<p>If one is running Docker Enterprise with Kubernetes in an on-premises private cloud, is it possible to add clusters in a public cloud like Azure?</p>

<p>On GCP, Anthos is a candidate.<br />
You may have a look on their <a href="https://cloud.google.com/anthos/docs/concepts/overview" rel="nofollow noreferrer">architecture</a> and see if it fits your needs.<br />
Anthos is advertised in most of the GCP architecture courses and offers integration between GKE and both on-prem(the on-prem cluster must meet some prerequisites or you can use the version provided by Google) and AWS Kubernetes clusters.</p>
<p>Istio is a service mesh and if I understood correctly your requirements, <a href="https://istio.io/latest/docs/ops/deployment/deployment-models/#multiple-clusters" rel="nofollow noreferrer">the multiple clusters</a> and <a href="https://istio.io/latest/docs/ops/deployment/deployment-models/#multiple-networks" rel="nofollow noreferrer">multiple networks</a> models could be used.</p>
