From 3a1dd4f900b040e064e2a2e0562f8270905f0f49 Mon Sep 17 00:00:00 2001
From: aorcholski <84514340+aorcholski@users.noreply.github.com>
Date: Mon, 2 Dec 2024 14:31:39 +0100
Subject: [PATCH] Recreate EEC statefulset for PVC changes only (#4131)

---
 .../dynakube/extension/eec/reconciler_test.go |  4 ++--
 pkg/util/kubeobjects/statefulset/builder.go   | 20 +++++++++++++++++++
 pkg/util/kubeobjects/statefulset/query.go     |  7 ++++---
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/pkg/controllers/dynakube/extension/eec/reconciler_test.go b/pkg/controllers/dynakube/extension/eec/reconciler_test.go
index 90c16302e0..d527949b22 100644
--- a/pkg/controllers/dynakube/extension/eec/reconciler_test.go
+++ b/pkg/controllers/dynakube/extension/eec/reconciler_test.go
@@ -545,7 +545,7 @@ func TestAnnotations(t *testing.T) {
 	t.Run("the default annotations", func(t *testing.T) {
 		statefulSet := getStatefulset(t, getTestDynakube())
 
-		assert.Len(t, statefulSet.ObjectMeta.Annotations, 1)
+		assert.Len(t, statefulSet.ObjectMeta.Annotations, 2)
 		require.Len(t, statefulSet.Spec.Template.ObjectMeta.Annotations, 1)
 		assert.NotEmpty(t, statefulSet.Spec.Template.ObjectMeta.Annotations[consts.ExtensionsAnnotationSecretHash])
 	})
@@ -559,7 +559,7 @@ func TestAnnotations(t *testing.T) {
 
 		statefulSet := getStatefulset(t, dk)
 
-		assert.Len(t, statefulSet.ObjectMeta.Annotations, 1)
+		assert.Len(t, statefulSet.ObjectMeta.Annotations, 2)
 		assert.Empty(t, statefulSet.ObjectMeta.Annotations["a"])
 		require.Len(t, statefulSet.Spec.Template.ObjectMeta.Annotations, 2)
 		assert.Equal(t, "b", statefulSet.Spec.Template.ObjectMeta.Annotations["a"])
diff --git a/pkg/util/kubeobjects/statefulset/builder.go b/pkg/util/kubeobjects/statefulset/builder.go
index 9356a64687..1665926cbe 100644
--- a/pkg/util/kubeobjects/statefulset/builder.go
+++ b/pkg/util/kubeobjects/statefulset/builder.go
@@ -1,6 +1,8 @@
 package statefulset
 
 import (
+	"github.com/Dynatrace/dynatrace-operator/pkg/api"
+	"github.com/Dynatrace/dynatrace-operator/pkg/util/hasher"
 	"github.com/Dynatrace/dynatrace-operator/pkg/util/kubeobjects/internal/builder"
 	maputils "github.com/Dynatrace/dynatrace-operator/pkg/util/map"
 	appsv1 "k8s.io/api/apps/v1"
@@ -9,6 +11,10 @@ import (
 	"k8s.io/utils/ptr"
 )
 
+const (
+	pvcAnnotationHash = api.InternalFlagPrefix + "pvc-hash"
+)
+
 var (
 	// Mandatory fields, provided in constructor as named params
 	setName      = builder.SetName[*appsv1.StatefulSet]
@@ -26,6 +32,8 @@ func Build(owner metav1.Object, name string, container corev1.Container, options
 	}
 	neededOpts = append(neededOpts, options...)
 
+	neededOpts = append(neededOpts, setPVCAnnotation())
+
 	return builder.Build(owner, &appsv1.StatefulSet{}, neededOpts...)
 }
 
@@ -111,3 +119,15 @@ func SetUpdateStrategy(updateStartegy appsv1.StatefulSetUpdateStrategy) builder.
 		s.Spec.UpdateStrategy = updateStartegy
 	}
 }
+
+func setPVCAnnotation() builder.Option[*appsv1.StatefulSet] {
+	return func(s *appsv1.StatefulSet) {
+		if s.Spec.VolumeClaimTemplates != nil {
+			if s.ObjectMeta.Annotations == nil {
+				s.ObjectMeta.Annotations = map[string]string{}
+			}
+
+			s.ObjectMeta.Annotations[pvcAnnotationHash], _ = hasher.GenerateHash(s.Spec.VolumeClaimTemplates)
+		}
+	}
+}
diff --git a/pkg/util/kubeobjects/statefulset/query.go b/pkg/util/kubeobjects/statefulset/query.go
index 65568feff7..39a841f4d8 100644
--- a/pkg/util/kubeobjects/statefulset/query.go
+++ b/pkg/util/kubeobjects/statefulset/query.go
@@ -1,8 +1,6 @@
 package statefulset
 
 import (
-	"reflect"
-
 	"github.com/Dynatrace/dynatrace-operator/pkg/logd"
 	"github.com/Dynatrace/dynatrace-operator/pkg/util/hasher"
 	"github.com/Dynatrace/dynatrace-operator/pkg/util/kubeobjects/internal/query"
@@ -37,5 +35,8 @@ func isEqual(current, desired *appsv1.StatefulSet) bool {
 }
 
 func mustRecreate(current, desired *appsv1.StatefulSet) bool {
-	return labels.NotEqual(current.Spec.Selector.MatchLabels, desired.Spec.Selector.MatchLabels) || !reflect.DeepEqual(current.Spec.VolumeClaimTemplates, desired.Spec.VolumeClaimTemplates)
+	currentHash := current.Annotations[pvcAnnotationHash]
+	desiredHash := desired.Annotations[pvcAnnotationHash]
+
+	return labels.NotEqual(current.Spec.Selector.MatchLabels, desired.Spec.Selector.MatchLabels) || currentHash != desiredHash
 }