From 4147ad7db6dc5532af7d26a6f6acbf27bc59fb85 Mon Sep 17 00:00:00 2001
From: veophi <sunweixiang@xiaohongshu.com>
Date: Wed, 11 Sep 2024 17:03:26 +0800
Subject: [PATCH] a feature-gate to limit cloneset pod name within 63 chars or
 less

Signed-off-by: veophi <sunweixiang@xiaohongshu.com>
---
 pkg/controller/cloneset/core/cloneset_core.go | 18 ++++++-
 .../cloneset/core/cloneset_core_test.go       | 47 +++++++++++++++++++
 pkg/features/kruise_features.go               |  4 ++
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/pkg/controller/cloneset/core/cloneset_core.go b/pkg/controller/cloneset/core/cloneset_core.go
index 5c26b22861..237dc9108b 100644
--- a/pkg/controller/cloneset/core/cloneset_core.go
+++ b/pkg/controller/cloneset/core/cloneset_core.go
@@ -27,14 +27,21 @@ import (
 	"k8s.io/klog/v2"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
 	kubecontroller "k8s.io/kubernetes/pkg/controller"
+	"k8s.io/utils/integer"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 
 	appspub "github.com/openkruise/kruise/apis/apps/pub"
 	appsv1alpha1 "github.com/openkruise/kruise/apis/apps/v1alpha1"
 	clonesetutils "github.com/openkruise/kruise/pkg/controller/cloneset/utils"
+	"github.com/openkruise/kruise/pkg/features"
+	utilfeature "github.com/openkruise/kruise/pkg/util/feature"
 	"github.com/openkruise/kruise/pkg/util/inplaceupdate"
 )
 
+const (
+	shortNameLimitation = 63
+)
+
 var (
 	inPlaceUpdateTemplateSpecPatchRexp = regexp.MustCompile("^/containers/([0-9]+)/image$")
 )
@@ -96,7 +103,7 @@ func (c *commonControl) newVersionedPods(cs *appsv1alpha1.CloneSet, revision str
 		}
 		clonesetutils.WriteRevisionHash(pod, revision)
 
-		pod.Name = fmt.Sprintf("%s-%s", cs.Name, id)
+		pod.Name = generatePodName(cs.Name, id)
 		pod.Namespace = cs.Namespace
 		pod.Labels[appsv1alpha1.CloneSetInstanceID] = id
 
@@ -249,3 +256,12 @@ func lifecycleFinalizerChanged(cs *appsv1alpha1.CloneSet, oldPod, curPod *v1.Pod
 
 	return false
 }
+
+func generatePodName(prefix, id string) string {
+	name := fmt.Sprintf("%s-%s", prefix, id)
+	if !utilfeature.DefaultFeatureGate.Enabled(features.CloneSetShortPodName) || len(name) < shortNameLimitation {
+		return name
+	}
+	maxPrefixLen := integer.IntMax(integer.IntMin(len(prefix), 63-len(id)), 0)
+	return fmt.Sprintf("%s%s", prefix[:maxPrefixLen], id)
+}
diff --git a/pkg/controller/cloneset/core/cloneset_core_test.go b/pkg/controller/cloneset/core/cloneset_core_test.go
index 75da20c915..faf66a1de8 100644
--- a/pkg/controller/cloneset/core/cloneset_core_test.go
+++ b/pkg/controller/cloneset/core/cloneset_core_test.go
@@ -5,6 +5,8 @@ import (
 	"testing"
 
 	appsv1alpha1 "github.com/openkruise/kruise/apis/apps/v1alpha1"
+	"github.com/openkruise/kruise/pkg/features"
+	utilfeature "github.com/openkruise/kruise/pkg/util/feature"
 	"github.com/openkruise/kruise/pkg/util/inplaceupdate"
 )
 
@@ -72,3 +74,48 @@ func Test_CommonControl_GetUpdateOptions(t *testing.T) {
 		})
 	}
 }
+
+func TestGeneratePodName(t *testing.T) {
+	tests := []struct {
+		name      string
+		prefix    string
+		id        string
+		shortName string
+		longName  string
+	}{
+		{
+			name:      "short prefix case",
+			prefix:    "short-prefix",
+			id:        "abcdefg",
+			shortName: "short-prefix-abcdefg",
+			longName:  "short-prefix-abcdefg",
+		},
+		{
+			name:      "long prefix case",
+			prefix:    "looooooooooooooooooooooooooooooooooooooooooooooooooooooooong-prefix",
+			id:        "abcdefg",
+			shortName: "loooooooooooooooooooooooooooooooooooooooooooooooooooooooabcdefg",
+			longName:  "looooooooooooooooooooooooooooooooooooooooooooooooooooooooong-prefix-abcdefg",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			defer utilfeature.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.CloneSetShortPodName, true)()
+			generatedName := generatePodName(test.prefix, test.id)
+			if generatedName != test.shortName || len(generatedName) > 63 {
+				t.Fatalf("expect %s, but got %s", test.shortName, generatedName)
+			}
+		})
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			defer utilfeature.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.CloneSetShortPodName, false)()
+			generatedName := generatePodName(test.prefix, test.id)
+			if generatedName != test.longName {
+				t.Fatalf("expect %s, but got %s", test.longName, generatedName)
+			}
+		})
+	}
+}
diff --git a/pkg/features/kruise_features.go b/pkg/features/kruise_features.go
index 78eab56276..0600c14dae 100644
--- a/pkg/features/kruise_features.go
+++ b/pkg/features/kruise_features.go
@@ -131,6 +131,9 @@ const (
 
 	// Enables policies auto resizing PVCs created by a StatefulSet when user expands volumeClaimTemplates.
 	StatefulSetAutoResizePVCGate featuregate.Feature = "StatefulSetAutoResizePVCGate"
+
+	// CloneSetShortPodName enable CloneSet create Pods with 63 name length or less.
+	CloneSetShortPodName featuregate.Feature = "CloneSetShortPodName"
 )
 
 var defaultFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
@@ -166,6 +169,7 @@ var defaultFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
 	PodIndexLabel:                          {Default: true, PreRelease: featuregate.Beta},
 	EnableExternalCerts:                    {Default: false, PreRelease: featuregate.Alpha},
 	StatefulSetAutoResizePVCGate:           {Default: false, PreRelease: featuregate.Alpha},
+	CloneSetShortPodName:                   {Default: false, PreRelease: featuregate.Alpha},
 }
 
 func init() {