Multiple ExGW: fixes unique pod exgw cache key

When pods are added to the cache as exgws for a namespace, only the
pod's name is used as the key. This breaks a scenario where 2 pods with
the same name are serving as exgws for the same namespace. Consider this
example:

1. app pod is created in ns foo
2. exgwAPod is created in ns exgw1 (172.0.1.1), serving ns foo
3. exgwAPod is created in ns exgw2 (172.0.1.2), serving ns foo

In the above example, the app pod will only have one ECMP route for
172.0.1.2, because the cache is keyed only on pod name.

Signed-off-by: Tim Rozet <trozet@redhat.com>

go-controller/pkg/ovn/egressgw.go

@@ -197,7 +197,7 @@ func (oc *Controller) addPodExternalGWForNamespace(namespace string, pod *kapi.P
 			pod.Namespace, pod.Name, namespace, err)
 	}
 
-	nsInfo.routingExternalPodGWs[pod.Name] = egress
+	nsInfo.routingExternalPodGWs[makePodGWKey(pod)] = egress
 	nsUnlock()
 
 	klog.Infof("Adding routes for external gateway pod: %s, next hops: %q, namespace: %s, bfd-enabled: %t",
@@ -351,19 +351,20 @@ func (oc *Controller) deletePodExternalGW(pod *kapi.Pod) {
 	klog.Infof("Deleting routes for external gateway pod: %s, for namespace(s) %s", pod.Name,
 		podRoutingNamespaceAnno)
 	for _, namespace := range strings.Split(podRoutingNamespaceAnno, ",") {
-		oc.deletePodGWRoutesForNamespace(pod.Name, namespace)
+		oc.deletePodGWRoutesForNamespace(pod, namespace)
 	}
 }
 
 // deletePodGwRoutesForNamespace handles deleting all routes in a namespace for a specific pod GW
-func (oc *Controller) deletePodGWRoutesForNamespace(pod, namespace string) {
+func (oc *Controller) deletePodGWRoutesForNamespace(pod *kapi.Pod, namespace string) {
 	nsInfo, nsUnlock := oc.getNamespaceLocked(namespace, false)
 	if nsInfo == nil {
 		return
 	}
+	podGWKey := makePodGWKey(pod)
 	// check if any gateways were stored for this pod
-	foundGws, ok := nsInfo.routingExternalPodGWs[pod]
-	delete(nsInfo.routingExternalPodGWs, pod)
+	foundGws, ok := nsInfo.routingExternalPodGWs[podGWKey]
+	delete(nsInfo.routingExternalPodGWs, podGWKey)
 	nsUnlock()
 
 	if !ok || len(foundGws.gws) == 0 {
@@ -1250,3 +1251,7 @@ func (oc *Controller) buildOVNECMPCache() map[string][]*ovnRoute {
 	}
 	return ovnRouteCache
 }
+
+func makePodGWKey(pod *kapi.Pod) string {
+	return fmt.Sprintf("%s_%s", pod.Namespace, pod.Name)
+}

go-controller/pkg/ovn/ovn.go

@@ -89,6 +89,7 @@ type namespaceInfo struct {
 
 	// routingExternalPodGWs contains a map of all pods serving as exgws as well as their
 	// exgw IPs
+	// key is <namespace>_<pod name>
 	routingExternalPodGWs map[string]gatewayInfo
 
 	multicastEnabled bool