feat(core): split migration prep and sync pools per source node

api/core/v1alpha2/vmopcondition/condition.go

@@ -101,6 +101,10 @@ const (
 	// ReasonTargetPreparing indicates that target pod is being prepared.
 	ReasonTargetPreparing ReasonCompleted = "TargetPreparing"
 
+	// ReasonWaitingForSyncSlot indicates that the target pod is prepared but the
+	// migration is waiting for a free data-transfer (sync) slot on the source node.
+	ReasonWaitingForSyncSlot ReasonCompleted = "WaitingForSyncSlot"
+
 	// ReasonSyncing indicates that source and target are synchronizing migration data.
 	ReasonSyncing ReasonCompleted = "Syncing"
 

build/components/versions.yml

@@ -3,7 +3,7 @@ firmware:
   libvirt: v10.9.0
   edk2: stable202411
 core:
-  3p-kubevirt: v1.6.2-v12n.24
+  3p-kubevirt: feat/core/two-pool-migration
   3p-containerized-data-importer: v1.60.3-v12n.18
   distribution: 2.8.3
 package:

crds/embedded/kubevirt.yaml

@@ -636,6 +636,14 @@ spec:
                           allowed per node. Defaults to 2
                         format: int32
                         type: integer
+                      parallelSyncMigrationsPerNode:
+                        description: |-
+                          ParallelSyncMigrationsPerNode is the maximum number of concurrent outgoing live migrations
+                          per source node allowed to be in the data-transfer (sync) phase. Migrations above this cap
+                          wait in PreparingTarget with a WaitingForSyncSlot condition until a slot frees.
+                          Effective value is clamped to ParallelOutboundMigrationsPerNode. Defaults to 1.
+                        format: int32
+                        type: integer
                       progressTimeout:
                         description: |-
                           ProgressTimeout is the maximum number of seconds a live migration is allowed to make no progress.

images/hooks/pkg/hooks/migration-config/hook.go

@@ -36,18 +36,21 @@ const (
 	bandwidthPerMigrationAnnotation             = "virtualization.deckhouse.io/bandwidth-per-migration"
 	completionTimeoutPerGiBAnnotation           = "virtualization.deckhouse.io/completion-timeout-per-gib"
 	parallelOutboundMigrationsPerNodeAnnotation = "virtualization.deckhouse.io/parallel-outbound-migrations-per-node"
+	parallelSyncMigrationsPerNodeAnnotation     = "virtualization.deckhouse.io/parallel-sync-migrations-per-node"
 	progressTimeoutAnnotation                   = "virtualization.deckhouse.io/progress-timeout"
 	disableTLSAnnotation                        = "virtualization.deckhouse.io/disable-tls"
 
 	bandwidthPerMigrationValuesPath             = "virtualization.internal.virtConfig.bandwidthPerMigration"
 	completionTimeoutPerGiBValuesPath           = "virtualization.internal.virtConfig.completionTimeoutPerGiB"
 	parallelOutboundMigrationsPerNodeValuesPath = "virtualization.internal.virtConfig.parallelOutboundMigrationsPerNode"
+	parallelSyncMigrationsPerNodeValuesPath     = "virtualization.internal.virtConfig.parallelSyncMigrationsPerNode"
 	progressTimeoutValuesPath                   = "virtualization.internal.virtConfig.progressTimeout"
 	disableTLSValuesPath                        = "virtualization.internal.virtConfig.disableTLS"
 
 	defaultBandwidthPerMigration             = "640Mi"
 	defaultCompletionTimeoutPerGiB           = 800
-	defaultParallelOutboundMigrationsPerNode = 1
+	defaultParallelOutboundMigrationsPerNode = 2
+	defaultParallelSyncMigrationsPerNode     = 1
 	defaultProgressTimeout                   = 150
 	defaultDisableTLS                        = false
 )
@@ -71,6 +74,11 @@ var migrationParams = []migrationParam{
 		valuesPath:   parallelOutboundMigrationsPerNodeValuesPath,
 		defaultValue: defaultParallelOutboundMigrationsPerNode,
 	},
+	{
+		annotation:   parallelSyncMigrationsPerNodeAnnotation,
+		valuesPath:   parallelSyncMigrationsPerNodeValuesPath,
+		defaultValue: defaultParallelSyncMigrationsPerNode,
+	},
 	{
 		annotation:   progressTimeoutAnnotation,
 		valuesPath:   progressTimeoutValuesPath,

