feat: add bond slaves ordering

Before this change, we didn't preserve bonded interfaces ordering, which caused problems in some scenarios. Fix this by remembering their position in the original config.

Fixes #5207.

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

internal/app/machined/pkg/controllers/network/cmdline.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/talos-systems/talos/pkg/machinery/config/types/v1alpha1"
 	"github.com/talos-systems/talos/pkg/machinery/constants"
+	"github.com/talos-systems/talos/pkg/machinery/ordered"
 	"github.com/talos-systems/talos/pkg/machinery/resources/network"
 )
 
@@ -244,13 +245,13 @@ func ParseCmdlineNetwork(cmdline *procfs.Cmdline) (CmdlineNetworking, error) {
 
 		linkSpecSpecs = append(linkSpecSpecs, bondLinkSpec)
 
-		for _, slave := range bondSlaves {
+		for idx, slave := range bondSlaves {
 			slaveLinkSpec := network.LinkSpecSpec{
 				Name:        slave,
 				Up:          true,
 				ConfigLayer: network.ConfigCmdline,
 			}
-			SetBondSlave(&slaveLinkSpec, bondName)
+			SetBondSlave(&slaveLinkSpec, ordered.MakePair(bondName, idx))
 			linkSpecSpecs = append(linkSpecSpecs, slaveLinkSpec)
 		}
 	}

internal/app/machined/pkg/controllers/network/cmdline_test.go

@@ -63,14 +63,20 @@ func (suite *CmdlineSuite) TestParse() {
 				Up:          true,
 				Logical:     false,
 				ConfigLayer: netconfig.ConfigCmdline,
+				BondSlave: netconfig.BondSlave{
 					MasterName: "bond0",
+					SlaveIndex: 0,
+				},
 			},
 			{
 				Name:        "eth1",
 				Up:          true,
 				Logical:     false,
 				ConfigLayer: netconfig.ConfigCmdline,
+				BondSlave: netconfig.BondSlave{
 					MasterName: "bond0",
+					SlaveIndex: 1,
+				},
 			},
 		},
 	}
@@ -233,14 +239,20 @@ func (suite *CmdlineSuite) TestParse() {
 						Up:          true,
 						Logical:     false,
 						ConfigLayer: netconfig.ConfigCmdline,
+						BondSlave: netconfig.BondSlave{
 							MasterName: "bond1",
+							SlaveIndex: 0,
+						},
 					},
 					{
 						Name:        "eth4",
 						Up:          true,
 						Logical:     false,
 						ConfigLayer: netconfig.ConfigCmdline,
+						BondSlave: netconfig.BondSlave{
 							MasterName: "bond1",
+							SlaveIndex: 1,
+						},
 					},
 				},
 			},
@@ -275,14 +287,20 @@ func (suite *CmdlineSuite) TestParse() {
 						Up:          true,
 						Logical:     false,
 						ConfigLayer: netconfig.ConfigCmdline,
+						BondSlave: netconfig.BondSlave{
 							MasterName: "bond1",
+							SlaveIndex: 0,
+						},
 					},
 					{
 						Name:        "eth4",
 						Up:          true,
 						Logical:     false,
 						ConfigLayer: netconfig.ConfigCmdline,
+						BondSlave: netconfig.BondSlave{
 							MasterName: "bond1",
+							SlaveIndex: 1,
+						},
 					},
 				},
 			},

internal/app/machined/pkg/controllers/network/link_config.go

@@ -18,6 +18,7 @@ import (
 
 	talosconfig "github.com/talos-systems/talos/pkg/machinery/config"
 	"github.com/talos-systems/talos/pkg/machinery/nethelpers"
+	"github.com/talos-systems/talos/pkg/machinery/ordered"
 	"github.com/talos-systems/talos/pkg/machinery/resources/config"
 	"github.com/talos-systems/talos/pkg/machinery/resources/network"
 )
@@ -269,7 +270,7 @@ func (ctrl *LinkConfigController) parseCmdline(logger *zap.Logger) ([]network.Li
 //nolint:gocyclo
 func (ctrl *LinkConfigController) parseMachineConfiguration(logger *zap.Logger, cfgProvider talosconfig.Provider) []network.LinkSpecSpec {
 	// scan for the bonds
-	bondedLinks := map[string]string{} // mapping physical interface -> bond interface
+	bondedLinks := map[string]ordered.Pair[string, int]{} // mapping physical interface -> bond interface
 
