Don't recreate clusterPGs and clusterRtrPGs unless needed

In SetupMaster, we always call CreateOrUpdatePortGroupsOps
with empty ACLs and PGs for the cluster-wide port group
and cluster-wide-router-PG. This is disruptive during
upgrades since momentarily all efw ACLs and multicast ACLs
will be wiped out.

This commit changes this to first check if the PG already exists,
if then no need to do anything.
Each of those features are responsible for ensuring ACLs, Ports
are good on those PGs they own.

NOTE: This bug was an issue for multicast and started being an
issue for egf from ovn-org@bd29f41
Before that we didn't have ACLs on cluster wide PG.

Signed-off-by: Surya Seetharaman <suryaseetharaman.9@gmail.com>
(cherry picked from commit 935bc55)

go-controller/pkg/ovn/master.go

@@ -14,6 +14,7 @@ import (
 	"k8s.io/klog/v2"
 	utilnet "k8s.io/utils/net"
 
+	libovsdbclient "github.com/ovn-org/libovsdb/client"
 	"github.com/ovn-org/ovn-kubernetes/go-controller/pkg/config"
 	"github.com/ovn-org/ovn-kubernetes/go-controller/pkg/kube"
 	"github.com/ovn-org/ovn-kubernetes/go-controller/pkg/libovsdbops"
@@ -118,23 +119,43 @@ func (oc *DefaultNetworkController) SetupMaster(existingNodeNames []string) erro
 	}
 	oc.defaultCOPPUUID = *(logicalRouter.Copp)
 
-	// Create a cluster-wide port group that all logical switch ports are part of
-	pg := libovsdbops.BuildPortGroup(types.ClusterPortGroupName, types.ClusterPortGroupName, nil, nil)
-	err = libovsdbops.CreateOrUpdatePortGroups(oc.nbClient, pg)
-	if err != nil {
-		klog.Errorf("Failed to create cluster port group: %v", err)
+	pg := &nbdb.PortGroup{
+		Name: types.ClusterPortGroupName,
+	}
+	pg, err = libovsdbops.GetPortGroup(oc.nbClient, pg)
+	if err != nil && err != libovsdbclient.ErrNotFound {
 		return err
 	}
+	if pg == nil {
+		// we didn't find an existing clusterPG, let's create a new empty PG (fresh cluster install)
+		// Create a cluster-wide port group that all logical switch ports are part of
+		pg := libovsdbops.BuildPortGroup(types.ClusterPortGroupName, types.ClusterPortGroupName, nil, nil)
+		err = libovsdbops.CreateOrUpdatePortGroups(oc.nbClient, pg)
+		if err != nil {
+			klog.Errorf("Failed to create cluster port group: %v", err)
+			return err
+		}
+	}
 
-	// Create a cluster-wide port group with all node-to-cluster router
-	// logical switch ports.  Currently the only user is multicast but it might
-	// be used for other features in the future.
-	pg = libovsdbops.BuildPortGroup(types.ClusterRtrPortGroupName, types.ClusterRtrPortGroupName, nil, nil)
-	err = libovsdbops.CreateOrUpdatePortGroups(oc.nbClient, pg)
-	if err != nil {
-		klog.Errorf("Failed to create cluster port group: %v", err)
+	pg = &nbdb.PortGroup{
+		Name: types.ClusterRtrPortGroupName,
+	}
+	pg, err = libovsdbops.GetPortGroup(oc.nbClient, pg)
+	if err != nil && err != libovsdbclient.ErrNotFound {
 		return err
 	}
+	if pg == nil {
+		// we didn't find an existing clusterRtrPG, let's create a new empty PG (fresh cluster install)
+		// Create a cluster-wide port group with all node-to-cluster router
+		// logical switch ports. Currently the only user is multicast but it might
+		// be used for other features in the future.
+		pg = libovsdbops.BuildPortGroup(types.ClusterRtrPortGroupName, types.ClusterRtrPortGroupName, nil, nil)
+		err = libovsdbops.CreateOrUpdatePortGroups(oc.nbClient, pg)
+		if err != nil {
+			klog.Errorf("Failed to create cluster port group: %v", err)
+			return err
+		}
+	}
 
 	// If supported, enable IGMP relay on the router to forward multicast
 	// traffic between nodes.