keyspace: add priority of tso node for the keyspace group

pkg/keyspace/tso_keyspace_group.go

@@ -173,7 +173,7 @@
 		case <-ticker.C:
 		}
 		countOfNodes := m.GetNodesCount()
-		if countOfNodes < utils.KeyspaceGroupDefaultReplicaCount {
+		if countOfNodes < utils.DefaultKeyspaceGroupReplicaCount {
 			continue
 		}
 		groups, err := m.store.LoadKeyspaceGroups(utils.DefaultKeyspaceGroupID, 0)
@@ -187,8 +187,8 @@
 		}
 		withError := false
 		for _, group := range groups {
-			if len(group.Members) < utils.KeyspaceGroupDefaultReplicaCount {
-				nodes, err := m.AllocNodesForKeyspaceGroup(group.ID, utils.KeyspaceGroupDefaultReplicaCount)
+			if len(group.Members) < utils.DefaultKeyspaceGroupReplicaCount {
+				nodes, err := m.AllocNodesForKeyspaceGroup(group.ID, utils.DefaultKeyspaceGroupReplicaCount)
 				if err != nil {
 					withError = true
 					log.Error("failed to alloc nodes for keyspace group", zap.Uint32("keyspace-group-id", group.ID), zap.Error(err))
@@ -531,7 +531,7 @@
 			return ErrKeyspaceGroupInMerging
 		}
 		// Check if the source keyspace group has enough replicas.
-		if len(splitSourceKg.Members) < utils.KeyspaceGroupDefaultReplicaCount {
+		if len(splitSourceKg.Members) < utils.DefaultKeyspaceGroupReplicaCount {
 			return ErrKeyspaceGroupNotEnoughReplicas
 		}
 		// Check if the new keyspace group already exists.
@@ -702,7 +702,10 @@
 				continue
 			}
 			exists[addr] = struct{}{}
-			nodes = append(nodes, endpoint.KeyspaceGroupMember{Address: addr})
+			nodes = append(nodes, endpoint.KeyspaceGroupMember{
+				Address:  addr,
+				Priority: utils.DefaultKeyspaceGroupReplicaPriority,
+			})
 		}
 		kg.Members = nodes
 		return m.store.SaveKeyspaceGroup(txn, kg)
@@ -737,7 +740,52 @@
 		}
 		members := make([]endpoint.KeyspaceGroupMember, 0, len(nodes))
 		for _, node := range nodes {
-			members = append(members, endpoint.KeyspaceGroupMember{Address: node})
+			members = append(members, endpoint.KeyspaceGroupMember{
+				Address:  node,
+				Priority: utils.DefaultKeyspaceGroupReplicaPriority,
+			})
+		}
+		kg.Members = members
+		return m.store.SaveKeyspaceGroup(txn, kg)
+	})
+	if err != nil {
+		return err
+	}
+	m.groups[endpoint.StringUserKind(kg.UserKind)].Put(kg)
+	return nil
+}
+
+// SetPriorityForKeyspaceGroup sets the priority of node for the keyspace group.
+func (m *GroupManager) SetPriorityForKeyspaceGroup(id uint32, node string, priority int) error {
+	m.Lock()
+	defer m.Unlock()
+	var kg *endpoint.KeyspaceGroup
+	err := m.store.RunInTxn(m.ctx, func(txn kv.Txn) error {
+		var err error
+		kg, err = m.store.LoadKeyspaceGroup(txn, id)
+		if err != nil {
+			return err
+		}
+		if kg == nil {
+			return ErrKeyspaceGroupNotExists
+		}
+		if kg.IsSplitting() {
+			return ErrKeyspaceGroupInSplit
+		}
+		if kg.IsMerging() {
+			return ErrKeyspaceGroupInMerging
+		}
+		inKeyspaceGroup := false
+		members := make([]endpoint.KeyspaceGroupMember, 0, len(kg.Members))
+		for _, member := range kg.Members {
+			if member.Address == node {
+				inKeyspaceGroup = true
+				member.Priority = priority
+			}
+			members = append(members, member)
+		}
+		if !inKeyspaceGroup {
+			return ErrNodeNotInKeyspaceGroup
 		}
 		kg.Members = members
 		return m.store.SaveKeyspaceGroup(txn, kg)

