Make ordering configurable (#4019)

* api: Add new types for customizeable resource ordering Signed-off-by: Yannis Zarkadas <yanniszark@arrikto.com> * plugins: Implement SortOrderTransformer plugin Implement the SortOrderTransformer plugin. This plugin allows the user to customize the order that kustomize will output resources in. The API for the plugin is the following: sortOptions: order: legacy | fifo legacySortOptions: orderFirst: - {GVK} orderLast: - {GVK} Signed-off-by: Yannis Zarkadas <yanniszark@arrikto.com> * plugins: Add boilerplate and generate code for new SortOrderTransformer Signed-off-by: Yannis Zarkadas <yanniszark@arrikto.com> * build: Add option to denote if the reorder flag was set by the user We want to take different actions if the reorder flag was set by the user or filled by the default value. Thus, we propagate this information from build to the krusty options. Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com> * api/krusty: Ensure sort ordering works with CLI flag and kustomization Sort order can be defined in two places: - (new) kustomization file - (old) CLI flag We want the kustomization file to take precedence over the CLI flag. Eventually, we may want to move away from having a CLI flag altogether: https://github.com/kubernetes-sigs/kustomize/issues/3947 Case 1: Sort order set in kustomization file AND in CLI flag. Print a warning and let the kustomization file take precedence. Case 2: Sort order set in CLI flag only or not at all. Follow the CLI flag (defaults to legacy) and reorder at the end. Case 3: Sort order set in kustomization file only. Simply build the kustomization. Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com> * krusty: Add e2e test for SortOrderTransformer Signed-off-by: Yannis Zarkadas <yanniszark@arrikto.com> * plugins: Purge LegacyOrderTransformer Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com> * Update go.work.sum Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com> * review: Make review changes Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com> Signed-off-by: Yannis Zarkadas <yanniszark@arrikto.com> Signed-off-by: Yannis Zarkadas <yanniszark@gmail.com>
2026-06-13 10:00:56 +00:00 · 2022-12-02 16:59:53 -05:00
parent 1e2e7bbc0b
commit a502717460
30 changed files with 1532 additions and 1092 deletions
--- a/api/builtins/builtins.go
+++ b/api/builtins/builtins.go
@@ -16,7 +16,6 @@ type (
 	IAMPolicyGeneratorPlugin             = internal.IAMPolicyGeneratorPlugin
 	ImageTagTransformerPlugin            = internal.ImageTagTransformerPlugin
 	LabelTransformerPlugin               = internal.LabelTransformerPlugin
-	LegacyOrderTransformerPlugin         = internal.LegacyOrderTransformerPlugin
 	NamespaceTransformerPlugin           = internal.NamespaceTransformerPlugin
 	PatchJson6902TransformerPlugin       = internal.PatchJson6902TransformerPlugin
 	PatchStrategicMergeTransformerPlugin = internal.PatchStrategicMergeTransformerPlugin
@@ -37,7 +36,6 @@ var (
 	NewIAMPolicyGeneratorPlugin             = internal.NewIAMPolicyGeneratorPlugin
 	NewImageTagTransformerPlugin            = internal.NewImageTagTransformerPlugin
 	NewLabelTransformerPlugin               = internal.NewLabelTransformerPlugin
-	NewLegacyOrderTransformerPlugin         = internal.NewLegacyOrderTransformerPlugin
 	NewNamespaceTransformerPlugin           = internal.NewNamespaceTransformerPlugin
 	NewPatchJson6902TransformerPlugin       = internal.NewPatchJson6902TransformerPlugin
 	NewPatchStrategicMergeTransformerPlugin = internal.NewPatchStrategicMergeTransformerPlugin
--- a/api/internal/builtins/LegacyOrderTransformer.go
+++ b/api/internal/builtins/LegacyOrderTransformer.go
@@ -1,46 +0,0 @@
-// Code generated by pluginator on LegacyOrderTransformer; DO NOT EDIT.
-// pluginator {unknown  1970-01-01T00:00:00Z  }
-
-package builtins
-
-import (
-	"sort"
-
-	"github.com/pkg/errors"
-	"sigs.k8s.io/kustomize/api/resmap"
-	"sigs.k8s.io/kustomize/api/resource"
-)
-
-// Sort the resources using an ordering defined in the Gvk class.