images/hooks/pkg/hooks/migration-config/hook_test.go

@@ -83,6 +83,7 @@ var _ = Describe("MigrationConfig", func() {
 			bandwidthPerMigrationAnnotation:             "1Gi",
 			completionTimeoutPerGiBAnnotation:           "1200",
 			parallelOutboundMigrationsPerNodeAnnotation: "5",
+			parallelSyncMigrationsPerNodeAnnotation:     "3",
 			progressTimeoutAnnotation:                   "300",
 			disableTLSAnnotation:                        "true",
 		}))
@@ -95,6 +96,8 @@ var _ = Describe("MigrationConfig", func() {
 				return gjson.Result{Type: gjson.Number, Num: defaultCompletionTimeoutPerGiB}
 			case parallelOutboundMigrationsPerNodeValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultParallelOutboundMigrationsPerNode}
+			case parallelSyncMigrationsPerNodeValuesPath:
+				return gjson.Result{Type: gjson.Number, Num: defaultParallelSyncMigrationsPerNode}
 			case progressTimeoutValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultProgressTimeout}
 			case disableTLSValuesPath:
@@ -113,6 +116,7 @@ var _ = Describe("MigrationConfig", func() {
 		Expect(setValues).To(HaveKeyWithValue(bandwidthPerMigrationValuesPath, "1Gi"))
 		Expect(setValues).To(HaveKeyWithValue(completionTimeoutPerGiBValuesPath, 1200))
 		Expect(setValues).To(HaveKeyWithValue(parallelOutboundMigrationsPerNodeValuesPath, 5))
+		Expect(setValues).To(HaveKeyWithValue(parallelSyncMigrationsPerNodeValuesPath, 3))
 		Expect(setValues).To(HaveKeyWithValue(progressTimeoutValuesPath, 300))
 		Expect(setValues).To(HaveKeyWithValue(disableTLSValuesPath, true))
 	})
@@ -128,6 +132,8 @@ var _ = Describe("MigrationConfig", func() {
 				return gjson.Result{Type: gjson.Number, Num: 9999}
 			case parallelOutboundMigrationsPerNodeValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: 9999}
+			case parallelSyncMigrationsPerNodeValuesPath:
+				return gjson.Result{Type: gjson.Number, Num: 9999}
 			case progressTimeoutValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: 9999}
 			case disableTLSValuesPath:
@@ -146,6 +152,7 @@ var _ = Describe("MigrationConfig", func() {
 		Expect(setValues).To(HaveKeyWithValue(bandwidthPerMigrationValuesPath, defaultBandwidthPerMigration))
 		Expect(setValues).To(HaveKeyWithValue(completionTimeoutPerGiBValuesPath, defaultCompletionTimeoutPerGiB))
 		Expect(setValues).To(HaveKeyWithValue(parallelOutboundMigrationsPerNodeValuesPath, defaultParallelOutboundMigrationsPerNode))
+		Expect(setValues).To(HaveKeyWithValue(parallelSyncMigrationsPerNodeValuesPath, defaultParallelSyncMigrationsPerNode))
 		Expect(setValues).To(HaveKeyWithValue(progressTimeoutValuesPath, defaultProgressTimeout))
 		Expect(setValues).To(HaveKeyWithValue(disableTLSValuesPath, defaultDisableTLS))
 	})
@@ -154,7 +161,8 @@ var _ = Describe("MigrationConfig", func() {
 		setSnapshots(newSnapshot(map[string]string{
 			bandwidthPerMigrationAnnotation:             defaultBandwidthPerMigration,
 			completionTimeoutPerGiBAnnotation:           "800",
-			parallelOutboundMigrationsPerNodeAnnotation: "1",
+			parallelOutboundMigrationsPerNodeAnnotation: "2",
+			parallelSyncMigrationsPerNodeAnnotation:     "1",
 			progressTimeoutAnnotation:                   "150",
 			disableTLSAnnotation:                        "false",
 		}))
@@ -167,6 +175,8 @@ var _ = Describe("MigrationConfig", func() {
 				return gjson.Result{Type: gjson.Number, Num: defaultCompletionTimeoutPerGiB}
 			case parallelOutboundMigrationsPerNodeValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultParallelOutboundMigrationsPerNode}
+			case parallelSyncMigrationsPerNodeValuesPath:
+				return gjson.Result{Type: gjson.Number, Num: defaultParallelSyncMigrationsPerNode}
 			case progressTimeoutValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultProgressTimeout}
 			case disableTLSValuesPath:
@@ -214,6 +224,8 @@ var _ = Describe("MigrationConfig", func() {
 				return gjson.Result{Type: gjson.Number, Num: defaultCompletionTimeoutPerGiB}
 			case parallelOutboundMigrationsPerNodeValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultParallelOutboundMigrationsPerNode}
+			case parallelSyncMigrationsPerNodeValuesPath:
+				return gjson.Result{Type: gjson.Number, Num: defaultParallelSyncMigrationsPerNode}
 			case progressTimeoutValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultProgressTimeout}
 			case disableTLSValuesPath:
@@ -243,6 +255,8 @@ var _ = Describe("MigrationConfig", func() {
 				return gjson.Result{Type: gjson.Number, Num: defaultCompletionTimeoutPerGiB}
 			case parallelOutboundMigrationsPerNodeValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultParallelOutboundMigrationsPerNode}
+			case parallelSyncMigrationsPerNodeValuesPath:
+				return gjson.Result{Type: gjson.Number, Num: defaultParallelSyncMigrationsPerNode}
 			case progressTimeoutValuesPath:
 				return gjson.Result{Type: gjson.Number, Num: defaultProgressTimeout}
 			case disableTLSValuesPath:

