# PlacementType
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The Amazon EC2 Availability Zone configuration of the cluster (job flow).

## Contents
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 ** AvailabilityZone **   <a name="EMR-Type-PlacementType-AvailabilityZone"></a>
The Amazon EC2 Availability Zone for the cluster. `AvailabilityZone` is used for uniform instance groups, while `AvailabilityZones` (plural) is used for instance fleets.  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 10280.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: No

 ** AvailabilityZones **   <a name="EMR-Type-PlacementType-AvailabilityZones"></a>
When multiple Availability Zones are specified, Amazon EMR evaluates them and launches instances in the optimal Availability Zone. `AvailabilityZones` is used for instance fleets, while `AvailabilityZone` (singular) is used for uniform instance groups.  
The instance fleet configuration is available only in Amazon EMR releases 4.8.0 and later, excluding 5.0.x versions.
Type: Array of strings  
Length Constraints: Minimum length of 0. Maximum length of 256.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: No

## See Also
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For more information about using this API in one of the language-specific Amazon SDKs, see the following:
+  [Amazon SDK for C\$1\$1](https://docs.amazonaws.cn/goto/SdkForCpp/elasticmapreduce-2009-03-31/PlacementType) 
+  [Amazon SDK for Java V2](https://docs.amazonaws.cn/goto/SdkForJavaV2/elasticmapreduce-2009-03-31/PlacementType) 
+  [Amazon SDK for Ruby V3](https://docs.amazonaws.cn/goto/SdkForRubyV3/elasticmapreduce-2009-03-31/PlacementType)