# InstanceRefresh
<a name="API_InstanceRefresh"></a>

Describes an instance refresh for an Auto Scaling group. 

## Contents
<a name="API_InstanceRefresh_Contents"></a>

 ** AutoScalingGroupName **   
The name of the Auto Scaling group.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 255.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: No

 ** DesiredConfiguration **   
Describes the desired configuration for the instance refresh.  
Type: [DesiredConfiguration](API_DesiredConfiguration.md) object  
Required: No

 ** EndTime **   
The date and time at which the instance refresh ended.  
Type: Timestamp  
Required: No

 ** InstanceRefreshId **   
The instance refresh ID.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 255.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: No

 ** InstancesToUpdate **   
The number of instances remaining to update before the instance refresh is complete.  
If you roll back the instance refresh, `InstancesToUpdate` shows you the number of instances that were not yet updated by the instance refresh. Therefore, these instances don't need to be replaced as part of the rollback.
Type: Integer  
Valid Range: Minimum value of 0.  
Required: No

 ** PercentageComplete **   
The percentage of the instance refresh that is complete. For each instance replacement, Amazon EC2 Auto Scaling tracks the instance's health status and warm-up time. When the instance's health status changes to healthy and the specified warm-up time passes, the instance is considered updated and is added to the percentage complete.  
 `PercentageComplete` does not include instances that are replaced during a rollback. This value gradually goes back down to zero during a rollback.
Type: Integer  
Valid Range: Minimum value of 0. Maximum value of 100.  
Required: No

 ** Preferences **   
The preferences for an instance refresh.  
Type: [RefreshPreferences](API_RefreshPreferences.md) object  
Required: No

 ** ProgressDetails **   
Additional progress details for an Auto Scaling group that has a warm pool.  
Type: [InstanceRefreshProgressDetails](API_InstanceRefreshProgressDetails.md) object  
Required: No

 ** RollbackDetails **   
The rollback details.  
Type: [RollbackDetails](API_RollbackDetails.md) object  
Required: No

 ** StartTime **   
The date and time at which the instance refresh began.  
Type: Timestamp  
Required: No

 ** Status **   
The current status for the instance refresh operation:  
+  `Pending` - The request was created, but the instance refresh has not started.
+  `InProgress` - An instance refresh is in progress.
+  `Successful` - An instance refresh completed successfully.
+  `Failed` - An instance refresh failed to complete. You can troubleshoot using the status reason and the scaling activities. 
+  `Cancelling` - An ongoing instance refresh is being cancelled.
+  `Cancelled` - The instance refresh is cancelled. 
+  `RollbackInProgress` - An instance refresh is being rolled back.
+  `RollbackFailed` - The rollback failed to complete. You can troubleshoot using the status reason and the scaling activities.
+  `RollbackSuccessful` - The rollback completed successfully.
+  `Baking` - Waiting the specified bake time after an instance refresh has finished updating instances.
Type: String  
Valid Values: `Pending | InProgress | Successful | Failed | Cancelling | Cancelled | RollbackInProgress | RollbackFailed | RollbackSuccessful | Baking`   
Required: No

 ** StatusReason **   
The explanation for the specific status assigned to this operation.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 1023.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: No

 ** Strategy **   
 The strategy to use for the instance refresh. This determines how instances in the Auto Scaling group are updated. Default is Rolling.   
+  `Rolling` – Terminates instances and launches replacements in batches
+  `ReplaceRootVolume` – Updates instances by replacing only the root volume without terminating the instance
Type: String  
Valid Values: `Rolling | ReplaceRootVolume`   
Required: No

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

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/autoscaling-2011-01-01/InstanceRefresh) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/autoscaling-2011-01-01/InstanceRefresh) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/autoscaling-2011-01-01/InstanceRefresh)