# StackSetOperationPreferences
<a name="API_StackSetOperationPreferences"></a>

The user-specified preferences for how CloudFormation performs a StackSet operation.

For more information about maximum concurrent accounts and failure tolerance, see [StackSet operation options](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/stacksets-concepts.html#stackset-ops-options).

**Note**  
 `StackSetOperationPreferences` don't apply to `AutoDeployment`, even if it's enabled.

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

 ** ConcurrencyMode **   
Specifies how the concurrency level behaves during the operation execution.  
+  `STRICT_FAILURE_TOLERANCE`: This option dynamically lowers the concurrency level to ensure the number of failed accounts never exceeds the value of `FailureToleranceCount` \$11. The initial actual concurrency is set to the lower of either the value of the `MaxConcurrentCount`, or the value of `FailureToleranceCount` \$11. The actual concurrency is then reduced proportionally by the number of failures. This is the default behavior.

  If failure tolerance or Maximum concurrent accounts are set to percentages, the behavior is similar.
+  `SOFT_FAILURE_TOLERANCE`: This option decouples `FailureToleranceCount` from the actual concurrency. This allows StackSet operations to run at the concurrency level set by the `MaxConcurrentCount` value, or `MaxConcurrentPercentage`, regardless of the number of failures.
Type: String  
Valid Values: `STRICT_FAILURE_TOLERANCE | SOFT_FAILURE_TOLERANCE`   
Required: No

 ** FailureToleranceCount **   
The number of accounts per Region this operation can fail in before CloudFormation stops the operation in that Region. If the operation is stopped in a Region, CloudFormation doesn't attempt the operation in any subsequent Regions.  
You can specify either `FailureToleranceCount` or `FailureTolerancePercentage`, but not both.  
By default, `0` is specified.  
Type: Integer  
Valid Range: Minimum value of 0.  
Required: No

 ** FailureTolerancePercentage **   
The percentage of accounts per Region this stack operation can fail in before CloudFormation stops the operation in that Region. If the operation is stopped in a Region, CloudFormation doesn't attempt the operation in any subsequent Regions.  
When calculating the number of accounts based on the specified percentage, CloudFormation rounds *down* to the next whole number.  
You can specify either `FailureToleranceCount` or `FailureTolerancePercentage`, but not both.  
By default, `0` is specified.  
Type: Integer  
Valid Range: Minimum value of 0. Maximum value of 100.  
Required: No

 ** MaxConcurrentCount **   
The maximum number of accounts in which to perform this operation at one time. This can depend on the value of `FailureToleranceCount` depending on your `ConcurrencyMode`. `MaxConcurrentCount` is at most one more than the `FailureToleranceCount` if you're using `STRICT_FAILURE_TOLERANCE`.  
Note that this setting lets you specify the *maximum* for operations. For large deployments, under certain circumstances the actual number of accounts acted upon concurrently may be lower due to service throttling.  
You can specify either `MaxConcurrentCount` or `MaxConcurrentPercentage`, but not both.  
By default, `1` is specified.  
Type: Integer  
Valid Range: Minimum value of 1.  
Required: No

 ** MaxConcurrentPercentage **   
The maximum percentage of accounts in which to perform this operation at one time.  
When calculating the number of accounts based on the specified percentage, CloudFormation rounds down to the next whole number. This is true except in cases where rounding down would result is zero. In this case, CloudFormation sets the number as one instead.  
Note that this setting lets you specify the *maximum* for operations. For large deployments, under certain circumstances the actual number of accounts acted upon concurrently may be lower due to service throttling.  
You can specify either `MaxConcurrentCount` or `MaxConcurrentPercentage`, but not both.  
By default, `1` is specified.  
Type: Integer  
Valid Range: Minimum value of 1. Maximum value of 100.  
Required: No

 ** RegionConcurrencyType **   
The concurrency type of deploying StackSets operations in Regions, could be in parallel or one Region at a time.  
Type: String  
Valid Values: `SEQUENTIAL | PARALLEL`   
Required: No

 ** RegionOrder.member.N **   
The order of the Regions where you want to perform the stack operation.  
Type: Array of strings  
Pattern: `^[a-zA-Z0-9-]{1,128}$`   
Required: No

## See Also
<a name="API_StackSetOperationPreferences_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/cloudformation-2010-05-15/StackSetOperationPreferences) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/cloudformation-2010-05-15/StackSetOperationPreferences) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/cloudformation-2010-05-15/StackSetOperationPreferences)