 	for _, device := range cfgProvider.Machine().Network().Devices() {
 		if device.Ignore() {
@@ -280,12 +281,12 @@ func (ctrl *LinkConfigController) parseMachineConfiguration(logger *zap.Logger,
 			continue
 		}
 
-		for _, linkName := range device.Bond().Interfaces() {
+		for idx, linkName := range device.Bond().Interfaces() {
-			if bondName, exists := bondedLinks[linkName]; exists && bondName != device.Interface() {
+			if bondData, exists := bondedLinks[linkName]; exists && bondData.F1 != device.Interface() {
 				logger.Sugar().Warnf("link %q is included into more than two bonds", linkName)
 			}
 
-			bondedLinks[linkName] = device.Interface()
+			bondedLinks[linkName] = ordered.MakePair(device.Interface(), idx)
 		}
 	}
 
@@ -331,7 +332,7 @@ func (ctrl *LinkConfigController) parseMachineConfiguration(logger *zap.Logger,
 		}
 	}
 
-	for slaveName, bondName := range bondedLinks {
+	for slaveName, bondData := range bondedLinks {
 		if _, exists := linkMap[slaveName]; !exists {
 			linkMap[slaveName] = &network.LinkSpecSpec{
 				Name:        slaveName,
@@ -340,7 +341,7 @@ func (ctrl *LinkConfigController) parseMachineConfiguration(logger *zap.Logger,
 			}
 		}
 
-		SetBondSlave(linkMap[slaveName], bondName)
+		SetBondSlave(linkMap[slaveName], bondData)
 	}
 
 	links := make([]network.LinkSpecSpec, 0, len(linkMap))

internal/app/machined/pkg/controllers/network/link_config_test.go

@@ -316,7 +316,7 @@ func (suite *LinkConfigSuite) TestMachineConfiguration() {
 						case "eth2", "eth3":
 							suite.Assert().True(r.TypedSpec().Up)
 							suite.Assert().False(r.TypedSpec().Logical)
-							suite.Assert().Equal("bond0", r.TypedSpec().MasterName)
+							suite.Assert().Equal("bond0", r.TypedSpec().BondSlave.MasterName)
 						case "bond0":
 							suite.Assert().True(r.TypedSpec().Up)
 							suite.Assert().True(r.TypedSpec().Logical)

internal/app/machined/pkg/controllers/network/link_spec.go

@@ -7,6 +7,7 @@ package network
 import (
 	"context"
 	"fmt"
+	"sort"
 
 	"github.com/AlekSi/pointer"
 	"github.com/cosi-project/runtime/pkg/controller"
@@ -20,6 +21,7 @@ import (
 	networkadapter "github.com/talos-systems/talos/internal/app/machined/pkg/adapters/network"
 	"github.com/talos-systems/talos/internal/app/machined/pkg/controllers/network/watch"
 	"github.com/talos-systems/talos/pkg/machinery/nethelpers"
+	"github.com/talos-systems/talos/pkg/machinery/ordered"
 	"github.com/talos-systems/talos/pkg/machinery/resources/network"
 )
 
@@ -111,6 +113,8 @@ func (ctrl *LinkSpecController) Run(ctx context.Context, r controller.Runtime, l
 		// loop over links and make reconcile decision
 		var multiErr *multierror.Error
 
+		SortBonds(list.Items)
+
 		for _, res := range list.Items {
 			link := res.(*network.LinkSpec) //nolint:forcetypeassert,errcheck
 
