# Add backend service nodes for application load balancing - AddTargets

## Overview

Add backend service nodes to the application load balancer listener






## Definition

### Public Parameters

| Parameter Name | Type | Description Information | Required |
|:---|:---|:---|:---|
| **Action**     | string  | Corresponding API command name, the current API is `AddTargets`.                      | **Yes** |
| **PublicKey**  | string  | The user's public key can be obtained from [Console](https://console.scloudsg.com/uaccount/api_manage)                                             | **Yes** |
| **Signature**  | string  | User signature generated based on public key and API command, see [Signature Algorithm](/docs/api/summary/signature.md)  | **Yes** |

### Request Parameters

| Parameter Name | Type | Description Information | Required |
|:---|:---|:---|:---|
| **Region** | string | Region. See [List of Regions and Availability Zones](/docs/api/summary/regionlist) |**Yes**|
| **ProjectId** | string | Project ID. If not filled in, the default project is used, sub-accounts must be filled in. Please refer to the [GetProjectList interface](/docs/api/summary/get_project_list). |**Yes**|
| **LoadBalancerId** | string | ID of the Load Balancing Instance |**Yes**|
| **ListenerId** | string | Listener's ID |**Yes**|
| **Targets.N.ResourceType** | string | Type of service node. Limited enumeration values: "UHost" / "UNI"/"UPM"/"IP", default value: "UHost"; For non-IP types, if the resource has multiple IPs, only the main IP can be added; For non-IP types, related resource information will be displayed when shown, while IP types only display IP information. When the related resource is deleted, non-IP types will remove the related resource from the load balancer, but this logic is not guaranteed for IP types. |No|
| **Targets.N.ResourceId** | string | Resource ID of the service node. Must be passed when not of IP type. |No|
| **Targets.N.VPCId** | string | The VPC resource ID of the service node. It is required when the IP type is passed. |No|
| **Targets.N.SubnetId** | string | The subnet resource ID of the service node. Must be passed when the IP type is used. |No|
| **Targets.N.ResourceIP** | string | IP of the service node. Must be provided when the IP type is set. |No|
| **Targets.N.Port** | int | Port of the service node. Limited value range: [1-65535], default value is 80 |No|
| **Targets.N.Weight** | int | The weight of the service node. Limited value range: [1-100], default value is 1; only effective in weighted round-robin algorithm. |No|
| **Targets.N.Enabled** | boolean | Is the service node enabled? The default value is true. |No|
| **Targets.N.IsBackup** | boolean | Is the service node a backup node? The default value is false. |No|

### Response Field

| Field Name | Type | Description Information | Required |
|:---|:---|:---|:---|
| **RetCode** | int | Return status code. If it is 0, it means successful return. If it is not 0, it means failure. |**Yes**|
| **Action** | string | Operation command name. |**Yes**|
| **Message** | string | Returns an error message, providing detailed description when `RetCode` is non-zero. |No|
| **Targets** | array[[*TargetSet*](#targetset)] | Service Node Information |No|

#### Data Model


#### TargetSet

| Field Name | Type | Description Information | Required |
|:---|:---|:---|:---|
| **ResourceType** | string | Type of service node. Limited enumeration values: UHost -> Cloud Host, UNI -> Virtual Network Interface, UPM -> Physical Cloud Host, IP -> IP type; Default value: "UHost"; For non-IP types, if the resource has multiple IPs, only the main IP can be added; For non-IP types, related resource information will be displayed during the presentation, while IP type only displays IP information. When the related resource is deleted, the non-IP type will remove the related resources from the lb, but the IP type does not guarantee this logic. |No|
| **ResourceId** | string | Resource ID of the service node. Must be passed when not of IP type. |No|
| **VPCId** | string | The VPC resource ID of the service node. It is required when the IP type is passed. |No|
| **SubnetId** | string | The subnet resource ID of the service node. Must be passed when the IP type is used. |No|
| **ResourceIP** | string | IP of the service node. Must be provided when the IP type is set. |No|
| **Port** | int | Port of the service node. Limited value range: [1-65535]; Default value: 80 |No|
| **Weight** | int | The weight of the service node. Limited value range: [1-100]; Only effective when using the weighted round-robin algorithm; Default value: 1. |No|
| **Enabled** | boolean | Is the service node enabled? Default value: true |No|
| **IsBackup** | boolean | Is the service node a backup node. Default value: false |No|
| **Id** | string | Identification ID of the service node. |No|
| **State** | string | Health check status of the service node. Limited enumeration values: Healthy -> Healthy, Unhealthy -> Unhealthy. |No|

## Example

### Request Example
    
```
https://api.scloudsg.com/?Action=AddTargets
&Region=cn-zj
&Zone=cn-zj-01
&ProjectId=tSIXzLcj
&LoadBalancerId=hWQXJvSD
&ListenerId=dxivFPkq
&Targets.n.ResourceType=rpCZGTgI
&Targets.n.ResourceId=HgfbDNGq
&Targets.n.VPCId=XvDOHmPd
&Targets.n.SubnetId=QQocJvAk
&Targets.n.ResourceIP=pbbYxWoB
&Targets.n.Port=2
&Targets.n.Weight=9
&Targets.n.Enabled=false
&Targets.n.IsBackup=false
&Targets.n.Id=OuqVYQov
```

### Response Example
    
```json
{
  "Action": "AddTargetsResponse",
  "RetCode": 0,
  "Targets": [
    {
      "Enabled": true,
      "Id": "aaRSmiMG",
      "IsBackup": true,
      "Port": 5,
      "ResourceIP": "HOedmGiS",
      "ResourceId": "hyLxeaCA",
      "ResourceType": "xSewdOoe",
      "State": "UBlOVPSH",
      "SubnetId": "FllAtFNO",
      "VPCId": "BdPHyavQ",
      "Weight": 7
    }
  ]
}
```