# ModifyHosts
<a name="API_ModifyHosts"></a>

Modify the auto-placement setting of a Dedicated Host. When auto-placement is enabled, any instances that you launch with a tenancy of `host` but without a specific host ID are placed onto any available Dedicated Host in your account that has auto-placement enabled. When auto-placement is disabled, you need to provide a host ID to have the instance launch onto a specific host. If no host ID is provided, the instance is launched onto a suitable host with auto-placement enabled.

You can also use this API action to modify a Dedicated Host to support either multiple instance types in an instance family, or to support a specific instance type only.

## Request Parameters
<a name="API_ModifyHosts_RequestParameters"></a>

The following parameters are for this specific action. For more information about required and optional parameters that are common to all actions, see [Common Query Parameters](CommonParameters.md).

 **AutoPlacement**   
Specify whether to enable or disable auto-placement.  
Type: String  
Valid Values: `on | off`   
Required: No

 **HostId.N**   
The IDs of the Dedicated Hosts to modify.  
Type: Array of strings  
Required: Yes

 **HostMaintenance**   
Indicates whether to enable or disable host maintenance for the Dedicated Host. For more information, see [Host maintenance](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-hosts-maintenance.html) in the *Amazon EC2 User Guide*.  
Type: String  
Valid Values: `on | off`   
Required: No

 **HostRecovery**   
Indicates whether to enable or disable host recovery for the Dedicated Host. For more information, see [Host recovery](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-hosts-recovery.html) in the *Amazon EC2 User Guide*.  
Type: String  
Valid Values: `on | off`   
Required: No

 **InstanceFamily**   
Specifies the instance family to be supported by the Dedicated Host. Specify this parameter to modify a Dedicated Host to support multiple instance types within its current instance family.  
If you want to modify a Dedicated Host to support a specific instance type only, omit this parameter and specify **InstanceType** instead. You cannot specify **InstanceFamily** and **InstanceType** in the same request.  
Type: String  
Required: No

 **InstanceType**   
Specifies the instance type to be supported by the Dedicated Host. Specify this parameter to modify a Dedicated Host to support only a specific instance type.  
If you want to modify a Dedicated Host to support multiple instance types in its current instance family, omit this parameter and specify **InstanceFamily** instead. You cannot specify **InstanceType** and **InstanceFamily** in the same request.  
Type: String  
Required: No

## Response Elements
<a name="API_ModifyHosts_ResponseElements"></a>

The following elements are returned by the service.

 **requestId**   
The ID of the request.  
Type: String

 **successful**   
The IDs of the Dedicated Hosts that were successfully modified.  
Type: Array of strings

 **unsuccessful**   
The IDs of the Dedicated Hosts that could not be modified. Check whether the setting you requested can be used.  
Type: Array of [UnsuccessfulItem](API_UnsuccessfulItem.md) objects

## Errors
<a name="API_ModifyHosts_Errors"></a>

For information about the errors that are common to all actions, see [Common client error codes](errors-overview.md#CommonErrors).

## Examples
<a name="API_ModifyHosts_Examples"></a>

### Example 1
<a name="API_ModifyHosts_Example_1"></a>

This example enables the auto-placement setting on a Dedicated Host.

#### Sample Request
<a name="API_ModifyHosts_Example_1_Request"></a>

```
https://ec2.amazonaws.com/?Action=ModifyHosts
&AutoPlacement=on
&HostId=h-00548908djdsgfs
&AUTHPARAMS
```

#### Sample Response
<a name="API_ModifyHosts_Example_1_Response"></a>

```
<ModifyHostsResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
    <requestId>d4904fd9-82c2-4ea5-adfe-a9cc3EXAMPLE</requestId>
    <unsuccessful/>
    <successful>
        <item>h-00548908djdsgfs</item>
    </successful>
</ModifyHostsResponse>
```

### Example 2
<a name="API_ModifyHosts_Example_2"></a>

This example enables host recovery on a Dedicated Host.

#### Sample Request
<a name="API_ModifyHosts_Example_2_Request"></a>

```
https://ec2.amazonaws.com/?Action=ModifyHosts
&HostRecovery=on
&HostId=h-00548908djdsgfs
&AUTHPARAMS
```

#### Sample Response
<a name="API_ModifyHosts_Example_2_Response"></a>

```
<ModifyHostsResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
    <requestId>d4904fd9-82c2-4ea5-adfe-a9cc3EXAMPLE</requestId>
    <unsuccessful/>
    <successful>
        <item>h-00548908djdsgfs</item>
    </successful>
</ModifyHostsResponse>
```

### Example 3
<a name="API_ModifyHosts_Example_3"></a>

This example modifies a Dedicated Host that supports only `m5.large` instances to support multiple instance types in the `m5` instance family.

#### Sample Request
<a name="API_ModifyHosts_Example_3_Request"></a>

```
https://ec2.amazonaws.com/?Action=ModifyHosts
&InstanceFamily=m5
&HostId=h-00548908djdsgfs
&AUTHPARAMS
```

#### Sample Response
<a name="API_ModifyHosts_Example_3_Response"></a>

```
<ModifyHostsResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
    <requestId>d4904fd9-82c2-4ea5-adfe-a9cc3EXAMPLE</requestId>
    <unsuccessful/>
    <successful>
        <item>h-00548908djdsgfs</item>
    </successful>
</ModifyHostsResponse>
```

## See Also
<a name="API_ModifyHosts_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/ec2-2016-11-15/ModifyHosts) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ec2-2016-11-15/ModifyHosts)