Bug-2088346: ovn-k needs 2 default gateways for dual-stack

Fixes: Bug-2088346

Author: mkowalski

modules/installation-configuration-parameters.adoc

@@ -300,6 +300,8 @@ If you configure your cluster to use both IP address families, review the follow
 
 * Both IP families must use the same network interface for the default gateway.
 
+* Both IP families must have the default gateway.
+
 * You must specify IPv4 and IPv6 addresses in the same order for all network configuration parameters. For example, in the following configuration IPv4 addresses are listed before IPv6 addresses.
 +
 [source,yaml]

modules/nw-ovn-kuberentes-limitations.adoc

@@ -12,7 +12,7 @@ The OVN-Kubernetes Container Network Interface (CNI) cluster network provider ha
 // The foll limitation is also recorded in the installation section.
 * For clusters 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 like `oc get pod -n openshift-ovn-kubernetes -l app=ovnkube-node -o yaml`, the `status` field contains more than one message about the default gateway, as shown in the following output:
+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 contains more than one message about the default gateway, as shown in the following output:
 +
 [source,terminal]
 ----
@@ -22,3 +22,15 @@ F1006 16:09:50.985939   60651 ovnkube.go:130] multiple gateway interfaces detect
 ----
 +
 The only resolution is to reconfigure the host networking so that both IP families use the same network interface for the default gateway.
+
+* For clusters 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 contains more than one message about the default gateway, as shown in the following output:
++
+[source,terminal]
+----
+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.