serviceLabel

An optional prefix to the service name for this Forwarding Rule. If specified, will be the first label of the fully qualified service name. The label must be 1-63 characters long, and comply with RFC1035. Specifically, the label must be 1-63 characters long and match the regular expression a-z? which means the first character must be a lowercase letter, and all following characters must be a dash, lowercase letter, or digit, except the last character, which cannot be a dash. This field is only used for INTERNAL load balancing.