-// This puts cluster-wide basic resources with no
-// dependencies (like Namespace, StorageClass, etc.)
-// first, and resources with a high number of dependencies
-// (like ValidatingWebhookConfiguration) last.
-type LegacyOrderTransformerPlugin struct{}
-
-// Nothing needed for configuration.
-func (p *LegacyOrderTransformerPlugin) Config(
-	_ *resmap.PluginHelpers, _ []byte) (err error) {
-	return nil
-}
-
-func (p *LegacyOrderTransformerPlugin) Transform(m resmap.ResMap) (err error) {
-	resources := make([]*resource.Resource, m.Size())
-	ids := m.AllIds()
-	sort.Sort(resmap.IdSlice(ids))
-	for i, id := range ids {
-		resources[i], err = m.GetByCurrentId(id)
-		if err != nil {
-			return errors.Wrap(err, "expected match for sorting")
-		}
-	}
-	m.Clear()
-	for _, r := range resources {
-		m.Append(r)
-	}
-	return nil
-}
-
-func NewLegacyOrderTransformerPlugin() resmap.TransformerPlugin {
-	return &LegacyOrderTransformerPlugin{}
-}
--- a/api/internal/builtins/SortOrderTransformer.go
+++ b/api/internal/builtins/SortOrderTransformer.go
@@ -0,0 +1,244 @@
+// Code generated by pluginator on SortOrderTransformer; DO NOT EDIT.
+// pluginator {unknown  1970-01-01T00:00:00Z  }
+
+package builtins
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/pkg/errors"
+	"sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/resid"
+	"sigs.k8s.io/yaml"
+)
+
+// Sort the resources using a customizable ordering based of Kind.
+// Defaults to the ordering of the GVK struct, which puts cluster-wide basic
+// resources with no dependencies (like Namespace, StorageClass, etc.) first,
+// and resources with a high number of dependencies
+// (like ValidatingWebhookConfiguration) last.
+type SortOrderTransformerPlugin struct {
+	SortOptions *types.SortOptions `json:"sortOptions,omitempty" yaml:"sortOptions,omitempty"`
+}
+
+func (p *SortOrderTransformerPlugin) Config(
+	_ *resmap.PluginHelpers, c []byte) error {
+	return errors.Wrap(yaml.Unmarshal(c, p), "Failed to unmarshal SortOrderTransformer config")
+}
+
+func (p *SortOrderTransformerPlugin) applyDefaults() {
+	// Default to FIFO sort, aka no-op.
+	if p.SortOptions == nil {
+		p.SortOptions = &types.SortOptions{
+			Order: types.FIFOSortOrder,
+		}
+	}
+
+	// If legacy sort is selected and no options are given, default to
+	// hardcoded order.
+	if p.SortOptions.Order == types.LegacySortOrder && p.SortOptions.LegacySortOptions == nil {
+		p.SortOptions.LegacySortOptions = &types.LegacySortOptions{
+			OrderFirst: defaultOrderFirst,
+			OrderLast:  defaultOrderLast,
+		}
+	}
+}
+
+func (p *SortOrderTransformerPlugin) validate() error {
+	// Check valid values for SortOrder
+	if p.SortOptions.Order != types.FIFOSortOrder && p.SortOptions.Order != types.LegacySortOrder {
+		return errors.Errorf("the field 'sortOptions.order' must be one of [%s, %s]",
+			types.FIFOSortOrder, types.LegacySortOrder)
+	}
+
+	// Validate that the only options set are the ones corresponding to the
+	// selected sort order.
+	if p.SortOptions.Order == types.FIFOSortOrder &&
+		p.SortOptions.LegacySortOptions != nil {
+		return errors.Errorf("the field 'sortOptions.legacySortOptions' is"+
+			" set but the selected sort order is '%v', not 'legacy'",
+			p.SortOptions.Order)
+	}
+	return nil
+}
+
+func (p *SortOrderTransformerPlugin) Transform(m resmap.ResMap) (err error) {
+	p.applyDefaults()
+	err = p.validate()
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	// Sort
+	if p.SortOptions.Order == types.LegacySortOrder {
+		s := newLegacyIDSorter(m.AllIds(), p.SortOptions.LegacySortOptions)
+		sort.Sort(s)
+		err = applyOrdering(m, s.resids)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// applyOrdering takes resources (given in ResMap) and a desired ordering given
+// as a sequence of ResIds, and updates the ResMap's resources to match the
+// ordering.
