Manage hot region label for the tikv created by auto-scaler

pkg/autoscaler/autoscaler/tidb_autoscaler.go

@@ -46,13 +46,13 @@ func (am *autoScalerManager) syncTiDB(tc *v1alpha1.TidbCluster, tac *v1alpha1.Ti
 	if targetReplicas == tc.Spec.TiDB.Replicas {
 		return nil
 	}
-	return syncTiDBAfterCalculated(tc, tac, currentReplicas, targetReplicas)
+	return syncTiDBAfterCalculated(tc, tac, currentReplicas, targetReplicas, sts)
 }
 
 // syncTiDBAfterCalculated would check the Consecutive count to avoid jitter, and it would also check the interval
 // duration between each auto-scaling. If either of them is not meet, the auto-scaling would be rejected.
 // If the auto-scaling is permitted, the timestamp would be recorded and the Consecutive count would be zeroed.
-func syncTiDBAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, currentReplicas, recommendedReplicas int32) error {
+func syncTiDBAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, currentReplicas, recommendedReplicas int32, sts *appsv1.StatefulSet) error {
 	intervalSeconds := tac.Spec.TiDB.ScaleInIntervalSeconds
 	if recommendedReplicas > currentReplicas {
 		intervalSeconds = tac.Spec.TiDB.ScaleOutIntervalSeconds
@@ -64,13 +64,14 @@ func syncTiDBAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbCluster
 	if !ableToScale {
 		return nil
 	}
-	updateTcTiDBAnnIfScale(tac)
-	tc.Spec.TiDB.Replicas = recommendedReplicas
-	return nil
+	return updateTcTiDBIfScale(tc, tac, recommendedReplicas)
 }
 
-func updateTcTiDBAnnIfScale(tac *v1alpha1.TidbClusterAutoScaler) {
+// Currently we didnt' record the auto-scaling out slot for tidb, because it is pointless for now.
+func updateTcTiDBIfScale(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, recommendedReplicas int32) error {
 	tac.Annotations[label.AnnTiDBLastAutoScalingTimestamp] = fmt.Sprintf("%d", time.Now().Unix())
+	tc.Spec.TiDB.Replicas = recommendedReplicas
+	return nil
 }
 
 func calculateTidbMetrics(tac *v1alpha1.TidbClusterAutoScaler, sts *appsv1.StatefulSet, instances []string) (int32, error) {

pkg/autoscaler/autoscaler/tikv_autoscaler.go

@@ -17,6 +17,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/pingcap/advanced-statefulset/pkg/apis/apps/v1/helper"
 	"github.com/pingcap/tidb-operator/pkg/apis/pingcap/v1alpha1"
 	"github.com/pingcap/tidb-operator/pkg/autoscaler/autoscaler/calculate"
 	"github.com/pingcap/tidb-operator/pkg/label"
@@ -46,15 +47,15 @@ func (am *autoScalerManager) syncTiKV(tc *v1alpha1.TidbCluster, tac *v1alpha1.Ti
 	if targetReplicas == tc.Spec.TiKV.Replicas {
 		return nil
 	}
-	return syncTiKVAfterCalculated(tc, tac, currentReplicas, targetReplicas)
+	return syncTiKVAfterCalculated(tc, tac, currentReplicas, targetReplicas, sts)
 }
 
 // syncTiKVAfterCalculated would check the Consecutive count to avoid jitter, and it would also check the interval
 // duration between each auto-scaling. If either of them is not meet, the auto-scaling would be rejected.
 // If the auto-scaling is permitted, the timestamp would be recorded and the Consecutive count would be zeroed.
 // The currentReplicas of TiKV calculated in auto-scaling is the count of the StateUp TiKV instance, so we need to
 // add the number of other state tikv instance replicas when we update the TidbCluster.Spec.TiKV.Replicas
-func syncTiKVAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, currentReplicas, recommendedReplicas int32) error {
+func syncTiKVAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, currentReplicas, recommendedReplicas int32, sts *appsv1.StatefulSet) error {
 
 	intervalSeconds := tac.Spec.TiKV.ScaleInIntervalSeconds
 	if recommendedReplicas > tc.Spec.TiKV.Replicas {
@@ -67,9 +68,7 @@ func syncTiKVAfterCalculated(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbCluster
 	if !ableToScale {
 		return nil
 	}
-	updateTcTiKVAnnIfScale(tac)
-	tc.Spec.TiKV.Replicas = recommendedReplicas
-	return nil
+	return updateTcTiKVIfScale(tc, tac, currentReplicas, recommendedReplicas, sts)
 }
 
