A parameter label is a user-defined alias to help you manage different versions of a parameter. When you modify a parameter, Systems Manager automatically saves a new version and increments the version number by one. A label can help you remember the purpose of a parameter when there are multiple versions.
Parameter labels have the following requirements and restrictions.
- A version of a parameter can have a maximum of 10 labels.
- You can't attach the same label to different versions of the same parameter. For example, if version 1 has the label Production, then you can't attach Production to version 2.
- You can move a label from one version of a parameter to another.
- You can't create a label when you create a new parameter. You must attach a label to a specific version of a parameter.
- You can't delete a parameter label. If you no longer want to use a parameter label, then you must move it to a different version of a parameter.
- A label can have a maximum of 100 characters.
- Labels can contain letters (case sensitive), numbers, periods (.), hyphens (-), or underscores (_).
- Labels can't begin with a number, "aws," or "ssm" (not case sensitive). If a label fails to meet these requirements, then the label is not associated with a parameter and the system displays it in the list of InvalidLabels.