+func applyOrdering(m resmap.ResMap, ordering []resid.ResId) error {
+	var err error
+	resources := make([]*resource.Resource, m.Size())
+	// Clear and refill with the correct order
+	for i, id := range ordering {
+		resources[i], err = m.GetByCurrentId(id)
+		if err != nil {
+			return errors.Wrap(err, "expected match for sorting")
+		}
+	}
+	m.Clear()
+	for _, r := range resources {
+		err = m.Append(r)
+		if err != nil {
+			return errors.Wrap(err, "SortOrderTransformer: Failed to append to resources")
+		}
+	}
+	return nil
+}
+
+// Code for legacy sorting.
+// Legacy sorting is a "fixed" order sorting maintained for backwards
+// compatibility.
+
+// legacyIDSorter sorts resources based on two priority lists:
+// - orderFirst: Resources that should be placed in the start, in the given order.
+// - orderLast: Resources that should be placed in the end, in the given order.
+type legacyIDSorter struct {
+	// resids only stores the metadata of the object. This is an optimization as
+	// it's expensive to compute these again and again during ordering.
+	resids     []resid.ResId
+	typeOrders map[string]int
+}
+
+func newLegacyIDSorter(
+	resids []resid.ResId,
+	options *types.LegacySortOptions) *legacyIDSorter {
+	// Precalculate a resource ranking based on the priority lists.
+	var typeOrders = func() map[string]int {
+		m := map[string]int{}
+		for i, n := range options.OrderFirst {
+			m[n] = -len(options.OrderFirst) + i
+		}
+		for i, n := range options.OrderLast {
+			m[n] = 1 + i
+		}
+		return m
+	}()
+	return &legacyIDSorter{
+		resids:     resids,
+		typeOrders: typeOrders,
+	}
+}
+
+var _ sort.Interface = legacyIDSorter{}
+
+func (a legacyIDSorter) Len() int { return len(a.resids) }
+func (a legacyIDSorter) Swap(i, j int) {
+	a.resids[i], a.resids[j] = a.resids[j], a.resids[i]
+}
+func (a legacyIDSorter) Less(i, j int) bool {
+	if !a.resids[i].Gvk.Equals(a.resids[j].Gvk) {
+		return gvkLessThan(a.resids[i].Gvk, a.resids[j].Gvk, a.typeOrders)
+	}
+	return legacyResIDSortString(a.resids[i]) < legacyResIDSortString(a.resids[j])
+}
+
+func gvkLessThan(gvk1, gvk2 resid.Gvk, typeOrders map[string]int) bool {
+	index1 := typeOrders[gvk1.Kind]
+	index2 := typeOrders[gvk2.Kind]
+	if index1 != index2 {
+		return index1 < index2
+	}
+	return legacyGVKSortString(gvk1) < legacyGVKSortString(gvk2)
+}
+
+// legacyGVKSortString returns a string representation of given GVK used for
+// stable sorting.
+func legacyGVKSortString(x resid.Gvk) string {
+	legacyNoGroup := "~G"
+	legacyNoVersion := "~V"
+	legacyNoKind := "~K"
+	legacyFieldSeparator := "_"
+
+	g := x.Group
+	if g == "" {
+		g = legacyNoGroup
+	}
+	v := x.Version
+	if v == "" {
+		v = legacyNoVersion
+	}
+	k := x.Kind
+	if k == "" {
+		k = legacyNoKind
+	}
+	return strings.Join([]string{g, v, k}, legacyFieldSeparator)
+}
+
+// legacyResIDSortString returns a string representation of given ResID used for
+// stable sorting.
+func legacyResIDSortString(id resid.ResId) string {
+	legacyNoNamespace := "~X"
+	legacyNoName := "~N"
+	legacySeparator := "|"
+
+	ns := id.Namespace
+	if ns == "" {
+		ns = legacyNoNamespace
+	}
+	nm := id.Name
+	if nm == "" {
+		nm = legacyNoName
+	}
+	return strings.Join(
+		[]string{id.Gvk.String(), ns, nm}, legacySeparator)
+}
+
+// DO NOT CHANGE!
