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package shell
import ( "flag" "fmt" "github.com/chrislusf/seaweedfs/weed/storage/super_block" "github.com/chrislusf/seaweedfs/weed/storage/types" "io" "os" "sort" "time"
"github.com/chrislusf/seaweedfs/weed/pb/master_pb" "github.com/chrislusf/seaweedfs/weed/storage/needle" )
func init() { Commands = append(Commands, &commandVolumeBalance{}) }
type commandVolumeBalance struct { }
func (c *commandVolumeBalance) Name() string { return "volume.balance" }
func (c *commandVolumeBalance) Help() string { return `balance all volumes among volume servers
volume.balance [-collection ALL|EACH_COLLECTION|<collection_name>] [-force] [-dataCenter=<data_center_name>]
Algorithm:
For each type of volume server (different max volume count limit){ for each collection { balanceWritableVolumes() balanceReadOnlyVolumes() } }
func balanceWritableVolumes(){ idealWritableVolumeRatio = totalWritableVolumes / totalNumberOfMaxVolumes for hasMovedOneVolume { sort all volume servers ordered by the localWritableVolumeRatio = localWritableVolumes to localVolumeMax pick the volume server B with the highest localWritableVolumeRatio y for any the volume server A with the number of writable volumes x + 1 <= idealWritableVolumeRatio * localVolumeMax { if y > localWritableVolumeRatio { if B has a writable volume id v that A does not have, and satisfy v replication requirements { move writable volume v from A to B } } } } } func balanceReadOnlyVolumes(){ //similar to balanceWritableVolumes
}
` }
func (c *commandVolumeBalance) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {
if err = commandEnv.confirmIsLocked(); err != nil { return }
balanceCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError) collection := balanceCommand.String("collection", "EACH_COLLECTION", "collection name, or use \"ALL_COLLECTIONS\" across collections, \"EACH_COLLECTION\" for each collection") dc := balanceCommand.String("dataCenter", "", "only apply the balancing for this dataCenter") applyBalancing := balanceCommand.Bool("force", false, "apply the balancing plan.") if err = balanceCommand.Parse(args); err != nil { return nil }
// collect topology information
topologyInfo, volumeSizeLimitMb, err := collectTopologyInfo(commandEnv) if err != nil { return err }
volumeServers := collectVolumeServersByDc(topologyInfo, *dc) volumeReplicas, _ := collectVolumeReplicaLocations(topologyInfo) diskTypes := collectVolumeDiskTypes(topologyInfo)
if *collection == "EACH_COLLECTION" { collections, err := ListCollectionNames(commandEnv, true, false) if err != nil { return err } for _, c := range collections { if err = balanceVolumeServers(commandEnv, diskTypes, volumeReplicas, volumeServers, volumeSizeLimitMb*1024*1024, c, *applyBalancing); err != nil { return err } } } else if *collection == "ALL_COLLECTIONS" { if err = balanceVolumeServers(commandEnv, diskTypes, volumeReplicas, volumeServers, volumeSizeLimitMb*1024*1024, "ALL_COLLECTIONS", *applyBalancing); err != nil { return err } } else { if err = balanceVolumeServers(commandEnv, diskTypes, volumeReplicas, volumeServers, volumeSizeLimitMb*1024*1024, *collection, *applyBalancing); err != nil { return err } }
return nil }
func balanceVolumeServers(commandEnv *CommandEnv, diskTypes []types.DiskType, volumeReplicas map[uint32][]*VolumeReplica, nodes []*Node, volumeSizeLimit uint64, collection string, applyBalancing bool) error {
for _, diskType := range diskTypes { if err := balanceVolumeServersByDiskType(commandEnv, diskType, volumeReplicas, nodes, volumeSizeLimit, collection, applyBalancing); err != nil { return err } } return nil
}
func balanceVolumeServersByDiskType(commandEnv *CommandEnv, diskType types.DiskType, volumeReplicas map[uint32][]*VolumeReplica, nodes []*Node, volumeSizeLimit uint64, collection string, applyBalancing bool) error {
// balance read only volumes