@@ -125,6 +129,27 @@ func (ctrl *LinkSpecController) Run(ctx context.Context, r controller.Runtime, l
 	}
 }
 
+// SortBonds sort resources in increasing order, except it places slave interfaces right after the bond
+// in proper order.
+func SortBonds(items []resource.Resource) {
+	sort.Slice(items, func(i, j int) bool {
+		left := items[i].Spec().(network.LinkSpecSpec)  //nolint:errcheck
+		right := items[j].Spec().(network.LinkSpecSpec) //nolint:errcheck
+
+		l := ordered.MakeTriple(left.Name, 0, "")
+		if left.BondSlave.MasterName != "" {
+			l = ordered.MakeTriple(left.BondSlave.MasterName, left.BondSlave.SlaveIndex, left.Name)
+		}
+
+		r := ordered.MakeTriple(right.Name, 0, "")
+		if right.BondSlave.MasterName != "" {
+			r = ordered.MakeTriple(right.BondSlave.MasterName, right.BondSlave.SlaveIndex, right.Name)
+		}
+
+		return l.LessThan(r)
+	})
+}
+
 func findLink(links []rtnetlink.LinkMessage, name string) *rtnetlink.LinkMessage {
 	for i, link := range links {
 		if link.Attributes.Name == name {
@@ -341,7 +366,7 @@ func (ctrl *LinkSpecController) syncLink(ctx context.Context, r controller.Runti
 								Master: pointer.ToUint32(0),
 							},
 						}); err != nil {
-							return fmt.Errorf("error unslaving link %q under %q: %w", slave.Attributes.Name, link.TypedSpec().MasterName, err)
+							return fmt.Errorf("error unslaving link %q under %q: %w", slave.Attributes.Name, link.TypedSpec().BondSlave.MasterName, err)
 						}
 
 						(*links)[i].Attributes.Master = nil
@@ -448,8 +473,8 @@ func (ctrl *LinkSpecController) syncLink(ctx context.Context, r controller.Runti
 		// sync master index (for links which are bond slaves)
 		var masterIndex uint32
 
-		if link.TypedSpec().MasterName != "" {
+		if link.TypedSpec().BondSlave.MasterName != "" {
-			if master := findLink(*links, link.TypedSpec().MasterName); master != nil {
+			if master := findLink(*links, link.TypedSpec().BondSlave.MasterName); master != nil {
 				masterIndex = master.Index
 			}
 		}
@@ -464,12 +489,12 @@ func (ctrl *LinkSpecController) syncLink(ctx context.Context, r controller.Runti
 					Master: pointer.ToUint32(masterIndex),
 				},
 			}); err != nil {
-				return fmt.Errorf("error enslaving/unslaving link %q under %q: %w", link.TypedSpec().Name, link.TypedSpec().MasterName, err)
+				return fmt.Errorf("error enslaving/unslaving link %q under %q: %w", link.TypedSpec().Name, link.TypedSpec().BondSlave.MasterName, err)
 			}
 
 			existing.Attributes.Master = pointer.ToUint32(masterIndex)
 
-			logger.Info("enslaved/unslaved link", zap.String("parent", link.TypedSpec().MasterName))
+			logger.Info("enslaved/unslaved link", zap.String("parent", link.TypedSpec().BondSlave.MasterName))
 		}
 	}
 

internal/app/machined/pkg/controllers/network/link_spec_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/cosi-project/runtime/pkg/state"
 	"github.com/cosi-project/runtime/pkg/state/impl/inmem"
 	"github.com/cosi-project/runtime/pkg/state/impl/namespaced"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 	"github.com/talos-systems/go-retry/retry"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
@@ -376,7 +377,10 @@ func (suite *LinkSpecSuite) TestBond() {
 		Kind:    "dummy",
 		Up:      true,
 		Logical: true,
+		BondSlave: network.BondSlave{
 			MasterName: bondName,
+			SlaveIndex: 0,
+		},
 		ConfigLayer: network.ConfigDefault,
 	}
 
