func (m *MigrateManager) CreateTask(sourceId, targetId string, ranges []topo.Range, cluster *topo.Cluster) (*MigrateTask, error) {
sourceRS := cluster.FindReplicaSetByNode(sourceId)
targetRS := cluster.FindReplicaSetByNode(targetId)
if sourceRS == nil || targetRS == nil {
return nil, ErrReplicatSetNotFound
}
task := NewMigrateTask(cluster, sourceRS, targetRS, ranges)
err := m.AddTask(task)
if err != nil {
return nil, err
}
return task, nil
}
func (m *MigrateManager) HandleNodeStateChange(cluster *topo.Cluster) {
// 如果存在迁移任务，先跳过，等结束后再处理
if len(m.tasks) > 0 {
goto done
}
// 处理主节点的迁移任务重建
for _, node := range cluster.AllNodes() {
if node.Fail {
continue
}
// Wait a while
if time.Now().Sub(m.lastTaskEndTime) < 5*time.Second {
continue
}
for id, slots := range node.Migrating {
// 根据slot生成ranges
ranges := []topo.Range{}
for _, slot := range slots {
// 如果是自己
if id == node.Id {
redis.SetSlot(node.Addr(), slot, redis.SLOT_STABLE, "")
} else {
ranges = append(ranges, topo.Range{Left: slot, Right: slot})
}
}
// Source
source := node
if !node.IsMaster() {
srs := cluster.FindReplicaSetByNode(node.Id)
if srs != nil {
source = srs.Master
}
}
// Target
rs := cluster.FindReplicaSetByNode(id)
if source.Fail || rs.Master.Fail {
continue
}
_, err := m.CreateTask(source.Id, rs.Master.Id, ranges, cluster)
if err != nil {
log.Warningf(node.Addr(), "Can not recover migrate task, %v", err)
} else {
log.Warningf(node.Addr(), "Will recover migrating task for node %s(%s) with MIGRATING info"+
", Task(Source:%s, Target:%s).", node.Id, node.Addr(), source.Addr(), rs.Master.Addr())
goto done
}
}
for id, slots := range node.Importing {
// 根据slot生成ranges
ranges := []topo.Range{}
for _, slot := range slots {
// 如果是自己
if id == node.Id {
redis.SetSlot(node.Addr(), slot, redis.SLOT_STABLE, "")
} else {
ranges = append(ranges, topo.Range{Left: slot, Right: slot})
}
}
// Target
target := node
if !node.IsMaster() {
trs := cluster.FindReplicaSetByNode(node.Id)
if trs != nil {
target = trs.Master
}
}
if target.IsStandbyMaster() {
s := cluster.FindNodeBySlot(ranges[0].Left)
if s != nil {
log.Warningf(node.Addr(), "Reset migrate task target to %s(%s)", s.Id, s.Addr())
target = s
}
}
// Source
rs := cluster.FindReplicaSetByNode(id)
if target.Fail || rs.Master.Fail {
continue
}
_, err := m.CreateTask(rs.Master.Id, target.Id, ranges, cluster)
if err != nil {
log.Warningf(node.Addr(), "Can not recover migrate task, %v", err)
} else {
log.Warningf(node.Addr(), "Will recover migrating task for node %s(%s) with IMPORTING info"+
", Task(Source:%s,Target:%s).", node.Id, node.Addr(), rs.Master.Addr(), target.Addr())
goto done
}
}
}
done:
for _, task := range m.tasks {
if task.CurrentState() != StateDone {
m.handleTaskChange(task, cluster)
}
}
}
// 更新任务状态机
func (m *MigrateManager) handleTaskChange(task *MigrateTask, cluster *topo.Cluster) error {
fromNode := cluster.FindNode(task.SourceNode().Id)
toNode := cluster.FindNode(task.TargetNode().Id)
tname := task.TaskName()
if fromNode == nil {
log.Infof(tname, "Source node %s(%s) not exist", fromNode.Addr(), fromNode.Id)
return ErrNodeNotFound
}
if toNode == nil {
log.Infof(tname, "Target node %s(%s) not exist", toNode.Addr(), toNode.Id)
return ErrNodeNotFound
}
// 角色变化说明该分片进行了主从切换
if !fromNode.IsMaster() || !toNode.IsMaster() {
log.Warningf(tname, "%s role change, cancel migration task %s\n", fromNode.Id[:6], task.TaskName())
task.SetState(StateCancelling)
return ErrSourceNodeFail
}
// 如果是源节点挂了，直接取消，等待主从切换之后重建任务
if fromNode.Fail {
log.Infof(tname, "Cancel migration task %s\n", task.TaskName())
task.SetState(StateCancelling)
return ErrSourceNodeFail
}
// 如果目标节点挂了，需要记录当前的ReplicaSet，观察等待主从切换
if toNode.Fail {
if task.CurrentState() == StateRunning {
task.SetState(StateTargetNodeFailure)
task.SetBackupReplicaSet(task.TargetReplicaSet())
return ErrTargetNodeFail
}
} else if task.CurrentState() != StateNew {
task.SetState(StateRunning)
task.SetBackupReplicaSet(nil)
}
// 如果目标节点已经进行了Failover(重新选主)，我们需要找到对应的新主
// 方法是从BackupReplicaSet里取一个从来查找
if toNode.IsStandbyMaster() {
brs := task.BackupReplicaSet()
if brs == nil {
task.SetState(StateCancelling)
log.Info(tname, "No backup replicaset found, controller maybe restarted after target master failure, can not do recovery.")
return ErrCanNotRecover
}
slaves := brs.Slaves
if len(slaves) == 0 {
task.SetState(StateCancelling)
log.Info(tname, "The dead target master has no slave, cannot do recovery.")
return ErrCanNotRecover
} else {
rs := cluster.FindReplicaSetByNode(slaves[0].Id)
if rs == nil {
task.SetState(StateCancelling)
log.Info(tname, "No replicaset for slave of dead target master found")
return ErrCanNotRecover
}
task.ReplaceTargetReplicaSet(rs)
log.Infof(tname, "Recover dead target node to %s(%s)",
rs.Master.Id, rs.Master.Addr())
}
}
return nil
}