Networking Model

The OpenShift SDN uses Linux namespaces to partition the usage of resources and processes on physical and virtual hosts. This implementation allows containers inside pods to share network resources, such as devices, IP stacks, firewall rules, and also routing tables.

The OpenShift SDN allocates a unique routable IP to each pod so that you can access the pod from any other service in the same network.

The SDN design makes it easy to containerize your legacy applications because you do not need to change the way the application components communicate with each other.

If your application is comprised of many services that communicate over the TCP/UDP stack, this approach still works as containers in a pod share the same network stack. Although using OKD services is the recommended approach, you can seamlessly migrate those services before considering migrating all your services in OKD.

The following diagram shows how all pods are connected to a shared network.