@@ -388,7 +392,10 @@ func (suite *LinkSpecSuite) TestBond() {
 		Kind:    "dummy",
 		Up:      true,
 		Logical: true,
+		BondSlave: network.BondSlave{
 			MasterName: bondName,
+			SlaveIndex: 1,
+		},
 		ConfigLayer: network.ConfigDefault,
 	}
 
@@ -460,7 +467,7 @@ func (suite *LinkSpecSuite) TestBond() {
 	// unslave one of the interfaces
 	_, err = suite.state.UpdateWithConflicts(
 		suite.ctx, dummy0.Metadata(), func(r resource.Resource) error {
-			r.(*network.LinkSpec).TypedSpec().MasterName = ""
+			r.(*network.LinkSpec).TypedSpec().BondSlave.MasterName = ""
 
 			return nil
 		},
@@ -538,7 +545,10 @@ func (suite *LinkSpecSuite) TestBond8023ad() {
 			Kind:    "dummy",
 			Up:      true,
 			Logical: true,
+			BondSlave: network.BondSlave{
 				MasterName: bondName,
+				SlaveIndex: 0,
+			},
 			ConfigLayer: network.ConfigDefault,
 		}
 
@@ -743,3 +753,72 @@ func (suite *LinkSpecSuite) TearDownTest() {
 func TestLinkSpecSuite(t *testing.T) {
 	suite.Run(t, new(LinkSpecSuite))
 }
+
+func TestSortBonds(t *testing.T) {
+	expectedSlice := []network.LinkSpecSpec{
+		{
+			Name: "A",
+		}, {
+			Name: "G",
+			BondSlave: network.BondSlave{
+				MasterName: "A",
+				SlaveIndex: 0,
+			},
+		}, {
+			Name: "C",
+		}, {
+			Name: "E",
+			BondSlave: network.BondSlave{
+				MasterName: "C",
+				SlaveIndex: 0,
+			},
+		}, {
+			Name: "F",
+			BondSlave: network.BondSlave{
+				MasterName: "C",
+				SlaveIndex: 1,
+			},
+		}, {
+			Name: "B",
+			BondSlave: network.BondSlave{
+				MasterName: "C",
+				SlaveIndex: 2,
+			},
+		},
+	}
+
+	seed := time.Now().Unix()
+	rnd := rand.New(rand.NewSource(seed))
+
+	for i := 0; i < 100; i++ {
+		res := toResources(expectedSlice)
+		rnd.Shuffle(len(res), func(i, j int) { res[i], res[j] = res[j], res[i] })
+		netctrl.SortBonds(res)
+		sorted := toSpecs(res)
+		require.Equal(t, expectedSlice, sorted, "failed with seed %d iteration %d", seed, i)
+	}
+}
+
+func toResources(slice []network.LinkSpecSpec) []resource.Resource {
+	result := make([]resource.Resource, 0, len(slice))
+
+	for _, elem := range slice {
+		link := network.NewLinkSpec(network.NamespaceName, "bar")
+		*link.TypedSpec() = elem
+
+		result = append(result, link)
+	}
+
+	return result
+}
+
+func toSpecs(slice []resource.Resource) []network.LinkSpecSpec {
+	result := make([]network.LinkSpecSpec, 0, len(slice))
+
+	for _, elem := range slice {
+		v := elem.Spec().(network.LinkSpecSpec) //nolint:errcheck
+		result = append(result, v)
+	}
+
+	return result
+}

internal/app/machined/pkg/controllers/network/network.go

@@ -11,6 +11,7 @@ import (
 	networkadapter "github.com/talos-systems/talos/internal/app/machined/pkg/adapters/network"
 	talosconfig "github.com/talos-systems/talos/pkg/machinery/config"
 	"github.com/talos-systems/talos/pkg/machinery/nethelpers"
+	"github.com/talos-systems/talos/pkg/machinery/ordered"
 	"github.com/talos-systems/talos/pkg/machinery/resources/network"
 )
 
