Naming requirements - Amazon CloudTrail
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Naming requirements

This section provides information about the naming requirements for CloudTrail resources, Amazon S3 buckets, and KMS keys.

CloudTrail resource naming requirements

CloudTrail resource names must meet the following requirements:

  • Contain only ASCII letters (a-z, A-Z), numbers (0-9), periods (.), underscores (_), or dashes (-).

  • Start with a letter or number, and end with a letter or number.

  • Be between 3 and 128 characters.

  • Have no adjacent periods, underscores or dashes. Names like my-_namespace and my-\-namespace are invalid.

  • Not be in IP address format (for example,

Amazon S3 bucket naming requirements

The Amazon S3 bucket that you use to store CloudTrail log files must have a name that conforms with naming requirements for non-US Standard regions. Amazon S3 defines a bucket name as a series of one or more labels, separated by periods. For a complete list of naming rules, see Bucket naming rules in the Amazon Simple Storage Service User Guide.

The following are some of the rules:

  • The bucket name can be between 3 and 63 characters long, and can contain only lower-case characters, numbers, periods, and dashes.

  • Each label in the bucket name must start with a lowercase letter or number.

  • The bucket name cannot contain underscores, end with a dash, have consecutive periods, or use dashes adjacent to periods.

  • The bucket name cannot be formatted as an IP address (


Because S3 allows your bucket to be used as a URL that can be accessed publicly, the bucket name that you choose must be globally unique. If some other account has already created a bucket with the name that you chose, you must use another name. For more information, see Bucket restrictions and limitations in the Amazon Simple Storage Service User Guide.

Amazon KMS alias naming requirements

When you create an Amazon KMS key, you can choose an alias to identify it. For example, you might choose the alias "KMS-CloudTrail-us-west-2" to encrypt the logs for a specific trail.

The alias must meet the following requirements:

  • Between 1 and 256 characters, inclusive

  • Contain alphanumeric characters (A-Z, a-z, 0-9), hyphens (-), forward slashes (/), and underscores (_)

  • Cannot begin with aws

For more information, see Creating Keys in the Amazon Key Management Service Developer Guide.