For in-mesh networking (no ingress or egress in my simple example), it seems like the common practice to have the "host" of a virtual service match an existing kubernetes service:

hosts:
- reviews.default.svc.cluster.local

But is this required? If I wanted to create a virtual service for an entirely different host name, is that possible? For example:

hosts:
- review-service.my-servicemesh

And then call the service at http://review-service.my-servicemesh instead of http://reviews (or http://reviews.default) ?

Or to ask this another way: can I have my namespace of istio (virtual) services be entirely decoupled from the namespace of kubernetes services/namespaces?