> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/api-reference/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/api-reference/compute/zec/vnic/attachnetworkinterface.md).

# AttachNetworkInterface

## 1. API Description

This API (AttachNetworkInterface) is used to attach the vNIC to the instance.

{% hint style="info" %} <mark style="color:blue;">**Note**</mark>

* <mark style="color:blue;">Up to 8 vNICs can be attached per instance.</mark>
* <mark style="color:blue;">vNICs can only be attached to instances in the running state.</mark>
* <mark style="color:blue;">vNIC state must be</mark> <mark style="color:blue;">`AVAILABLE`</mark><mark style="color:blue;">.</mark>
  {% endhint %}

## 2. Input Parameters

The following request parameter list only provides API request parameters.

| Parameter Name | Required | Type   | Description         |
| -------------- | -------- | ------ | ------------------- |
| nicId          | Yes      | String | ID of the vNIC.     |
| instanceId     | Yes      | String | ID of the instance. |

## 3. Output Parameters

| Parameter Name | Type   | Description                                                                                                           |
| -------------- | ------ | --------------------------------------------------------------------------------------------------------------------- |
| requestId      | String | <p>The unique request ID, which is returned for each request.</p><p>RequestId is required for locating a problem.</p> |

## 4. Code Example

{% tabs %}
{% tab title="Example" %}
**Attach the vNIC to the instance.**

```json
POST /api/v2/zec HTTP/1.1
Host: console.zenlayer.com
Content-Type: application/json
X-ZC-Action: AttachNetworkInterface
<Common Request Params>

Request:
{
  "nicId": "XXX",
  "instanceId": "xxx"
}

Response:
{
  "requestId": "TBFC01FCF-6439-4530-ADBC-16809F0C3E8F",
  "response": {
    "requestId": "TBFC01FCF-6439-4530-ADBC-16809F0C3E8F"
  }
}
```

{% endtab %}
{% endtabs %}

## 5. Developer Resources

Zenlayer Cloud API 2.0 integrates [SDKs](/api-reference/api-introduction/toolkit/api-sdk.md)，to make it easier for you to call APIs. More programming languages will be supported.

## 6. Error Codes

The following only lists the error codes related to the API business logic. For other error codes, see [Common Error Codes](/api-reference/api-introduction/instruction/commonerrorcode.md).

| HTTP Status Code | Error Code                                        | Description                                                          |
| ---------------- | ------------------------------------------------- | -------------------------------------------------------------------- |
| 404              | INVALID\_INSTANCE\_NOT\_FOUND                     | Instance not found.                                                  |
| 400              | INVALID\_NIC\_ATTACHED                            | The vNIC has attached to an instance already.                        |
| 409              | INVALID\_NIC\_INSTANCE\_REGION\_MISMATCH          | Instance and vNIC are not in the same zone.                          |
| 404              | INVALID\_NIC\_NOT\_FOUND                          | vNIC does not exist.                                                 |
| 400              | INVALID\_NIC\_STATUS                              | Current vNIC state does not allow this operation.                    |
| 400              | OPERATION\_DENIED\_INSTANCE\_STATUS\_NOT\_SUPPORT | Current instance state does not allow this operation.                |
| 400              | OPERATION\_DENIED\_INSTANCE\_QGA\_NOT\_AVAILABLE  | The QGA instance is unavailable and cannot bind to the network card. |