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Management Guide

Tag Restrictions

The following basic restrictions apply to tags:

  • The maximum number of tags per resource is 10.

  • The maximum key length is 127 Unicode characters.

  • The maximum value length is 255 Unicode characters.

  • Tag keys and values are case sensitive.

  • Do not use the aws: prefix in tag names and values because it is reserved for AWS use. In addition, you cannot edit or delete tag names or values with this prefix.

  • You cannot change or edit tags on a terminated cluster.

  • A tag value can be an empty string, but not null. In addition, a tag key cannot be an empty string.

  • Keys and values can contain any alphabetic character in any language, any numeric character, white spaces, invisible separators, and the following symbols: _ . : / = + - @

For more information about tagging using the AWS Management Console, see Working with Tags in the Console in the Amazon EC2 User Guide for Linux Instances. For more information about tagging using the Amazon EC2API or command line, see API and CLI Overview in the Amazon EC2 User Guide for Linux Instances.