+// Final legacy ordering provided as a default by kustomize.
+// Originally an attempt to apply resources in the correct order, an effort
+// which later proved impossible as not all types are known beforehand.
+// See: https://github.com/kubernetes-sigs/kustomize/issues/3913
+var defaultOrderFirst = []string{ //nolint:gochecknoglobals
+	"Namespace",
+	"ResourceQuota",
+	"StorageClass",
+	"CustomResourceDefinition",
+	"ServiceAccount",
+	"PodSecurityPolicy",
+	"Role",
+	"ClusterRole",
+	"RoleBinding",
+	"ClusterRoleBinding",
+	"ConfigMap",
+	"Secret",
+	"Endpoints",
+	"Service",
+	"LimitRange",
+	"PriorityClass",
+	"PersistentVolume",
+	"PersistentVolumeClaim",
+	"Deployment",
+	"StatefulSet",
+	"CronJob",
+	"PodDisruptionBudget",
+}
+var defaultOrderLast = []string{ //nolint:gochecknoglobals
+	"MutatingWebhookConfiguration",
+	"ValidatingWebhookConfiguration",
+}
+
+func NewSortOrderTransformerPlugin() resmap.TransformerPlugin {
+	return &SortOrderTransformerPlugin{}
+}
--- a/api/internal/plugins/builtinhelpers/builtinplugintype_string.go
+++ b/api/internal/plugins/builtinhelpers/builtinplugintype_string.go
@@ -15,24 +15,23 @@ func _() {
 	_ = x[HashTransformer-4]
 	_ = x[ImageTagTransformer-5]
 	_ = x[LabelTransformer-6]
-	_ = x[LegacyOrderTransformer-7]
-	_ = x[NamespaceTransformer-8]
-	_ = x[PatchJson6902Transformer-9]
-	_ = x[PatchStrategicMergeTransformer-10]
-	_ = x[PatchTransformer-11]
-	_ = x[PrefixSuffixTransformer-12]
-	_ = x[PrefixTransformer-13]
-	_ = x[SuffixTransformer-14]
-	_ = x[ReplicaCountTransformer-15]
-	_ = x[SecretGenerator-16]
-	_ = x[ValueAddTransformer-17]
-	_ = x[HelmChartInflationGenerator-18]
-	_ = x[ReplacementTransformer-19]
+	_ = x[NamespaceTransformer-7]
+	_ = x[PatchJson6902Transformer-8]
+	_ = x[PatchStrategicMergeTransformer-9]
+	_ = x[PatchTransformer-10]
+	_ = x[PrefixSuffixTransformer-11]
+	_ = x[PrefixTransformer-12]
+	_ = x[SuffixTransformer-13]
+	_ = x[ReplicaCountTransformer-14]
+	_ = x[SecretGenerator-15]
+	_ = x[ValueAddTransformer-16]
+	_ = x[HelmChartInflationGenerator-17]
+	_ = x[ReplacementTransformer-18]
 }

-const _BuiltinPluginType_name = "UnknownAnnotationsTransformerConfigMapGeneratorIAMPolicyGeneratorHashTransformerImageTagTransformerLabelTransformerLegacyOrderTransformerNamespaceTransformerPatchJson6902TransformerPatchStrategicMergeTransformerPatchTransformerPrefixSuffixTransformerPrefixTransformerSuffixTransformerReplicaCountTransformerSecretGeneratorValueAddTransformerHelmChartInflationGeneratorReplacementTransformer"
+const _BuiltinPluginType_name = "UnknownAnnotationsTransformerConfigMapGeneratorIAMPolicyGeneratorHashTransformerImageTagTransformerLabelTransformerNamespaceTransformerPatchJson6902TransformerPatchStrategicMergeTransformerPatchTransformerPrefixSuffixTransformerPrefixTransformerSuffixTransformerReplicaCountTransformerSecretGeneratorValueAddTransformerHelmChartInflationGeneratorReplacementTransformer"

-var _BuiltinPluginType_index = [...]uint16{0, 7, 29, 47, 65, 80, 99, 115, 137, 157, 181, 211, 227, 250, 267, 284, 307, 322, 341, 368, 390}
+var _BuiltinPluginType_index = [...]uint16{0, 7, 29, 47, 65, 80, 99, 115, 135, 159, 189, 205, 228, 245, 262, 285, 300, 319, 346, 368}

 func (i BuiltinPluginType) String() string {
 	if i < 0 || i >= BuiltinPluginType(len(_BuiltinPluginType_index)-1) {
