Implement server-side apply upgrade & downgrade.

- Allow client-side to server-side apply upgrade.

  Ensure that a user can change management of an object from client-side apply to
  server-side apply without conflicts.

- Allow server-side apply to client-side downgrade.

  For an object managed with client-side apply, a user may upgrade to
  managing the object with server-side apply, then decide to downgrade.

  We can support this downgrade by keeping the last-applied-configuration
  annotation for client-side apply updated with server-side apply.

Author: julianvmodesto

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/BUILD

@@ -6,6 +6,8 @@ go_library(
         "buildmanagerinfo.go",
         "capmanagers.go",
         "fieldmanager.go",
+        "lastappliedmanager.go",
+        "lastappliedupdater.go",
         "managedfieldsupdater.go",
         "skipnonapplied.go",
         "stripmeta.go",
@@ -15,9 +17,11 @@ go_library(
     importpath = "k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager",
     visibility = ["//visibility:public"],
     deps = [
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/meta:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal:go_default_library",
@@ -50,6 +54,8 @@ go_test(
     srcs = [
         "capmanagers_test.go",
         "fieldmanager_test.go",
+        "lastappliedmanager_test.go",
+        "lastappliedupdater_test.go",
         "skipnonapplied_test.go",
     ],
     data = [
@@ -69,6 +75,7 @@ go_test(
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/yaml:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal:go_default_library",
         "//vendor/k8s.io/kube-openapi/pkg/util/proto:go_default_library",
         "//vendor/k8s.io/kube-openapi/pkg/util/proto/testing:go_default_library",

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/capmanagers_test.go

@@ -41,14 +41,16 @@ func (*fakeManager) Update(_, newObj runtime.Object, managed fieldmanager.Manage
 	return newObj, managed, nil
 }
 
-func (*fakeManager) Apply(_, _ runtime.Object, _ fieldmanager.Managed, _ string, force bool) (runtime.Object, fieldmanager.Managed, error) {
+func (*fakeManager) Apply(_, _ runtime.Object, _ fieldmanager.Managed, _ string, _ bool) (runtime.Object, fieldmanager.Managed, error) {
 	panic("not implemented")
 	return nil, nil, nil
 }
 
 func TestCapManagersManagerMergesEntries(t *testing.T) {
-	f := NewTestFieldManager(schema.FromAPIVersionAndKind("v1", "Pod"))
-	f.fieldManager = fieldmanager.NewCapManagersManager(f.fieldManager, 3)
+	f := NewTestFieldManager(schema.FromAPIVersionAndKind("v1", "Pod"),
+		func(m fieldmanager.Manager) fieldmanager.Manager {
+			return fieldmanager.NewCapManagersManager(m, 3)
+		})
 
 	podWithLabels := func(labels ...string) runtime.Object {
 		labelMap := map[string]interface{}{}
@@ -110,8 +112,10 @@ func TestCapManagersManagerMergesEntries(t *testing.T) {
 }
 
 func TestCapUpdateManagers(t *testing.T) {
-	f := NewTestFieldManager(schema.FromAPIVersionAndKind("v1", "Pod"))
-	f.fieldManager = fieldmanager.NewCapManagersManager(&fakeManager{}, 3)
+	f := NewTestFieldManager(schema.FromAPIVersionAndKind("v1", "Pod"),
+		func(m fieldmanager.Manager) fieldmanager.Manager {
+			return fieldmanager.NewCapManagersManager(m, 3)
+		})
 
 	set := func(fields ...string) *metav1.FieldsV1 {
 		s := fieldpath.NewSet()

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/fieldmanager.go

@@ -29,6 +29,7 @@ import (
 	"k8s.io/klog/v2"
 	openapiproto "k8s.io/kube-openapi/pkg/util/proto"
 	"sigs.k8s.io/structured-merge-diff/v3/fieldpath"
+	"sigs.k8s.io/structured-merge-diff/v3/merge"
 )
 