images/virt-artifact/werf.inc.yaml

@@ -9,6 +9,7 @@
 image: {{ .ModuleNamePrefix }}{{ .ImageName }}-src-artifact
 final: false
 fromImage: builder/src
+fromCacheVersion: "two-pool-migration-1"
 secrets:
 - id: SOURCE_REPO
   value: {{ $.SOURCE_REPO }}
@@ -44,6 +45,7 @@ packages:
 image: {{ .ModuleNamePrefix }}{{ .ImageName }}
 final: false
 fromImage: {{ eq $.SVACE_ENABLED "false" | ternary "builder/golang-alt-1.25" "builder/golang-alt-svace-1.25" }}
+fromCacheVersion: "two-pool-migration-1"
 mount:
 - fromPath: ~/go-pkg-cache
   to: /go/pkg

images/virt-controller/werf.inc.yaml

@@ -1,6 +1,7 @@
 ---
 image: {{ .ModuleNamePrefix }}{{ .ImageName }}
 fromImage: {{ .ModuleNamePrefix }}distroless
+fromCacheVersion: "two-pool-migration-1"
 git:
   {{- include "image mount points" . }}
 import:

images/virt-operator/werf.inc.yaml

@@ -1,6 +1,7 @@
 ---
 image: {{ .ModuleNamePrefix }}{{ .ImageName }}
 fromImage: {{ .ModuleNamePrefix }}distroless
+fromCacheVersion: "two-pool-migration-1"
 git:
   {{- include "image mount points" . }}
 import:

images/virtualization-artifact/go.mod

@@ -168,4 +168,4 @@ replace (
 )
 
 // Kubevirt API replaces
-replace kubevirt.io/api => github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260403154920-301347b413ce
+replace kubevirt.io/api => github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260417064344-ebd8172aaa7b

images/virtualization-artifact/go.sum

@@ -51,6 +51,8 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260403154920-301347b413ce h1:b6I/SUcA30j2wcOBBERbN20cKARaDAHNtSzP4XB6kgg=
 github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260403154920-301347b413ce/go.mod h1:wGZLfRa/b4w/V/hakmfcK0CmrAZGfpj+jN7BMt0s19E=
+github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260417064344-ebd8172aaa7b h1:MnsWSUYWW/xMg9b2gU5Oqi72DTG1eYSQHpioPNFW/zQ=
+github.com/deckhouse/3p-kubevirt/staging/src/kubevirt.io/api v0.0.0-20260417064344-ebd8172aaa7b/go.mod h1:wGZLfRa/b4w/V/hakmfcK0CmrAZGfpj+jN7BMt0s19E=
 github.com/deckhouse/deckhouse/pkg/log v0.0.0-20250226105106-176cd3afcdd5 h1:PsN1E0oxC/+4zdA977txrqUCuObFL3HAuu5Xnud8m8c=
 github.com/deckhouse/deckhouse/pkg/log v0.0.0-20250226105106-176cd3afcdd5/go.mod h1:Mk5HRzkc5pIcDIZ2JJ6DPuuqnwhXVkb3you8M8Mg+4w=
 github.com/distribution/reference v0.6.0 h1:0IXCQ5g4/QMHHkarYzh5l+u8T3t73zM5QvfrDyIgxBk=

images/virtualization-artifact/pkg/controller/vmop/migration/internal/handler/lifecycle.go

