core: do not watch resourceversion and heartbeat node updates

currently node predicate watches for resourceversion and
heartbeat, which are not critical things so we should
look for the reconcile logic and unnecessary
increasing the predicate cache size,
So with the PR we will ignore conidering for a reconcile
of cephcluster if updates are not cruical

closes: #14070

Signed-off-by: parth-gr <paarora@redhat.com>

pkg/operator/ceph/cluster/predicate.go

@@ -21,19 +21,36 @@ import (
 	"context"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	cephv1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1"
 	"github.com/rook/rook/pkg/clusterd"
 	discoverDaemon "github.com/rook/rook/pkg/daemon/discover"
 	"github.com/rook/rook/pkg/operator/ceph/controller"
 	"github.com/rook/rook/pkg/operator/k8sutil"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 )
 
+func compareNodes(objOld, objNew *corev1.Node) string {
+	// do not watch node if only resourceversion got changed
+	resourceQtyComparer := cmpopts.IgnoreFields(v1.ObjectMeta{}, "ResourceVersion")
+	diff := cmp.Diff(objOld.Spec, objNew.Spec, resourceQtyComparer)
+
+	// do not watch node if only LastHeartbeatTime got changed
+	resourceQtyComparer = cmpopts.IgnoreFields(corev1.NodeCondition{}, "LastHeartbeatTime")
+	diff1 := cmp.Diff(objOld.Spec, objNew.Spec, resourceQtyComparer)
+
+	if diff == "" && diff1 == "" {
+		return diff
+	}
+	return "not-equal"
+}
+
 // predicateForNodeWatcher is the predicate function to trigger reconcile on Node events
 func predicateForNodeWatcher(ctx context.Context, client client.Client, context *clusterd.Context) predicate.Funcs {
 	return predicate.Funcs{
@@ -43,6 +60,13 @@ func predicateForNodeWatcher(ctx context.Context, client client.Client, context
 		},
 
 		UpdateFunc: func(e event.UpdateEvent) bool {
+			objOld := e.ObjectOld.(*corev1.Node)
+			objNew := e.ObjectNew.(*corev1.Node)
+			diff := compareNodes(objOld, objNew)
+			if diff == "" {
+				return false
+			}
+
 			clientCluster := newClientCluster(client, e.ObjectNew.GetNamespace(), context)
 			return clientCluster.onK8sNode(ctx, e.ObjectNew)
 		},

pkg/operator/ceph/cluster/predicate_test.go

@@ -18,10 +18,12 @@ package cluster
 
 import (
 	"testing"
+	"time"
 
 	cephv1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1"
 	"github.com/stretchr/testify/assert"
 	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 func TestIsHotPlugCM(t *testing.T) {
@@ -40,3 +42,38 @@ func TestIsHotPlugCM(t *testing.T) {
 	cm.Labels["app"] = "rook-discover"
 	assert.True(t, isHotPlugCM(cm))
 }
+
+func TestCompareNodes(t *testing.T) {
+	oldobj := corev1.Node{}
+	newobj := corev1.Node{}
+
+	result := compareNodes(&oldobj, &newobj)
+	assert.Equal(t, result, "")
+
+	oldobj.ResourceVersion = "123"
+	newobj.ResourceVersion = "145"
+	result = compareNodes(&oldobj, &newobj)
+	assert.Equal(t, result, "")
+
+	oldobj.Status = corev1.NodeStatus{
+		Conditions: []corev1.NodeCondition{
+			{
+				LastHeartbeatTime: metav1.NewTime(time.Now()),
+			},
+		},
+	}
+	newobj.Status = corev1.NodeStatus{
+		Conditions: []corev1.NodeCondition{
+			{
+				LastHeartbeatTime: metav1.NewTime(<-time.After(5)),
+			},
+		},
+	}
+	result = compareNodes(&oldobj, &newobj)
+	assert.Equal(t, result, "")
+
+	oldobj.Spec.PodCIDR = "123"
+	newobj.Spec.PodCIDR = "145"
+	result = compareNodes(&oldobj, &newobj)
+	assert.Equal(t, result, "not-equal")
+}