@@ -18,8 +19,11 @@ import (
 const DefaultRouteMetric = 1024
 
 // SetBondSlave sets the bond slave spec.
-func SetBondSlave(link *network.LinkSpecSpec, bondName string) {
+func SetBondSlave(link *network.LinkSpecSpec, bond ordered.Pair[string, int]) {
-	link.MasterName = bondName
+	link.BondSlave = network.BondSlave{
+		MasterName: bond.F1,
+		SlaveIndex: bond.F2,
+	}
 }
 
 // SetBondMaster sets the bond master spec.

internal/app/machined/pkg/runtime/v1alpha1/platform/equinixmetal/equinix.go

@@ -117,6 +117,8 @@ func (p *EquinixMetal) ParseMetadata(equinixMetadata *Metadata) (*runtime.Platfo
 		return nil, fmt.Errorf("error listing host interfaces: %w", err)
 	}
 
+	slaveIndex := 0
+
 	for _, iface := range equinixMetadata.Network.Interfaces {
 		if iface.Bond == "" {
 			continue
@@ -136,11 +138,15 @@ func (p *EquinixMetal) ParseMetadata(equinixMetadata *Metadata) (*runtime.Platfo
 
 				networkConfig.Links = append(networkConfig.Links,
 					network.LinkSpecSpec{
-						ConfigLayer: network.ConfigPlatform,
 						Name: hostIf.Name,
 						Up:   true,
+						BondSlave: network.BondSlave{
 							MasterName: bondName,
+							SlaveIndex: slaveIndex,
+						},
+						ConfigLayer: network.ConfigPlatform,
 					})
+				slaveIndex++
 
 				break
 			}
@@ -154,8 +160,12 @@ func (p *EquinixMetal) ParseMetadata(equinixMetadata *Metadata) (*runtime.Platfo
 					ConfigLayer: network.ConfigPlatform,
 					Name:        iface.Name,
 					Up:          true,
+					BondSlave: network.BondSlave{
 						MasterName: bondName,
+						SlaveIndex: slaveIndex,
+					},
 				})
+			slaveIndex++
 		}
 	}
 

internal/app/machined/pkg/runtime/v1alpha1/platform/equinixmetal/testdata/expected.yaml

@@ -33,6 +33,7 @@ links:
       kind: ""
       type: netrom
       masterName: bond0
+      slaveIndex: 1
       layer: platform
     - name: bond0
       logical: true

pkg/machinery/ordered/ordered.go

@@ -0,0 +1,61 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package ordered
+
+// Ordered is a constraint that permits any ordered type: any type
+// that supports the operators < <= >= >.
+type Ordered interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64 | ~string
+}
+
+// Pair is two element tuple of ordered values.
+type Pair[T1, T2 Ordered] struct {
+	F1 T1
+	F2 T2
+}
+
+// MakePair creates a new Pair.
+func MakePair[T1, T2 Ordered](v1 T1, v2 T2) Pair[T1, T2] {
+	return Pair[T1, T2]{
+		F1: v1,
+		F2: v2,
+	}
+}
+
+// Compare returns an integer comparing two pairs in natural order.
+// The result will be 0 if p == other, -1 if p < other, and +1 if p > other.
+func (p Pair[T1, T2]) Compare(other Pair[T1, T2]) int {
+	if result := cmp(p.F1, other.F1); result != 0 {
+		return result
+	}
+
+	return cmp(p.F2, other.F2)
+}
+
+// MoreThan checks if current pair is bigger than the other.
+func (p Pair[T1, T2]) MoreThan(other Pair[T1, T2]) bool {
+	return p.Compare(other) == 1
+}
+
+// LessThan checks if current pair is lesser than the other.
+func (p Pair[T1, T2]) LessThan(other Pair[T1, T2]) bool {
+	return p.Compare(other) == -1
+}
+
+// Equal checks if current pair is equal to the other.
+func (p Pair[T1, T2]) Equal(other Pair[T1, T2]) bool {
+	return p.Compare(other) == 0
+}
+
+func cmp[T Ordered](a, b T) int {
+	switch {
+	case a == b:
+		return 0
+	case a < b:
+		return -1
+	default:
+		return +1
+	}
+}