 // DefaultMaxUpdateManagers defines the default maximum retained number of managedFields entries from updates
@@ -78,31 +79,46 @@ func NewFieldManager(f Manager) *FieldManager {
 // NewDefaultFieldManager creates a new FieldManager that merges apply requests
 // and update managed fields for other types of requests.
 func NewDefaultFieldManager(models openapiproto.Models, objectConverter runtime.ObjectConvertor, objectDefaulter runtime.ObjectDefaulter, objectCreater runtime.ObjectCreater, kind schema.GroupVersionKind, hub schema.GroupVersion) (*FieldManager, error) {
-	f, err := NewStructuredMergeManager(models, objectConverter, objectDefaulter, kind.GroupVersion(), hub)
+	typeConverter, err := internal.NewTypeConverter(models, false)
+	if err != nil {
+		return nil, err
+	}
+
+	f, err := NewStructuredMergeManager(typeConverter, objectConverter, objectDefaulter, kind.GroupVersion(), hub)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create field manager: %v", err)
 	}
-	return newDefaultFieldManager(f, objectCreater, kind), nil
+	return newDefaultFieldManager(f, typeConverter, objectConverter, objectCreater, kind), nil
 }
 
 // NewDefaultCRDFieldManager creates a new FieldManager specifically for
 // CRDs. This allows for the possibility of fields which are not defined
 // in models, as well as having no models defined at all.
 func NewDefaultCRDFieldManager(models openapiproto.Models, objectConverter runtime.ObjectConvertor, objectDefaulter runtime.ObjectDefaulter, objectCreater runtime.ObjectCreater, kind schema.GroupVersionKind, hub schema.GroupVersion, preserveUnknownFields bool) (_ *FieldManager, err error) {
-	f, err := NewCRDStructuredMergeManager(models, objectConverter, objectDefaulter, kind.GroupVersion(), hub, preserveUnknownFields)
+	var typeConverter internal.TypeConverter = internal.DeducedTypeConverter{}
+	if models != nil {
+		typeConverter, err = internal.NewTypeConverter(models, preserveUnknownFields)
+		if err != nil {
+			return nil, err
+		}
+	}
+	f, err := NewCRDStructuredMergeManager(typeConverter, objectConverter, objectDefaulter, kind.GroupVersion(), hub, preserveUnknownFields)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create field manager: %v", err)
 	}
-	return newDefaultFieldManager(f, objectCreater, kind), nil
+	return newDefaultFieldManager(f, typeConverter, objectConverter, objectCreater, kind), nil
 }
 
 // newDefaultFieldManager is a helper function which wraps a Manager with certain default logic.
-func newDefaultFieldManager(f Manager, objectCreater runtime.ObjectCreater, kind schema.GroupVersionKind) *FieldManager {
+func newDefaultFieldManager(f Manager, typeConverter internal.TypeConverter, objectConverter runtime.ObjectConvertor, objectCreater runtime.ObjectCreater, kind schema.GroupVersionKind) *FieldManager {
 	f = NewStripMetaManager(f)
 	f = NewManagedFieldsUpdater(f)
 	f = NewBuildManagerInfoManager(f, kind.GroupVersion())
 	f = NewCapManagersManager(f, DefaultMaxUpdateManagers)
 	f = NewProbabilisticSkipNonAppliedManager(f, objectCreater, kind, DefaultTrackOnCreateProbability)
+	f = NewLastAppliedManager(f, typeConverter, objectConverter, kind.GroupVersion())
+	f = NewLastAppliedUpdater(f)
+
 	return NewFieldManager(f)
 }
 
@@ -200,7 +216,11 @@ func (f *FieldManager) Apply(liveObj, appliedObj runtime.Object, manager string,
 
 	internal.RemoveObjectManagedFields(liveObj)
 
-	if object, managed, err = f.fieldManager.Apply(liveObj, appliedObj, managed, manager, force); err != nil {
+	object, managed, err = f.fieldManager.Apply(liveObj, appliedObj, managed, manager, force)
+	if err != nil {
+		if conflicts, ok := err.(merge.Conflicts); ok {
+			return nil, internal.NewConflictError(conflicts)
+		}
 		return nil, err
 	}