--- a/api/internal/plugins/builtinhelpers/builtins.go
+++ b/api/internal/plugins/builtinhelpers/builtins.go
@@ -19,7 +19,6 @@ const (
 	HashTransformer
 	ImageTagTransformer
 	LabelTransformer
-	LegacyOrderTransformer
 	NamespaceTransformer
 	PatchJson6902Transformer
 	PatchStrategicMergeTransformer
@@ -100,7 +99,6 @@ var TransformerFactories = map[BuiltinPluginType]func() resmap.TransformerPlugin
 	HashTransformer:                builtins.NewHashTransformerPlugin,
 	ImageTagTransformer:            builtins.NewImageTagTransformerPlugin,
 	LabelTransformer:               builtins.NewLabelTransformerPlugin,
-	LegacyOrderTransformer:         builtins.NewLegacyOrderTransformerPlugin,
 	NamespaceTransformer:           builtins.NewNamespaceTransformerPlugin,
 	PatchJson6902Transformer:       builtins.NewPatchJson6902TransformerPlugin,
 	PatchStrategicMergeTransformer: builtins.NewPatchStrategicMergeTransformerPlugin,
@@ -111,4 +109,7 @@ var TransformerFactories = map[BuiltinPluginType]func() resmap.TransformerPlugin
 	ReplacementTransformer:         builtins.NewReplacementTransformerPlugin,
 	ReplicaCountTransformer:        builtins.NewReplicaCountTransformerPlugin,
 	ValueAddTransformer:            builtins.NewValueAddTransformerPlugin,
+	// Do not wired SortOrderTransformer as a builtin plugin.
+	// We only want it to be available in the top-level kustomization.
+	// See: https://github.com/kubernetes-sigs/kustomize/issues/3913
 }
--- a/api/krusty/kustomizer.go
+++ b/api/krusty/kustomizer.go
@@ -5,6 +5,7 @@ package krusty

 import (
 	"fmt"
+	"log"

 	"sigs.k8s.io/kustomize/api/internal/builtins"
 	pLdr "sigs.k8s.io/kustomize/api/internal/plugins/loader"
@@ -90,11 +91,9 @@ func (b *Kustomizer) Run(
 	if err != nil {
 		return nil, err
 	}
-	if b.options.DoLegacyResourceSort {
-		err = builtins.NewLegacyOrderTransformerPlugin().Transform(m)
-		if err != nil {
-			return nil, err
-		}
+	err = b.applySortOrder(m, kt)
+	if err != nil {
+		return nil, err
 	}
 	if b.options.AddManagedbyLabel || utils.StringSliceContains(kt.Kustomization().BuildMetadata, types.ManagedByLabelOption) {
 		t := builtins.LabelTransformerPlugin{
@@ -126,3 +125,39 @@ func (b *Kustomizer) Run(
 	}
 	return m, nil
 }
+
+func (b *Kustomizer) applySortOrder(m resmap.ResMap, kt *target.KustTarget) error {
+	// Sort order can be defined in two places:
+	// - (new) kustomization file
+	// - (old) CLI flag
+	//
+	// We want the kustomization file to take precedence over the CLI flag.
+	// Eventually, we may want to move away from having a CLI flag altogether:
+	// https://github.com/kubernetes-sigs/kustomize/issues/3947
+
+	// Case 1: Sort order set in kustomization file.
+	if kt.Kustomization().SortOptions != nil {
+		// If set in CLI flag too, warn the user.
+		if b.options.Reorder != ReorderOptionUnspecified {
+			log.Println("Warning: Sorting order is set both in 'kustomization.yaml'" +
+				" ('sortOptions') and in a CLI flag ('--reorder'). Using the" +
+				" kustomization file over the CLI flag.")
+		}
+		pl := &builtins.SortOrderTransformerPlugin{
+			SortOptions: kt.Kustomization().SortOptions,
+		}
+		err := pl.Transform(m)
+		if err != nil {
+			return errors.Wrap(err)
+		}
+	} else if b.options.Reorder == ReorderOptionLegacy || b.options.Reorder == ReorderOptionUnspecified {
+		// Case 2: Sort order set in CLI flag only or not at all.
