you do not call the RebootInstance operation to restart the instance, you cannot attach the ENI to the instance.

  • You can attach multiple ENIs to one instance. For more information, see ENI overview.

  • The vSwitch to which the ENI is connected must be in the same zone and VPC as the vSwitch to which the instance is connected.

  • This operation is an asynchronous operation. After you call this operation to attach an ENI, you can view the status or events of the ENI to check whether the ENI is attached. The following figure shows the transitions between the statuses of the ENI.

If the ENI is in the Attaching state, the ENI attachment request is sent and the ENI is being attached to the specified instance. If the ENI is in the InUse state, the ENI is attached to the specified instance. If the ENI is in the Available state, the ENI failed to be attached.

**For examples on how to call this operation, see **Attach an ENI.


OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer.

Authorization information

There is currently no authorization information disclosed in the API.

Request parameters


The region ID of the instance. You can call the DescribeRegions operation to query the most recent region list.


The ID of the ENI.


The instance ID.


The ID of the trunk ENI.

Note This parameter is unavailable.
Note This parameter is no longer supported.

The index of the network interface controller (NIC).

Note The value of this parameter varies based on the instance family of the specified instance. If the instance type of the specified instance does not support NICs, leave this parameter empty. If the instance type of the specified instance supports NICs, set this parameter to a valid value. For information about the valid values of this parameter, see Instance families.

Response parameters


The request ID.



Sample success responses


  "RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3C83E"

Error codes

HTTP status codeError codeError messageDescription
400InvalidOperation.Ipv6CountExceededThe number of IPv6 supported by the current instance type has reached the upper limit.-
400MissingParameter%sA parameter is not specified.
400UnsupportedParameter%sThe parameter is not supported.
400InvalidParameter%sThe specified parameter is invalid.
400InvalidInstanceID.Malformed%sThe specified InstanceId parameter is invalid.
400InvalidOperation.InvalidRegion%sThe specified RegionId parameter is invalid.
400InvalidOperation.InvalidEcsStateThe operation is not allowed in the current ECS state.-
400Forbidden.RegionId%sThe service is unavailable in the current region.
400InvalidParams.EniId%sThe specified EniId parameter is invalid.
400InvalidParameter.NetworkCardIndexInvalidInvalid network card index, please check instance type.-
400InvalidOperation.UserNotSupportNetworkCardUser not support network card.-
403InvalidUserType.NotSupported%sYour account does not support this operation.
403Abs.InvalidAccount.NotFound%sYour Alibaba Cloud account does not exist or your AccessKey pair has expired.
403Forbidden.NotSupportRAM%sRAM users are not authorized to perform this operation.
403Forbidden.SubUser%sYou are not authorized to manage this resource. Contact the owner of the Alibaba Cloud account for authorization.
403MaxEniCountExceeded%sThe maximum number of ENIs that can be managed has been reached.
403EniPerInstanceLimitExceeded%sThe maximum number of ENIs that can be attached to the specified instance has been reached.
403InvalidOperation.AvailabilityZoneMismatch%sThe operation is invalid.
403InvalidOperation.VpcMismatch%sThe operation is invalid. Check whether the VPC in the operation corresponds to other parameters.
403InvalidSecurityGroupId.NotVpc%sThe specified SecurityGroupId parameter is invalid and the network type of the security group is not VPC.
403InvalidInstanceId.NotFound%sThe specified instance does not exist. Check whether the InstanceId parameter is valid.
403InvalidEni.NotSameVpc%sThe specified resource and the specified ENI do not belong to the same VPC. For more information, see the return value of the %s placeholder in the error message.
403InvalidOperation.Ipv4CountExceeded%sThe operation is valid because the maximum number of IPv4 addresses has been reached.
403InvalidOperation.EniServiceManaged%sThe operation is invalid.
403InvalidOperation.MultiGroupTypeThe specified instance can't join different types of security group.-
403InvalidOperation.NotSupportEnterpriseGroupThe specified instance type doesn't support enterprise level security group.-
403InvalidOperation.EniCountExceededThe maximum number of eni in a enterprise level security group is exceeded.-
403InvalidOperation.HotPlugNotSupport%sThe operation is not supported while the specified resource is running. For more information, see the return value of the %s placeholder in the error message.
403InvalidOperation.EniTypeNotSupportTrunking%sThe type of the ENI does not support operations related to the trunk mode. For more information, see the return value of the %s placeholder in the error message.
403InvalidParameter.EniNotBelongTrunk%sThe specified ENI is not in trunk mode. For more information, see the return value of the %s placeholder in the error message.
403InvalidOperation.ExceedInstanceTypeQueueNumber%sThe maximum number of queues for all ENIs on an instance has been exceeded. For more information, see the return value of the %s placeholder in the error message.
404InvalidEcsId.NotFound%sThe specified instance ID does not exist.
404InvalidEniId.NotFound%sThe specified ENI ID does not exist.
404InvalidVSwitchId.NotFound%sThe specified vSwitch does not exist.
404InvalidSecurityGroupId.NotFound%sThe specified security group ID does not exist.

For a list of error codes, visit the Service error codes.

Change history

Change timeSummary of changesOperation
2023-01-04The Error code has changed. The request parameters of the API has changedsee changesets
Change itemChange content
Error CodesThe Error code has changed.
    Error Codes 400 change
    delete Error Codes: 403
    delete Error Codes: 404
Input ParametersThe request parameters of the API has changed.
    Added Input Parameters: NetworkCardIndex