4.6. OVN-Kubernetes IPv6 and dual-stack limitations

For a cluster configured for dual-stack networking, both IPv4 and IPv6 traffic must use the same network interface as the default gateway.

If this requirement is not met, pods on the host in the ovnkube-node daemon set enter the CrashLoopBackOff state.

If you display a pod with a command such as oc get pod -n openshift-ovn-kubernetes -l app=ovnkube-node -o yaml, the status field has more than one message about the default gateway, as shown in the following output:

I1006 16:09:50.985852   60651 helper_linux.go:73] Found default gateway interface br-ex 192.168.127.1
I1006 16:09:50.985923   60651 helper_linux.go:73] Found default gateway interface ens4 fe80::5054:ff:febe:bcd4
F1006 16:09:50.985939   60651 ovnkube.go:130] multiple gateway interfaces detected: br-ex ens4

The only resolution is to reconfigure the host networking so that both IP families use the same network interface for the default gateway.

For a cluster configured for dual-stack networking, both the IPv4 and IPv6 routing tables must contain the default gateway.

If this requirement is not met, pods on the host in the ovnkube-node daemon set enter the CrashLoopBackOff state.

If you display a pod with a command such as oc get pod -n openshift-ovn-kubernetes -l app=ovnkube-node -o yaml, the status field has more than one message about the default gateway, as shown in the following output:

I0512 19:07:17.589083  108432 helper_linux.go:74] Found default gateway interface br-ex 192.168.123.1
F0512 19:07:17.589141  108432 ovnkube.go:133] failed to get default gateway interface

The only resolution is to reconfigure the host networking so that both IP families contain the default gateway.