pkg/machinery/ordered/ordered_test.go

@@ -0,0 +1,46 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package ordered_test
+
+import (
+	"math"
+	"math/rand"
+	"sort"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/talos-systems/talos/pkg/machinery/ordered"
+)
+
+func TestTriple(t *testing.T) {
+	t.Parallel()
+
+	expectedSlice := []ordered.Triple[int, string, float64]{
+		ordered.MakeTriple(math.MinInt64, "Alpha", 69.0),
+		ordered.MakeTriple(-200, "Alpha", 69.0),
+		ordered.MakeTriple(-200, "Beta", -69.0),
+		ordered.MakeTriple(-200, "Beta", 69.0),
+		ordered.MakeTriple(1, "", 69.0),
+		ordered.MakeTriple(1, "Alpha", 67.0),
+		ordered.MakeTriple(1, "Alpha", 68.0),
+		ordered.MakeTriple(10, "Alpha", 68.0),
+		ordered.MakeTriple(10, "Beta", 68.0),
+		ordered.MakeTriple(math.MaxInt64, "", 69.0),
+	}
+
+	seed := time.Now().Unix()
+	rnd := rand.New(rand.NewSource(seed))
+
+	for i := 0; i < 1000; i++ {
+		a := append([]ordered.Triple[int, string, float64](nil), expectedSlice...)
+		rnd.Shuffle(len(a), func(i, j int) { a[i], a[j] = a[j], a[i] })
+		sort.Slice(a, func(i, j int) bool {
+			return a[i].LessThan(a[j])
+		})
+		require.Equal(t, expectedSlice, a, "failed with seed %d iteration %d", seed, i)
+	}
+}

pkg/machinery/ordered/triple.go

@@ -0,0 +1,48 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package ordered
+
+// Triple is three element tuple of ordered values.
+type Triple[T1, T2, T3 Ordered] struct {
+	V1 T1
+	V2 T2
+	V3 T3
+}
+
+// MakeTriple creates a new Triple.
+func MakeTriple[T1, T2, T3 Ordered](v1 T1, v2 T2, v3 T3) Triple[T1, T2, T3] {
+	return Triple[T1, T2, T3]{
+		V1: v1,
+		V2: v2,
+		V3: v3,
+	}
+}
+
+// Compare returns an integer comparing two triples in natural order.
+// The result will be 0 if t == other, -1 if t < other, and +1 if t > other.
+func (t Triple[T1, T2, T3]) Compare(other Triple[T1, T2, T3]) int {
+	if result := cmp(t.V1, other.V1); result != 0 {
+		return result
+	} else if result := cmp(t.V2, other.V2); result != 0 {
+		return result
+	}
+
+	return cmp(t.V3, other.V3)
+}
+
+// MoreThan checks if current triple is bigger than the other.
+func (t Triple[T1, T2, T3]) MoreThan(other Triple[T1, T2, T3]) bool {
+	return t.Compare(other) == 1
+}
+
+// LessThan checks if current triple is lesser than the other.
+func (t Triple[T1, T2, T3]) LessThan(other Triple[T1, T2, T3]) bool {
+	return t.Compare(other) == -1
+}
+
+// Equal checks if current triple is equal to the other.
+func (t Triple[T1, T2, T3]) Equal(other Triple[T1, T2, T3]) bool {
+	return t.Compare(other) == 0
+}

pkg/machinery/resources/network/link_spec.go

@@ -43,7 +43,7 @@ type LinkSpecSpec struct {
 	ParentName string `yaml:"parentName,omitempty"`
 
 	// MasterName indicates master link for enslaved bonded interfaces.
-	MasterName string `yaml:"masterName,omitempty"`
+	BondSlave BondSlave `yaml:",omitempty,inline"`
 
