Create Fleet using UGS CLI

Getting Bad Request error while trying to create fleet via UGS CLI
ugs gsh fleet create --name "testf" --os-family LINUX --region-id 85737028-4821-11ea-bcbc-ec0d9af2b8e1 --build-configuration-id "configid" -p "projectid" -e "env"

Error calling CreateFleet: {“title”:“Bad Request”,“detail”:“graceful stop is only supported on reservations-based fleets”,“status”:400,“request_id”:“99d888f3-ff6c-4390-bca3-******”}