Docker Swarm does not have anything like Kubernetes Namespaces. We cannot split a Swarm cluster into sections. Therefore, we can finish this comparison by saying that Kubernetes is a clear winner regarding this feature since Docker Swarm doesn't have Namespaces. But, that would not be entirely accurate.
Docker Swarm stacks are, in a way, similar to Kubernetes Namespaces. All the services in a stack are uniquely identified through a combination of a stack name and the names of services inside it. By default, all services within a stack can communicate with each other through the stack's default network. Services can speak with those from other stacks only if they are explicitly attached to the same network. All in all, each Swarm stack is separated from other stacks. They are, in a way, similar...