for _, n := range nodes { n.selectVolumes(func(v *master_pb.VolumeInformationMessage) bool { if collection != "ALL_COLLECTIONS" { if v.Collection != collection { return false } } return v.DiskType == string(diskType) && (v.ReadOnly || v.Size >= volumeSizeLimit) }) } if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortReadOnlyVolumes, applyBalancing); err != nil { return err }
// balance writable volumes
for _, n := range nodes { n.selectVolumes(func(v *master_pb.VolumeInformationMessage) bool { if collection != "ALL_COLLECTIONS" { if v.Collection != collection { return false } } return v.DiskType == string(diskType) && (!v.ReadOnly && v.Size < volumeSizeLimit) }) } if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortWritableVolumes, applyBalancing); err != nil { return err }
return nil }
func collectVolumeServersByDc(t *master_pb.TopologyInfo, selectedDataCenter string) (nodes []*Node) { for _, dc := range t.DataCenterInfos { if selectedDataCenter != "" && dc.Id != selectedDataCenter { continue } for _, r := range dc.RackInfos { for _, dn := range r.DataNodeInfos { nodes = append(nodes, &Node{ info: dn, dc: dc.Id, rack: r.Id, }) } } } return }
func collectVolumeDiskTypes(t *master_pb.TopologyInfo) (diskTypes []types.DiskType) { knownTypes := make(map[string]bool) for _, dc := range t.DataCenterInfos { for _, r := range dc.RackInfos { for _, dn := range r.DataNodeInfos { for diskType, _ := range dn.DiskInfos { if _, found := knownTypes[diskType]; !found { knownTypes[diskType] = true } } } } } for diskType, _ := range knownTypes { diskTypes = append(diskTypes, types.ToDiskType(diskType)) } return }
type Node struct { info *master_pb.DataNodeInfo selectedVolumes map[uint32]*master_pb.VolumeInformationMessage dc string rack string }
type CapacityFunc func(*master_pb.DataNodeInfo) int
func capacityByMaxVolumeCount(diskType types.DiskType) CapacityFunc { return func(info *master_pb.DataNodeInfo) int { diskInfo, found := info.DiskInfos[string(diskType)] if !found { return 0 } return int(diskInfo.MaxVolumeCount) } }
func capacityByFreeVolumeCount(diskType types.DiskType) CapacityFunc { return func(info *master_pb.DataNodeInfo) int { diskInfo, found := info.DiskInfos[string(diskType)] if !found { return 0 } return int(diskInfo.MaxVolumeCount - diskInfo.VolumeCount) } }
func (n *Node) localVolumeRatio(capacityFunc CapacityFunc) float64 { return divide(len(n.selectedVolumes), capacityFunc(n.info)) }
func (n *Node) localVolumeNextRatio(capacityFunc CapacityFunc) float64 { return divide(len(n.selectedVolumes)+1, capacityFunc(n.info)) }
func (n *Node) selectVolumes(fn func(v *master_pb.VolumeInformationMessage) bool) { n.selectedVolumes = make(map[uint32]*master_pb.VolumeInformationMessage) for _, diskInfo := range n.info.DiskInfos { for _, v := range diskInfo.VolumeInfos { if fn(v) { n.selectedVolumes[v.Id] = v } } } }
func sortWritableVolumes(volumes []*master_pb.VolumeInformationMessage) { sort.Slice(volumes, func(i, j int) bool { return volumes[i].Size < volumes[j].Size }) }
func sortReadOnlyVolumes(volumes []*master_pb.VolumeInformationMessage) { sort.Slice(volumes, func(i, j int) bool { return volumes[i].Id < volumes[j].Id }) }
func balanceSelectedVolume(commandEnv *CommandEnv, volumeReplicas map[uint32][]*VolumeReplica, nodes []*Node, capacityFunc CapacityFunc, sortCandidatesFn func(volumes []*master_pb.VolumeInformationMessage), applyBalancing bool) (err error) { selectedVolumeCount, volumeMaxCount := 0, 0 var nodesWithCapacity []*Node for _, dn := range nodes { selectedVolumeCount += len(dn.selectedVolumes) capacity := capacityFunc(dn.info) if capacity > 0 { nodesWithCapacity = append(nodesWithCapacity, dn) } volumeMaxCount += capacity }
idealVolumeRatio := divide(selectedVolumeCount, volumeMaxCount)
hasMoved := true
// fmt.Fprintf(os.Stdout, " total %d volumes, max %d volumes, idealVolumeRatio %f\n", selectedVolumeCount, volumeMaxCount, idealVolumeRatio)
for hasMoved { hasMoved = false sort.Slice(nodesWithCapacity, func(i, j int) bool { return nodesWithCapacity[i].localVolumeRatio(capacityFunc) < nodesWithCapacity[j].localVolumeRatio(capacityFunc) })