 //TODO: fetch tikv instances info from pdapi in future
@@ -83,8 +82,25 @@ func filterTiKVInstances(tc *v1alpha1.TidbCluster) []string {
 	return instances
 }
 
-func updateTcTiKVAnnIfScale(tac *v1alpha1.TidbClusterAutoScaler) {
+// we record the auto-scaling out slot for tikv, in order to add special hot labels when they are created
+func updateTcTiKVIfScale(tc *v1alpha1.TidbCluster, tac *v1alpha1.TidbClusterAutoScaler, currentReplicas, recommendedReplicas int32, sts *appsv1.StatefulSet) error {
 	tac.Annotations[label.AnnTiKVLastAutoScalingTimestamp] = fmt.Sprintf("%d", time.Now().Unix())
+	if recommendedReplicas > currentReplicas {
+		newlyScaleOutOrdinalSets := helper.GetPodOrdinals(recommendedReplicas, sts).Difference(helper.GetPodOrdinals(currentReplicas, sts))
+		if newlyScaleOutOrdinalSets.Len() > 0 {
+			if tc.Annotations == nil {
+				tc.Annotations = map[string]string{}
+			}
+			existed := operatorUtils.GetAutoScalingOutSlots(tc, v1alpha1.TiKVMemberType)
+			v, err := operatorUtils.Encode(newlyScaleOutOrdinalSets.Union(existed).List())
+			if err != nil {
+				return err
+			}
+			tc.Annotations[label.AnnTiKVAutoScalingOutOrdinals] = v
+		}
+	}
+	tc.Spec.TiKV.Replicas = recommendedReplicas
+	return nil
 }
 
 func calculateTikvMetrics(tac *v1alpha1.TidbClusterAutoScaler, sts *appsv1.StatefulSet, instances []string) (int32, error) {

pkg/label/label.go

@@ -114,6 +114,10 @@ const (
 	AnnAutoScalingTargetName = "auto-scaling.tidb.pingcap.com/target-name"
 	// AnnAutoScalingTargetNamespace describes the target TidbCluster Ref Namespace for the TidbCluserAutoScaler
 	AnnAutoScalingTargetNamespace = "auto-scaling.tidb.pingcap.com/target-namespace"
+	// AnnTiKVAutoScalingOutOrdinals describe the tikv pods' ordinal list which is created by auto-scaling out
+	AnnTiKVAutoScalingOutOrdinals = "tikv.tidb.pingcap.com/scale-out-ordinals"
+	// AnnTiDBAutoScalingOutOrdinals describe the tidb pods' ordinal list which is created by auto-scaling out
+	AnnTiDBAutoScalingOutOrdinals = "tidb.tidb.pingcap.com/scale-out-ordinals"
 
 	// PDLabelVal is PD label value
 	PDLabelVal string = "pd"

pkg/manager/member/pd_scaler.go

@@ -47,7 +47,7 @@ func (psd *pdScaler) Scale(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSet, n
 	} else if scaling < 0 {
 		return psd.ScaleIn(tc, oldSet, newSet)
 	}
-	return nil
+	return psd.SyncAutoScalerAnn(tc, oldSet)
 }
 
 func (psd *pdScaler) ScaleOut(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSet, newSet *apps.StatefulSet) error {
@@ -167,6 +167,10 @@ func (psd *pdScaler) ScaleIn(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSet,
 	return nil
 }
 
+func (psd *pdScaler) SyncAutoScalerAnn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet) error {
+	return nil
+}
+
 type fakePDScaler struct{}
 