pkg/keyspace/tso_keyspace_group_test.go

@@ -244,7 +244,7 @@ func (suite *keyspaceGroupTestSuite) TestKeyspaceGroupSplit() {
 			ID:        uint32(2),
 			UserKind:  endpoint.Standard.String(),
 			Keyspaces: []uint32{111, 222, 333},
-			Members:   make([]endpoint.KeyspaceGroupMember, utils.KeyspaceGroupDefaultReplicaCount),
+			Members:   make([]endpoint.KeyspaceGroupMember, utils.DefaultKeyspaceGroupReplicaCount),
 		},
 	}
 	err := suite.kgm.CreateKeyspaceGroups(keyspaceGroups)
@@ -330,7 +330,7 @@ func (suite *keyspaceGroupTestSuite) TestKeyspaceGroupMerge() {
 			ID:        uint32(1),
 			UserKind:  endpoint.Basic.String(),
 			Keyspaces: []uint32{111, 222, 333},
-			Members:   make([]endpoint.KeyspaceGroupMember, utils.KeyspaceGroupDefaultReplicaCount),
+			Members:   make([]endpoint.KeyspaceGroupMember, utils.DefaultKeyspaceGroupReplicaCount),
 		},
 		{
 			ID:        uint32(3),

pkg/keyspace/util.go

@@ -60,6 +60,8 @@ var (
 	ErrKeyspaceGroupNotInMerging = errors.New("keyspace group is not in merging state")
 	// ErrKeyspaceNotInKeyspaceGroup is used to indicate target keyspace is not in this keyspace group.
 	ErrKeyspaceNotInKeyspaceGroup = errors.New("keyspace is not in this keyspace group")
+	// ErrNodeNotInKeyspaceGroup is used to indicate the tso node is not in this keyspace group.
+	ErrNodeNotInKeyspaceGroup = errors.New("the tso node is not in this keyspace group")
 	// ErrKeyspaceGroupNotEnoughReplicas is used to indicate not enough replicas in the keyspace group.
 	ErrKeyspaceGroupNotEnoughReplicas = errors.New("not enough replicas in the keyspace group")
 	// ErrNoAvailableNode is used to indicate no available node in the keyspace group.

pkg/mcs/utils/constant.go

@@ -72,6 +72,9 @@ const (
 	// foreseen future, and the former is just for extensibility in theory.
 	MaxKeyspaceGroupCountInUse = uint32(4096)
 
-	// KeyspaceGroupDefaultReplicaCount is the default replica count of keyspace group.
-	KeyspaceGroupDefaultReplicaCount = 2
+	// DefaultKeyspaceGroupReplicaCount is the default replica count of keyspace group.
+	DefaultKeyspaceGroupReplicaCount = 2
+
+	// DefaultKeyspaceGroupReplicaPriority is the default priority of a keyspace group replica.
+	DefaultKeyspaceGroupReplicaPriority = 100
 )

pkg/storage/endpoint/tso_keyspace_group.go

@@ -72,8 +72,12 @@ func IsUserKindValid(kind string) bool {
 }
 
 // KeyspaceGroupMember defines an election member which campaigns for the primary of the keyspace group.
+// Its `Priority` is used in keyspace group primary weighted-election to balance primaries' distribution.
+// Among multiple replicas of a keyspace group, the higher the priority, the more likely
+// the replica is to be elected as primary.
 type KeyspaceGroupMember struct {
-	Address string `json:"address"`
+	Address  string `json:"address"`
+	Priority int    `json:"priority"`
 }
 
 // SplitState defines the split state of a keyspace group.