fullNode := nodesWithCapacity[len(nodesWithCapacity)-1] var candidateVolumes []*master_pb.VolumeInformationMessage for _, v := range fullNode.selectedVolumes { candidateVolumes = append(candidateVolumes, v) } sortCandidatesFn(candidateVolumes)
for i := 0; i < len(nodesWithCapacity)-1; i++ { emptyNode := nodesWithCapacity[i] if !(fullNode.localVolumeRatio(capacityFunc) > idealVolumeRatio && emptyNode.localVolumeNextRatio(capacityFunc) <= idealVolumeRatio) { // no more volume servers with empty slots
break } hasMoved, err = attemptToMoveOneVolume(commandEnv, volumeReplicas, fullNode, candidateVolumes, emptyNode, applyBalancing) if err != nil { return } if hasMoved { // moved one volume
break } } } return nil }
func attemptToMoveOneVolume(commandEnv *CommandEnv, volumeReplicas map[uint32][]*VolumeReplica, fullNode *Node, candidateVolumes []*master_pb.VolumeInformationMessage, emptyNode *Node, applyBalancing bool) (hasMoved bool, err error) {
for _, v := range candidateVolumes { hasMoved, err = maybeMoveOneVolume(commandEnv, volumeReplicas, fullNode, v, emptyNode, applyBalancing) if err != nil { return } if hasMoved { break } } return }
func maybeMoveOneVolume(commandEnv *CommandEnv, volumeReplicas map[uint32][]*VolumeReplica, fullNode *Node, candidateVolume *master_pb.VolumeInformationMessage, emptyNode *Node, applyChange bool) (hasMoved bool, err error) {
if candidateVolume.ReplicaPlacement > 0 { replicaPlacement, _ := super_block.NewReplicaPlacementFromByte(byte(candidateVolume.ReplicaPlacement)) if !isGoodMove(replicaPlacement, volumeReplicas[candidateVolume.Id], fullNode, emptyNode) { return false, nil } } if _, found := emptyNode.selectedVolumes[candidateVolume.Id]; !found { if err = moveVolume(commandEnv, candidateVolume, fullNode, emptyNode, applyChange); err == nil { adjustAfterMove(candidateVolume, volumeReplicas, fullNode, emptyNode) return true, nil } else { return } } return }
func moveVolume(commandEnv *CommandEnv, v *master_pb.VolumeInformationMessage, fullNode *Node, emptyNode *Node, applyChange bool) error { collectionPrefix := v.Collection + "_" if v.Collection == "" { collectionPrefix = "" } fmt.Fprintf(os.Stdout, " moving %s volume %s%d %s => %s\n", v.DiskType, collectionPrefix, v.Id, fullNode.info.Id, emptyNode.info.Id) if applyChange { return LiveMoveVolume(commandEnv.option.GrpcDialOption, os.Stderr, needle.VolumeId(v.Id), fullNode.info.Id, emptyNode.info.Id, 5*time.Second, v.DiskType, false) } return nil }
func isGoodMove(placement *super_block.ReplicaPlacement, existingReplicas []*VolumeReplica, sourceNode, targetNode *Node) bool { for _, replica := range existingReplicas { if replica.location.dataNode.Id == targetNode.info.Id && replica.location.rack == targetNode.rack && replica.location.dc == targetNode.dc { // never move to existing nodes
return false } } dcs, racks := make(map[string]bool), make(map[string]int) for _, replica := range existingReplicas { if replica.location.dataNode.Id != sourceNode.info.Id { dcs[replica.location.DataCenter()] = true racks[replica.location.Rack()]++ } }
dcs[targetNode.dc] = true racks[fmt.Sprintf("%s %s", targetNode.dc, targetNode.rack)]++
if len(dcs) != placement.DiffDataCenterCount+1 { return false }
if len(racks) != placement.DiffRackCount+placement.DiffDataCenterCount+1 { return false }
for _, sameRackCount := range racks { if sameRackCount != placement.SameRackCount+1 { return false } }
return true
}
func adjustAfterMove(v *master_pb.VolumeInformationMessage, volumeReplicas map[uint32][]*VolumeReplica, fullNode *Node, emptyNode *Node) { delete(fullNode.selectedVolumes, v.Id) if emptyNode.selectedVolumes != nil { emptyNode.selectedVolumes[v.Id] = v } existingReplicas := volumeReplicas[v.Id] for _, replica := range existingReplicas { if replica.location.dataNode.Id == fullNode.info.Id && replica.location.rack == fullNode.rack && replica.location.dc == fullNode.dc { loc := newLocation(emptyNode.dc, emptyNode.rack, emptyNode.info) replica.location = &loc return } } }
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