OVN-Kubernetes (OVN-K) is the default CNI plugin in OpenShift. It uses Open vSwitch (OVS) internally and attaches the node's primary NIC to a bridge named br-ex. The node IP then sits on br-ex, not directly on the physical NIC (e.g. eno2). That is why ip addr show eno2 may show no IP, while ip addr show br-ex does.
✓ ADVANTAGES
- Fully integrated software-defined networking for the whole cluster
- Supports NetworkPolicies, multi-tenancy, and service routing natively
⚠ LIMITATIONS
- The physical NIC is blocked for other uses (e.g. a second Linux bridge)
- Changes to br-ex are risky because OVN-K manages and may overwrite them
📍 WHY IT MATTERS HERE
Explains why eno2 cannot be used directly for VM bridges on this Hetzner SNO (PRE-02/03), and why OVN-K localnet is the officially supported path for physical LAN access instead (TC-NET-002).