Network topology
OVN-Kubernetes provides an overlay-based networking implementation. This overlay includes an OVS-based implementation of Service and NetworkPolicy resources.
The overlay network uses the Geneve (Generic Network Virtualization Encapsulation) tunnel protocol. The pod maximum transmission unit (MTU) for the Geneve tunnel is set to the default route MTU if it is not configured.
To configure the MTU, you must set an equal-to or less-than value than the MTU of the physical interface on the host. A less-than value for the MTU makes room for the required information that is added to the tunnel header before it is transmitted.
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The MTU value of the OVN overlay networking in MicroShift must be 100 bytes smaller than the MTU value of the base network. If no MTU value is configured, MicroShift autoconfigures the value using the MTU value of the default gateway (Internet Protocol version 4 (IPv4) or Internet Protocol version 6 (IPv6)) of the host. If the auto-configuration does not work correctly, the MTU value can be configured manually. For example, if the MTU value of the network is |
OVS runs as a systemd service on the MicroShift node. The OVS RPM package is installed as a dependency to the microshift-networking RPM package. OVS starts immediately when the microshift-networking RPM is installed.