pkg/tso/keyspace_group_manager.go

@@ -355,8 +355,11 @@
 	if !defaultKGConfigured {
 		log.Info("initializing default keyspace group")
 		group := &endpoint.KeyspaceGroup{
-			ID:        mcsutils.DefaultKeyspaceGroupID,
-			Members:   []endpoint.KeyspaceGroupMember{{Address: kgm.tsoServiceID.ServiceAddr}},
+			ID: mcsutils.DefaultKeyspaceGroupID,
+			Members: []endpoint.KeyspaceGroupMember{{
+				Address:  kgm.tsoServiceID.ServiceAddr,
+				Priority: mcsutils.DefaultKeyspaceGroupReplicaPriority,
+			}},
 			Keyspaces: []uint32{mcsutils.DefaultKeyspaceID},
 		}
 		kgm.updateKeyspaceGroup(group)
@@ -400,7 +403,10 @@
 	// If the default keyspace group isn't assigned to any tso node/pod, assign it to everyone.
 	if group.ID == mcsutils.DefaultKeyspaceGroupID && len(group.Members) == 0 {
 		// TODO: fill members with all tso nodes/pods.
-		group.Members = []endpoint.KeyspaceGroupMember{{Address: kgm.tsoServiceID.ServiceAddr}}
+		group.Members = []endpoint.KeyspaceGroupMember{{
+			Address:  kgm.tsoServiceID.ServiceAddr,
+			Priority: mcsutils.DefaultKeyspaceGroupReplicaPriority,
+		}}
 	}
 
 	if !kgm.isAssignedToMe(group) {
@@ -493,12 +499,12 @@
 	// could not be modified during the split process, so we can only check the
 	// member count of the source group here.
 	memberCount := len(sourceGroup.Members)
-	if memberCount < mcsutils.KeyspaceGroupDefaultReplicaCount {
+	if memberCount < mcsutils.DefaultKeyspaceGroupReplicaCount {
 		log.Error("the split source keyspace group does not have enough members",
 			zap.Uint32("target", targetGroup.ID),
 			zap.Uint32("source", splitSourceID),
 			zap.Int("member-count", memberCount),
-			zap.Int("replica-count", mcsutils.KeyspaceGroupDefaultReplicaCount))
+			zap.Int("replica-count", mcsutils.DefaultKeyspaceGroupReplicaCount))
 		return false
 	}
 	return true
@@ -611,8 +617,11 @@
 		log.Info("removed default keyspace group meta config from the storage. " +
 			"now every tso node/pod will initialize it")
 		group := &endpoint.KeyspaceGroup{
-			ID:        mcsutils.DefaultKeyspaceGroupID,
-			Members:   []endpoint.KeyspaceGroupMember{{Address: kgm.tsoServiceID.ServiceAddr}},
+			ID: mcsutils.DefaultKeyspaceGroupID,
+			Members: []endpoint.KeyspaceGroupMember{{
+				Address:  kgm.tsoServiceID.ServiceAddr,
+				Priority: mcsutils.DefaultKeyspaceGroupReplicaPriority,
+			}},
 			Keyspaces: []uint32{mcsutils.DefaultKeyspaceID},
 		}
 		kgm.updateKeyspaceGroup(group)

