Tagging limitations - Amazon EMR
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Tagging limitations

The following basic limitations apply to tags:

  • Each resource can have a maximum of 50 user-created tags.

  • For each resource, each tag key must be unique, and each tag key can have only one value.

  • The maximum key length is 128 Unicode characters in UTF-8.

  • The maximum value length is 256 Unicode characters in UTF-8.

  • Allowed characters are letters, numbers, spaces representable in UTF-8, and the following characters: _ . : / = + - @.

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

  • Tag keys and values are case sensitive.

  • Do not use Amazon: or any upper or lowercase combination of such as a prefix for either keys or values. These are reserved only for Amazon use.