@@ -50,6 +50,7 @@ const (
 	progressDisksPreparing     int32 = 1
 	progressTargetScheduling   int32 = 2
 	progressTargetPreparing    int32 = 3
+	progressWaitingForSyncSlot int32 = 4
 	progressSourceSuspended    int32 = 91
 	progressTargetResumed      int32 = 92
 	progressMigrationCompleted int32 = 100
@@ -59,6 +60,7 @@ const (
 	messageSyncingSourceAndTarget = "Syncing source and target"
 	messageTargetPodScheduling    = "Target pod is being scheduled"
 	messageTargetPodPreparing     = "Target pod is being prepared"
+	messageWaitingForSyncSlot     = "Target prepared; waiting for sync slot on source node"
 	messageTargetVMResumed        = "Target VM resumed"
 	messageSourceVMSuspended      = "Source VM suspended"
 )
@@ -579,6 +581,13 @@ func (h LifecycleHandler) getInProgressReasonAndMessage(
 	case virtv1.MigrationScheduled, virtv1.MigrationPreparingTarget:
 		reason = vmopcondition.ReasonTargetPreparing
 		message = messageTargetPodPreparing
+		if cond, found := conditions.GetKVVMIMCondition(virtv1.VirtualMachineInstanceMigrationWaitingForSyncSlot, mig.Status.Conditions); found && cond.Status == corev1.ConditionTrue {
+			reason = vmopcondition.ReasonWaitingForSyncSlot
+			message = messageWaitingForSyncSlot
+			if cond.Message != "" {
+				message = cond.Message
+			}
+		}
 	case virtv1.MigrationTargetReady, virtv1.MigrationWaitingForSync, virtv1.MigrationSynchronizing, virtv1.MigrationRunning:
 		reason = vmopcondition.ReasonSyncing
 		message = messageSyncingSourceAndTarget
@@ -624,6 +633,8 @@ func (h LifecycleHandler) calculateMigrationProgress(
 		return progressTargetScheduling
 	case vmopcondition.ReasonTargetPreparing:
 		return progressTargetPreparing
+	case vmopcondition.ReasonWaitingForSyncSlot:
+		return progressWaitingForSyncSlot
 	case vmopcondition.ReasonTargetDiskError:
 		return progressTargetPreparing
 	case vmopcondition.ReasonSyncing, vmopcondition.ReasonNotConverging:

images/virtualization-artifact/pkg/livemigration/migration_configuration.go

@@ -31,6 +31,7 @@ import (
 
 const (
 	ParallelOutboundMigrationsPerNodeDefault uint32 = 2
+	ParallelSyncMigrationsPerNodeDefault     uint32 = 1
 	ParallelMigrationsPerClusterDefault      uint32 = 5
 	BandwidthPerMigrationDefault                    = "0Mi"
 	NodeDrainTaintDefaultKey                 string = "kubevirt.io/drain"
@@ -52,6 +53,13 @@ func NewMigrationConfiguration(allowAutoConverge bool, kvconfig virtv1.KubeVirt)
 	if kvconfig.Spec.Configuration.MigrationConfiguration != nil && kvconfig.Spec.Configuration.MigrationConfiguration.ParallelOutboundMigrationsPerNode != nil {
 		parallelOutboundMigrationsPerNode = *kvconfig.Spec.Configuration.MigrationConfiguration.ParallelOutboundMigrationsPerNode
 	}
+	parallelSyncMigrationsPerNode := ParallelSyncMigrationsPerNodeDefault
+	if kvconfig.Spec.Configuration.MigrationConfiguration != nil && kvconfig.Spec.Configuration.MigrationConfiguration.ParallelSyncMigrationsPerNode != nil {
+		parallelSyncMigrationsPerNode = *kvconfig.Spec.Configuration.MigrationConfiguration.ParallelSyncMigrationsPerNode
+	}
+	if parallelSyncMigrationsPerNode > parallelOutboundMigrationsPerNode {
+		parallelSyncMigrationsPerNode = parallelOutboundMigrationsPerNode
+	}
 	// Reuse default value of BandwidthPerNode as bandwidthPerMigration.
 	bandwidthPerMigration := resource.MustParse(BandwidthPerMigrationDefault)
 	if kvconfig.Spec.Configuration.MigrationConfiguration != nil && kvconfig.Spec.Configuration.MigrationConfiguration.BandwidthPerMigration != nil {
@@ -73,6 +81,7 @@ func NewMigrationConfiguration(allowAutoConverge bool, kvconfig virtv1.KubeVirt)
 	return &virtv1.MigrationConfiguration{
 		ParallelMigrationsPerCluster:      &parallelMigrationsPerCluster,
 		ParallelOutboundMigrationsPerNode: &parallelOutboundMigrationsPerNode,
+		ParallelSyncMigrationsPerNode:     &parallelSyncMigrationsPerNode,
 		NodeDrainTaintKey:                 &nodeDrainTaintDefaultKey,
 		BandwidthPerMigration:             &bandwidthPerMigration,
 		ProgressTimeout:                   &progressTimeout,