server/apiv2/handlers/tso_keyspace_group.go

@@ -23,6 +23,7 @@
 	"github.com/pkg/errors"
 	"github.com/tikv/pd/pkg/errs"
 	"github.com/tikv/pd/pkg/mcs/utils"
+	"github.com/tikv/pd/pkg/slice"
 	"github.com/tikv/pd/pkg/storage/endpoint"
 	"github.com/tikv/pd/server"
 	"github.com/tikv/pd/server/apiv2/middlewares"
@@ -40,6 +41,7 @@
 	router.DELETE("/:id", DeleteKeyspaceGroupByID)
 	router.POST("/:id/alloc", AllocNodesForKeyspaceGroup)
 	router.POST("/:id/nodes", SetNodesForKeyspaceGroup)
+	router.POST("/:id/priority", SetPriorityForKeyspaceGroup)
 	router.POST("/:id/split", SplitKeyspaceGroupByID)
 	router.DELETE("/:id/split", FinishSplitKeyspaceByID)
 	router.POST("/:id/merge", MergeKeyspaceGroups)
@@ -325,7 +327,7 @@
 		c.AbortWithStatusJSON(http.StatusBadRequest, errs.ErrBindJSON.Wrap(err).GenWithStackByCause())
 		return
 	}
-	if manager.GetNodesCount() < allocParams.Replica || allocParams.Replica < utils.KeyspaceGroupDefaultReplicaCount {
+	if manager.GetNodesCount() < allocParams.Replica || allocParams.Replica < utils.DefaultKeyspaceGroupReplicaCount {
 		c.AbortWithStatusJSON(http.StatusBadRequest, "invalid replica, should be in [2, nodes_num]")
 		return
 	}
@@ -347,7 +349,7 @@
 	c.JSON(http.StatusOK, nodes)
 }
 
-// SetNodesForKeyspaceGroupParams defines the params for setting nodes for keyspace groups.
+// SetNodesForKeyspaceGroupParams defines the params for setting nodes for keyspace group.
 // Notes: it should be used carefully.
 type SetNodesForKeyspaceGroupParams struct {
 	Nodes []string `json:"nodes"`
@@ -379,7 +381,7 @@
 		return
 	}
 	// check if nodes is less than default replica count
-	if len(setParams.Nodes) < utils.KeyspaceGroupDefaultReplicaCount {
+	if len(setParams.Nodes) < utils.DefaultKeyspaceGroupReplicaCount {
 		c.AbortWithStatusJSON(http.StatusBadRequest, "invalid num of nodes")
 		return
 	}
@@ -399,6 +401,53 @@
 	c.JSON(http.StatusOK, nil)
 }
 
+// SetPriorityForKeyspaceGroupParams defines the params for setting priority of tso node for the keyspace group.
+type SetPriorityForKeyspaceGroupParams struct {
+	Node     string `json:"node"`
+	Priority int    `json:"priority"`
+}
+
+// SetPriorityForKeyspaceGroup sets priority of tso node for the keyspace group.
+func SetPriorityForKeyspaceGroup(c *gin.Context) {
+	id, err := validateKeyspaceGroupID(c)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusBadRequest, "invalid keyspace group id")
+		return
+	}
+	svr := c.MustGet(middlewares.ServerContextKey).(*server.Server)
+	manager := svr.GetKeyspaceGroupManager()
+	if manager == nil {
+		c.AbortWithStatusJSON(http.StatusInternalServerError, groupManagerUninitializedErr)
+		return
+	}
+	setParams := &SetPriorityForKeyspaceGroupParams{}
+	err = c.BindJSON(setParams)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusBadRequest, errs.ErrBindJSON.Wrap(err).GenWithStackByCause())
+		return
+	}
+	// check if keyspace group exists
+	kg, err := manager.GetKeyspaceGroupByID(id)
+	if err != nil || kg == nil {
+		c.AbortWithStatusJSON(http.StatusBadRequest, "keyspace group does not exist")
+		return
+	}
+	// check if node exists
+	members := kg.Members
+	if slice.NoneOf(members, func(i int) bool {
+		return members[i].Address == setParams.Node
+	}) {
+		c.AbortWithStatusJSON(http.StatusBadRequest, "tso node does not exist in the keyspace group")
+	}
+	// set priority
+	err = manager.SetPriorityForKeyspaceGroup(id, setParams.Node, setParams.Priority)
+	if err != nil {
+		c.AbortWithStatusJSON(http.StatusInternalServerError, err.Error())
+		return
+	}
+	c.JSON(http.StatusOK, nil)
+}
+
 func validateKeyspaceGroupID(c *gin.Context) (uint32, error) {
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {