Network Modes

The OpenShift software-defined networking (SDN) provides the network layer that the pods in the cluster use for communication. To establish this network layer, the OpenShift SDN uses a plugin model that allows you to select the appropriate technology for your use case.

In OKD, the OpenShifSDN API resource defines and manages the SDN mode. Configure the mode to use in the defaultNetwork section of the installconfig.yaml installation file.

OKD supports three modes: Multitenant, Subnet, and NetworkPolicy; the default mode is NetworkPolicy. The following excerpt shows the SDN mode configuration:

    type: OpenShiftSDN
        mode: NetworkPolicy
        mtu: 1450
        vxlanPort: 4789

The configuration instructs the installer to use the NetworkPolicy mode, and to define the values of the MTU overlay and the VXLAN UDP port for creating the tunnel.

Adjust the MTU value to prevent packets fragmentation, which typically happens when you encapsulate an Ethernet frame into another frame, such as for overlay networks.