images/virtualization-artifact/pkg/livemigration/migration_configuration_test.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2026 Flant JSC
+
+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 livemigration
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"k8s.io/utils/ptr"
+	virtv1 "kubevirt.io/api/core/v1"
+)
+
+func TestNewMigrationConfiguration_ParallelSyncDefault(t *testing.T) {
+	kv := virtv1.KubeVirt{}
+	cfg := NewMigrationConfiguration(false, kv)
+
+	require.NotNil(t, cfg.ParallelOutboundMigrationsPerNode)
+	require.Equal(t, ParallelOutboundMigrationsPerNodeDefault, *cfg.ParallelOutboundMigrationsPerNode)
+	require.NotNil(t, cfg.ParallelSyncMigrationsPerNode)
+	require.Equal(t, ParallelSyncMigrationsPerNodeDefault, *cfg.ParallelSyncMigrationsPerNode)
+}
+
+func TestNewMigrationConfiguration_ParallelSyncPassthrough(t *testing.T) {
+	kv := virtv1.KubeVirt{
+		Spec: virtv1.KubeVirtSpec{
+			Configuration: virtv1.KubeVirtConfiguration{
+				MigrationConfiguration: &virtv1.MigrationConfiguration{
+					ParallelOutboundMigrationsPerNode: ptr.To[uint32](4),
+					ParallelSyncMigrationsPerNode:     ptr.To[uint32](2),
+				},
+			},
+		},
+	}
+	cfg := NewMigrationConfiguration(false, kv)
+	require.Equal(t, uint32(4), *cfg.ParallelOutboundMigrationsPerNode)
+	require.Equal(t, uint32(2), *cfg.ParallelSyncMigrationsPerNode)
+}
+
+func TestNewMigrationConfiguration_ParallelSyncClampedToOutbound(t *testing.T) {
+	kv := virtv1.KubeVirt{
+		Spec: virtv1.KubeVirtSpec{
+			Configuration: virtv1.KubeVirtConfiguration{
+				MigrationConfiguration: &virtv1.MigrationConfiguration{
+					ParallelOutboundMigrationsPerNode: ptr.To[uint32](1),
+					ParallelSyncMigrationsPerNode:     ptr.To[uint32](5),
+				},
+			},
+		},
+	}
+	cfg := NewMigrationConfiguration(false, kv)
+	require.Equal(t, uint32(1), *cfg.ParallelOutboundMigrationsPerNode)
+	require.Equal(t, uint32(1), *cfg.ParallelSyncMigrationsPerNode,
+		"sync cap must be clamped to outbound cap")
+}

openapi/values.yaml

@@ -139,6 +139,8 @@ properties:
             type: integer
           parallelOutboundMigrationsPerNode:
             type: integer
+          parallelSyncMigrationsPerNode:
+            type: integer
           progressTimeout:
             type: integer
           disableTLS:

templates/kubevirt/_kubevirt_helpers.tpl

@@ -98,6 +98,10 @@ spec:
 {{- .Values.virtualization.internal | dig "virtConfig" "parallelOutboundMigrationsPerNode" 2 -}}
 {{- end -}}
 
+{{- define "kubevirt.parallel_sync_migrations_per_node" -}}
+{{- .Values.virtualization.internal | dig "virtConfig" "parallelSyncMigrationsPerNode" 1 -}}
+{{- end -}}
+
 {{- define "kubevirt.progress_timeout" -}}
 {{- .Values.virtualization.internal | dig "virtConfig" "progressTimeout" 150 -}}
 {{- end -}}
@@ -112,5 +116,6 @@ completionTimeoutPerGiB: {{ include "kubevirt.completion_timeout_per_gib" . }}
 disableTLS: {{ include "kubevirt.disable_tls" . }}
 parallelMigrationsPerCluster: {{ include "kubevirt.parallel_migrations_per_cluster" . }}
 parallelOutboundMigrationsPerNode: {{ include "kubevirt.parallel_outbound_migrations_per_node" . }}
+parallelSyncMigrationsPerNode: {{ include "kubevirt.parallel_sync_migrations_per_node" . }}
 progressTimeout: {{ include "kubevirt.progress_timeout" . }}
 {{- end -}}