 // NewFakePDScaler returns a fake Scaler
@@ -192,3 +196,7 @@ func (fsd *fakePDScaler) ScaleIn(_ *v1alpha1.TidbCluster, oldSet *apps.StatefulS
 	setReplicasAndDeleteSlots(newSet, *oldSet.Spec.Replicas-1, nil)
 	return nil
 }
+
+func (fsd *fakePDScaler) SyncAutoScalerAnn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet) error {
+	return nil
+}

pkg/manager/member/scaler.go

@@ -35,6 +35,13 @@ const (
 	skipReasonScalerAnnDeferDeletingIsEmpty = "scaler: pvc annotations defer deleting is empty"
 )
 
+// TODO: add document to explain the hot region label
+var (
+	hostRegionLabel = map[string]string{
+		"specialUse": "hotRegion",
+	}
+)
+
 // Scaler implements the logic for scaling out or scaling in the cluster.
 type Scaler interface {
 	// Scale scales the cluster. It does nothing if scaling is not needed.
@@ -43,6 +50,8 @@ type Scaler interface {
 	ScaleOut(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet, desired *apps.StatefulSet) error
 	// ScaleIn scales in the cluster
 	ScaleIn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet, desired *apps.StatefulSet) error
+	// SyncAutoScalerAnn would sync Ann created by AutoScaler
+	SyncAutoScalerAnn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet) error
 }
 
 type generalScaler struct {

pkg/manager/member/tikv_scaler.go

@@ -18,10 +18,12 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/pingcap/advanced-statefulset/pkg/apis/apps/v1/helper"
 	"github.com/pingcap/tidb-operator/pkg/apis/pingcap/v1alpha1"
 	"github.com/pingcap/tidb-operator/pkg/controller"
 	"github.com/pingcap/tidb-operator/pkg/label"
 	"github.com/pingcap/tidb-operator/pkg/pdapi"
+	"github.com/pingcap/tidb-operator/pkg/util"
 	apps "k8s.io/api/apps/v1"
 	corelisters "k8s.io/client-go/listers/core/v1"
 	glog "k8s.io/klog"
@@ -48,7 +50,8 @@ func (tsd *tikvScaler) Scale(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSet,
 	} else if scaling < 0 {
 		return tsd.ScaleIn(tc, oldSet, newSet)
 	}
-	return nil
+	// we only sync auto scaler annotations when we are finishing syncing scaling
+	return tsd.SyncAutoScalerAnn(tc, oldSet)
 }
 
 func (tsd *tikvScaler) ScaleOut(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSet, newSet *apps.StatefulSet) error {
@@ -190,6 +193,55 @@ func (tsd *tikvScaler) ScaleIn(tc *v1alpha1.TidbCluster, oldSet *apps.StatefulSe
 	return fmt.Errorf("TiKV %s/%s not found in cluster", ns, podName)
 }
 
+// SyncAutoScalerAnn would reclaim the auto-scaling out slots if the target pod is no longer existed
+// For the auto-scaling slots, we would add the special hot region label to the store with pdapi.
+func (tsd *tikvScaler) SyncAutoScalerAnn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet) error {
+	currentScalingSlots := util.GetAutoScalingOutSlots(tc, v1alpha1.TiKVMemberType)
+	if currentScalingSlots.Len() < 1 {
+		return nil
+	}
+	currentOrdinals := helper.GetPodOrdinals(tc.Spec.TiKV.Replicas, actual)
+
+	// reclaim the auto-scaling out slots if the target pod is no longer existed
+	if !currentOrdinals.HasAll(currentScalingSlots.List()...) {
+		reclaimedSlots := currentScalingSlots.Difference(currentOrdinals)
+		currentScalingSlots = currentScalingSlots.Delete(reclaimedSlots.List()...)
+		if currentScalingSlots.Len() < 1 {
+			delete(tc.Annotations, label.AnnTiKVAutoScalingOutOrdinals)
+			return nil
+		}
+		v, err := util.Encode(currentScalingSlots.List())
+		if err != nil {
+			return err
+		}
+		tc.Annotations[label.AnnTiKVAutoScalingOutOrdinals] = v
+		return nil
+	}
+
+	// For the auto-scaling slots, we would add the special hot region label to the store with pdapi.
+	pdClient := tsd.pdControl.GetPDClient(pdapi.Namespace(tc.Namespace), tc.Name, *tc.Spec.EnableTLSCluster)
+	for k := range currentScalingSlots {
+		podName := util.GetPodName(tc, v1alpha1.TiKVMemberType, k)
+		for _, store := range tc.Status.TiKV.Stores {
+			if store.PodName == podName {
+				id, err := strconv.ParseUint(store.ID, 10, 64)
+				if err != nil {
+					return err
+				}
+				ok, err := pdClient.SetStoreLabels(id, hostRegionLabel)
+				if err != nil {
+					return err
+				}
+				if !ok {
+					return fmt.Errorf("tc[%s/%s]'s pod[%s] failed to add special hot region label", tc.Namespace, tc.Name, podName)
+				}
+				break
+			}
+		}
+	}
+	return nil
+}
+
 type fakeTiKVScaler struct{}
 