+		pl := &builtins.SortOrderTransformerPlugin{
+			SortOptions: &types.SortOptions{
+				Order: types.LegacySortOrder,
+			},
+		}
+		return errors.Wrap(pl.Transform(m))
+	}
+	return nil
+}
--- a/api/krusty/legacy_order_test.go
+++ b/api/krusty/legacy_order_test.go
@@ -6,6 +6,7 @@ package krusty_test
 import (
 	"testing"

+	"sigs.k8s.io/kustomize/api/krusty"
 	kusttest_test "sigs.k8s.io/kustomize/api/testutils/kusttest"
 )

@@ -38,7 +39,7 @@ data:
  key: value
 `)
 	opts := th.MakeDefaultOptions()
-	opts.DoLegacyResourceSort = true
+	opts.Reorder = krusty.ReorderOptionLegacy
 	m := th.Run(".", opts)
 	th.AssertActualEqualsExpected(m, `
 apiVersion: v1
--- a/api/krusty/options.go
+++ b/api/krusty/options.go
@@ -8,6 +8,14 @@ import (
 	"sigs.k8s.io/kustomize/api/types"
 )

+type ReorderOption string
+
+const (
+	ReorderOptionLegacy      ReorderOption = "legacy"
+	ReorderOptionNone        ReorderOption = "none"
+	ReorderOptionUnspecified ReorderOption = "unspecified"
+)
+
 // Options holds high-level kustomize configuration options,
 // e.g. are plugins enabled, should the loader be restricted
 // to the kustomization root, etc.
@@ -16,7 +24,15 @@ type Options struct {
 	// per a particular sort order.  When false, don't do the
 	// sort, and instead respect the depth-first resource input
 	// order as specified by the kustomization file(s).
-	DoLegacyResourceSort bool
+
+	// Sort the resources before emitting them. Possible values:
+	// - "legacy": Use a fixed order that kustomize provides for backwards
+	//   compatibility.
+	// - "none": Respect the depth-first resource input order as specified by the
+	//   kustomization file.
+	// - "unspecified": The user didn't specify any preference. Kustomize will
+	//   select the appropriate default.
+	Reorder ReorderOption

 	// When true, a label
 	//     app.kubernetes.io/managed-by: kustomize-<version>
@@ -37,11 +53,11 @@ type Options struct {
 // MakeDefaultOptions returns a default instance of Options.
 func MakeDefaultOptions() *Options {
 	return &Options{
-		DoLegacyResourceSort: false,
-		AddManagedbyLabel:    false,
-		LoadRestrictions:     types.LoadRestrictionsRootOnly,
-		DoPrune:              false,
-		PluginConfig:         types.DisabledPluginConfig(),
+		Reorder:           ReorderOptionNone,
+		AddManagedbyLabel: false,
+		LoadRestrictions:  types.LoadRestrictionsRootOnly,
+		DoPrune:           false,
+		PluginConfig:      types.DisabledPluginConfig(),
 	}
 }

--- a/api/krusty/sortordertransformer_test.go
+++ b/api/krusty/sortordertransformer_test.go
@@ -0,0 +1,331 @@
+// Copyright 2022 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package krusty_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"sigs.k8s.io/kustomize/api/krusty"
+	kusttest_test "sigs.k8s.io/kustomize/api/testutils/kusttest"
+)
+
+//nolint:gochecknoglobals
+var sortOrderResources = `
+apiVersion: v1
+kind: Service
+metadata:
+  name: papaya
+---
+apiVersion: v1
+kind: Role
+metadata:
+  name: banana
+---
+apiVersion: v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: pomegranate
+---
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: peach
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: pear
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: apple
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: quince
+---
+apiVersion: v1
+kind: Ingress
+metadata:
+  name: durian
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: apricot
+`
+
+//nolint:gochecknoglobals
+var legacyOrderResources = `
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: apple
+---
+apiVersion: v1
+kind: Role
+metadata:
+  name: banana
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: apricot
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: quince
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: papaya
+---
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: peach
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: pear
+---
+apiVersion: v1
+kind: Ingress
+metadata:
+  name: durian
+---
+apiVersion: v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: pomegranate
+`
+
+func TestCustomOrdering(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: legacy
+  legacySortOptions:
+    orderFirst:
+    - MutatingWebhookConfiguration
+    - ValidatingWebhookConfiguration
+    - ResourceQuota
+    - StorageClass
+    - CustomResourceDefinition
+    - ServiceAccount
+    - PodSecurityPolicy
+    - Role
