Running Couchbase Sync Gateway instances in Kubernetes

Following documentation lists that Couchbase server running in Kubernetes is a prerequisite for deploying Couchbase Sync Gateway in Kubernetes.
https://docs.couchbase.com/sync-gateway/2.6/kubernetes/deploy-cluster.html

Is that a hard requirement? As sync gateway is stateless is it possible to run them in containers but run couchbase server instances on dedicated hardware. Is that configuration recommend ? if not why?