 // NewFakeTiKVScaler returns a fake tikv Scaler
@@ -215,3 +267,7 @@ func (fsd *fakeTiKVScaler) ScaleIn(_ *v1alpha1.TidbCluster, oldSet *apps.Statefu
 	setReplicasAndDeleteSlots(newSet, *oldSet.Spec.Replicas-1, nil)
 	return nil
 }
+
+func (fsd *fakeTiKVScaler) SyncAutoScalerAnn(tc *v1alpha1.TidbCluster, actual *apps.StatefulSet) error {
+	return nil
+}

pkg/manager/member/utils.go

@@ -24,6 +24,7 @@ import (
 	"github.com/pingcap/tidb-operator/pkg/apis/pingcap/v1alpha1"
 	"github.com/pingcap/tidb-operator/pkg/controller"
 	"github.com/pingcap/tidb-operator/pkg/label"
+	"github.com/pingcap/tidb-operator/pkg/util"
 	apps "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
@@ -71,7 +72,7 @@ func statefulSetIsUpgrading(set *apps.StatefulSet) bool {
 
 // SetStatefulSetLastAppliedConfigAnnotation set last applied config to Statefulset's annotation
 func SetStatefulSetLastAppliedConfigAnnotation(set *apps.StatefulSet) error {
-	setApply, err := encode(set.Spec)
+	setApply, err := util.Encode(set.Spec)
 	if err != nil {
 		return err
 	}
@@ -97,14 +98,6 @@ func GetLastAppliedConfig(set *apps.StatefulSet) (*apps.StatefulSetSpec, *corev1
 	return spec, &spec.Template.Spec, nil
 }
 
-func encode(obj interface{}) (string, error) {
-	b, err := json.Marshal(obj)
-	if err != nil {
-		return "", err
-	}
-	return string(b), nil
-}
-
 // statefulSetEqual compares the new Statefulset's spec with old Statefulset's last applied config
 func statefulSetEqual(new apps.StatefulSet, old apps.StatefulSet) bool {
 	if !apiequality.Semantic.DeepEqual(new.Annotations, old.Annotations) {

pkg/util/util.go

@@ -126,3 +126,40 @@ func IsStatefulSetScaling(set *appsv1.StatefulSet) bool {
 func GetStatefulSetName(tc *v1alpha1.TidbCluster, memberType v1alpha1.MemberType) string {
 	return fmt.Sprintf("%s-%s", tc.Name, memberType.String())
 }
+
+func GetAutoScalingOutSlots(tc *v1alpha1.TidbCluster, memberType v1alpha1.MemberType) sets.Int32 {
+	s := sets.Int32{}
+	l := ""
+	switch memberType {
+	case v1alpha1.PDMemberType:
+		return s
+	case v1alpha1.TiKVMemberType:
+		l = label.AnnTiKVAutoScalingOutOrdinals
+	case v1alpha1.TiDBMemberType:
+		l = label.AnnTiDBAutoScalingOutOrdinals
+	default:
+		return s
+	}
+	if tc.Annotations == nil {
+		return s
+	}
+	v, existed := tc.Annotations[l]
+	if !existed {
+		return s
+	}
+	var slice []int32
+	err := json.Unmarshal([]byte(v), &slice)
+	if err != nil {
+		return s
+	}
+	s.Insert(slice...)
+	return s
+}
+
+func Encode(obj interface{}) (string, error) {
+	b, err := json.Marshal(obj)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}