+    - ClusterRole
+    - RoleBinding
+    - ClusterRoleBinding
+    - ConfigMap
+    - Secret
+    - Endpoints
+    - Service
+    - LimitRange
+    - PriorityClass
+    - PersistentVolume
+    - PersistentVolumeClaim
+    - StatefulSet
+    - CronJob
+    - PodDisruptionBudget
+    orderLast:
+    - Namespace
+    - Deployment
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+
+	th.AssertActualEqualsExpected(
+		th.Run("base", th.MakeDefaultOptions()),
+		`
+apiVersion: v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: pomegranate
+---
+apiVersion: v1
+kind: Role
+metadata:
+  name: banana
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: apricot
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: quince
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: papaya
+---
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: peach
+---
+apiVersion: v1
+kind: Ingress
+metadata:
+  name: durian
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: apple
+---
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: pear
+`)
+}
+
+func TestDefaultLegacyOrdering(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: legacy
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	th.AssertActualEqualsExpected(
+		th.Run("base", th.MakeDefaultOptions()), legacyOrderResources)
+}
+
+func TestFIFOOrdering(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: fifo
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	th.AssertActualEqualsExpected(
+		th.Run("base", th.MakeDefaultOptions()), sortOrderResources)
+}
+
+func TestInvalidLegacySortOptionsWithoutOrderKey(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  legacySortOptions: {}
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	err := th.RunWithErr("base", th.MakeDefaultOptions())
+	require.ErrorContains(t, err, "the field 'sortOptions.order' must be one of [fifo, legacy]")
+}
+
+func TestInvalidLegacySortOptionsWithFIFOOrder(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: fifo
+  legacySortOptions: {}
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	err := th.RunWithErr("base", th.MakeDefaultOptions())
+	require.ErrorContains(t, err, "the field 'sortOptions.legacySortOptions' is set but the selected sort order is 'fifo', not 'legacy'")
+}
+
+// If the sort order is defined both in a CLI flag and the kustomization file,
+// the kustomization file takes precedence.
+func TestCLIAndKustomizationSet(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: fifo
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	kustOptions := th.MakeDefaultOptions()
+	kustOptions.Reorder = krusty.ReorderOptionLegacy
+	th.AssertActualEqualsExpected(th.Run("base", kustOptions), sortOrderResources)
+}
+
+// If no sort order is set in the kustomization file, validate that we fallback
+// to the default legacy sort ordering.
+func TestKustomizationSortOrderNotSet(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	kustOptions := th.MakeDefaultOptions()
+	kustOptions.Reorder = krusty.ReorderOptionUnspecified
+	th.AssertActualEqualsExpected(th.Run("base", kustOptions), legacyOrderResources)
+}
+
+func TestChildKustomizationSortOrder(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+sortOptions:
+  order: legacy
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	th.WriteK("overlay", `
+resources:
+- ../base
+
+sortOptions:
+  order: fifo
+`)
+
+	kustOptions := th.MakeDefaultOptions()
+	// If child kustomization ordering takes effect, the order will be legacy,
+	// otherwise fifo.
+	th.AssertActualEqualsExpected(th.Run("overlay", kustOptions), sortOrderResources)
+}
+
+func TestSortOrderGivenAsTransformer(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK("base", `
+resources:
+- resources.yaml
+
+transformers:
+- sort_order.yaml
+`)
+	th.WriteF("base/resources.yaml", sortOrderResources)
+	th.WriteF("base/sort_order.yaml", `
+apiVersion: builtin
+kind: SortOrderTransformer
+metadata:
+  name: notImportantHere
+sortOptions:
+  order: fifo`)
+
+	kustOptions := th.MakeDefaultOptions()
+	err := th.RunWithErr("base", kustOptions)
+	require.ErrorContains(t, err, "unable to load builtin SortOrderTransformer.builtin.[noGrp]")
+}
--- a/api/resmap/idslice.go
+++ b/api/resmap/idslice.go
@@ -1,37 +0,0 @@
-/*
-Copyright 2018 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package resmap
-
-import (
-	"sort"
-
-	"sigs.k8s.io/kustomize/kyaml/resid"
-)
-
-// IdSlice implements the sort interface.
