cloudformation, error creating a change: set Parameter 'ami' must be one of AllowedValues

    "ami" : {

      "Description": "ami of instance",

      "Type" : "AWS::EC2::Image::Id",

      "AllowedValues" : [

        "ami-00000000","ami-00000000", "ami-00000000"

      ]

    }

Whatever value you are providing as value of the ami parameter needs to be one of AllowedValues. Since all the IDs in the AllowedValues are invalid, it is safe to assume that you aren't providing one of these values. Removing the AllowedValues constraint (or correcting the list) would fix this:

    "ami" : {

      "Description": "ami of instance",

      "Type" : "AWS::EC2::Image::Id"

    }