 	// These structures are present depending on "Kind" for Logical intefaces.
 	VLAN       VLANSpec       `yaml:"vlan,omitempty"`
@@ -54,6 +54,15 @@ type LinkSpecSpec struct {
 	ConfigLayer ConfigLayer `yaml:"layer"`
 }
 
+// BondSlave contains a bond's master name and slave index.
+type BondSlave struct {
+	// MasterName indicates master link for enslaved bonded interfaces.
+	MasterName string `yaml:"masterName,omitempty"`
+
+	// SlaveIndex indicates a slave's position in bond.
+	SlaveIndex int `yaml:"slaveIndex,omitempty"`
+}
+
 // DeepCopy generates a deep copy of LinkSpecSpec.
 func (spec LinkSpecSpec) DeepCopy() LinkSpecSpec {
 	cp := spec
@@ -72,51 +81,20 @@ func (spec LinkSpecSpec) DeepCopy() LinkSpecSpec {
 	return cp
 }
 
-var (
-	zeroVLAN       VLANSpec
-	zeroBondMaster BondMasterSpec
-)
-
 // Merge with other, overwriting fields from other if set.
 //
 //nolint:gocyclo
 func (spec *LinkSpecSpec) Merge(other *LinkSpecSpec) error {
 	// prefer Logical, as it is defined for bonds/vlans, etc.
-	if other.Logical {
+	updateIfNotZero(&spec.Logical, other.Logical)
-		spec.Logical = other.Logical
+	updateIfNotZero(&spec.Up, other.Up)
-	}
+	updateIfNotZero(&spec.MTU, other.MTU)
-
+	updateIfNotZero(&spec.Kind, other.Kind)
-	if other.Up {
+	updateIfNotZero(&spec.Type, other.Type)
-		spec.Up = other.Up
+	updateIfNotZero(&spec.ParentName, other.ParentName)
-	}
+	updateIfNotZero(&spec.BondSlave, other.BondSlave)
-
+	updateIfNotZero(&spec.VLAN, other.VLAN)
-	if other.MTU != 0 {
+	updateIfNotZero(&spec.BondMaster, other.BondMaster)
-		spec.MTU = other.MTU
-	}
-
-	if other.Kind != "" {
-		spec.Kind = other.Kind
-	}
-
-	if other.Type != 0 {
-		spec.Type = other.Type
-	}
-
-	if other.ParentName != "" {
-		spec.ParentName = other.ParentName
-	}
-
-	if other.MasterName != "" {
-		spec.MasterName = other.MasterName
-	}
-
-	if other.VLAN != zeroVLAN {
-		spec.VLAN = other.VLAN
-	}
-
-	if other.BondMaster != zeroBondMaster {
-		spec.BondMaster = other.BondMaster
-	}
 
 	// Wireguard config should be able to apply non-zero values in earlier config layers which may be zero values in later layers.
 	// Thus, we handle each Wireguard configuration value discretely.
@@ -133,6 +111,13 @@ func (spec *LinkSpecSpec) Merge(other *LinkSpecSpec) error {
 	return nil
 }
 
+func updateIfNotZero[T comparable](target *T, source T) {
+	var zero T
+	if source != zero {
+		*target = source
+	}
+}
+
 // NewLinkSpec initializes a LinkSpec resource.
 func NewLinkSpec(namespace resource.Namespace, id resource.ID) *LinkSpec {
 	return typed.NewResource[LinkSpecSpec, LinkSpecRD](

pkg/machinery/resources/network/link_spec_test.go

@@ -26,7 +26,10 @@ func TestLinkSpecMarshalYAML(t *testing.T) {
 		Kind:       "eth",
 		Type:       nethelpers.LinkEther,
 		ParentName: "eth1",
+		BondSlave: network.BondSlave{
 			MasterName: "bond0",
+			SlaveIndex: 0,
+		},
 		VLAN: network.VLANSpec{
 			VID:      25,
 			Protocol: nethelpers.VLANProtocol8021AD,