-type IdSlice []resid.ResId
-
-var _ sort.Interface = IdSlice{}
-
-func (a IdSlice) Len() int      { return len(a) }
-func (a IdSlice) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
-func (a IdSlice) Less(i, j int) bool {
-	if !a[i].Gvk.Equals(a[j].Gvk) {
-		return a[i].Gvk.IsLessThan(a[j].Gvk)
-	}
-	return a[i].LegacySortString() < a[j].LegacySortString()
-}
--- a/api/resmap/idslice_test.go
+++ b/api/resmap/idslice_test.go
@@ -1,52 +0,0 @@
-/*
-Copyright 2018 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package resmap
-
-import (
-	"reflect"
-	"sort"
-	"testing"
-
-	"sigs.k8s.io/kustomize/kyaml/resid"
-)
-
-func TestLess(t *testing.T) {
-	ids := IdSlice{
-		resid.NewResIdKindOnly("ConfigMap", "cm"),
-		resid.NewResIdKindOnly("Pod", "pod"),
-		resid.NewResIdKindOnly("Namespace", "ns1"),
-		resid.NewResIdKindOnly("Namespace", "ns2"),
-		resid.NewResIdKindOnly("Role", "ro"),
-		resid.NewResIdKindOnly("RoleBinding", "rb"),
-		resid.NewResIdKindOnly("CustomResourceDefinition", "crd"),
-		resid.NewResIdKindOnly("ServiceAccount", "sa"),
-	}
-	expected := IdSlice{
-		resid.NewResIdKindOnly("Namespace", "ns1"),
-		resid.NewResIdKindOnly("Namespace", "ns2"),
-		resid.NewResIdKindOnly("CustomResourceDefinition", "crd"),
-		resid.NewResIdKindOnly("ServiceAccount", "sa"),
-		resid.NewResIdKindOnly("Role", "ro"),
-		resid.NewResIdKindOnly("RoleBinding", "rb"),
-		resid.NewResIdKindOnly("ConfigMap", "cm"),
-		resid.NewResIdKindOnly("Pod", "pod"),
-	}
-	sort.Sort(ids)
-	if !reflect.DeepEqual(ids, expected) {
-		t.Fatalf("expected %+v but got %+v", expected, ids)
-	}
-}
--- a/api/types/kustomization.go
+++ b/api/types/kustomization.go
@@ -101,6 +101,9 @@ type Kustomization struct {
 	// value of the specified field has been determined.
 	Vars []Var `json:"vars,omitempty" yaml:"vars,omitempty"`

+	// SortOptions change the order that kustomize outputs resources.
+	SortOptions *SortOptions `json:"sortOptions,omitempty" yaml:"sortOptions,omitempty"`
+
 	//
 	// Operands - what kustomize operates on.
 	//
--- a/api/types/sortoptions.go
+++ b/api/types/sortoptions.go
@@ -0,0 +1,28 @@
+// Copyright 2021 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package types
+
+// SortOptions defines the order that kustomize outputs resources.
+type SortOptions struct {
+	// Order selects the ordering strategy.
+	Order SortOrder `json:"order,omitempty" yaml:"order,omitempty"`
+	// LegacySortOptions tweaks the sorting for the "legacy" sort ordering
+	// strategy.
+	LegacySortOptions *LegacySortOptions `json:"legacySortOptions,omitempty" yaml:"legacySortOptions,omitempty"`
+}
+
+// SortOrder defines different ordering strategies.
+type SortOrder string
+
+const LegacySortOrder SortOrder = "legacy"
+const FIFOSortOrder SortOrder = "fifo"
+
+// LegacySortOptions define various options for tweaking the "legacy" ordering
+// strategy.
+type LegacySortOptions struct {
+	// OrderFirst selects the resource kinds to order first.
+	OrderFirst []string `json:"orderFirst" yaml:"orderFirst"`
+	// OrderLast selects the resource kinds to order last.
+	OrderLast []string `json:"orderLast" yaml:"orderLast"`
+}