seaweedfs/weed/shell/command_volume_fix_replication.go

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package shell
import (
"context"
"fmt"
"github.com/chrislusf/seaweedfs/weed/storage/needle"
"io"
"sort"
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"github.com/chrislusf/seaweedfs/weed/operation"
"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
"github.com/chrislusf/seaweedfs/weed/storage/super_block"
)
func init() {
Commands = append(Commands, &commandVolumeFixReplication{})
}
type commandVolumeFixReplication struct {
}
func (c *commandVolumeFixReplication) Name() string {
return "volume.fix.replication"
}
func (c *commandVolumeFixReplication) Help() string {
return `add replicas to volumes that are missing replicas
This command finds all over-replicated volumes. If found, it will purge the oldest copies and stop.
This command also finds all under-replicated volumes, and finds volume servers with free slots.
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If the free slots satisfy the replication requirement, the volume content is copied over and mounted.
volume.fix.replication -n # do not take action
volume.fix.replication # actually deleting or copying the volume files and mount the volume
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Note:
* each time this will only add back one replica for one volume id. If there are multiple replicas
are missing, e.g. multiple volume servers are new, you may need to run this multiple times.
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* do not run this too quickly within seconds, since the new volume replica may take a few seconds
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to register itself to the master.
`
}
func (c *commandVolumeFixReplication) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {
if err = commandEnv.confirmIsLocked(); err != nil {
return
}
takeAction := true
if len(args) > 0 && args[0] == "-n" {
takeAction = false
}
var resp *master_pb.VolumeListResponse
err = commandEnv.MasterClient.WithClient(func(client master_pb.SeaweedClient) error {
resp, err = client.VolumeList(context.Background(), &master_pb.VolumeListRequest{})
return err
})
if err != nil {
return err
}
// find all volumes that needs replication
// collect all data nodes
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volumeReplicas := make(map[uint32][]*VolumeReplica)
var allLocations []location
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eachDataNode(resp.TopologyInfo, func(dc string, rack RackId, dn *master_pb.DataNodeInfo) {
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loc := newLocation(dc, string(rack), dn)
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for _, v := range dn.VolumeInfos {
volumeReplicas[v.Id] = append(volumeReplicas[v.Id], &VolumeReplica{
location: &loc,
info: v,
})
}
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allLocations = append(allLocations, loc)
})
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if len(allLocations) == 0 {
return fmt.Errorf("no data nodes at all")
}
// find all under replicated volumes
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var underReplicatedVolumeIds, overReplicatedVolumeIds []uint32
for vid, replicas := range volumeReplicas {
replica := replicas[0]
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replicaPlacement, _ := super_block.NewReplicaPlacementFromByte(byte(replica.info.ReplicaPlacement))
if replicaPlacement.GetCopyCount() > len(replicas) {
underReplicatedVolumeIds = append(underReplicatedVolumeIds, vid)
} else if replicaPlacement.GetCopyCount() < len(replicas) {
overReplicatedVolumeIds = append(overReplicatedVolumeIds, vid)
fmt.Fprintf(writer, "volume %d replication %s, but over replicated %+d\n", replica.info.Id, replicaPlacement, len(replicas))
}
}
if len(overReplicatedVolumeIds) > 0 {
return c.fixOverReplicatedVolumes(commandEnv, writer, takeAction, overReplicatedVolumeIds, volumeReplicas, allLocations)
}
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if len(underReplicatedVolumeIds) == 0 {
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return nil
}
// find the most under populated data nodes
keepDataNodesSorted(allLocations)
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return c.fixUnderReplicatedVolumes(commandEnv, writer, takeAction, underReplicatedVolumeIds, volumeReplicas, allLocations)
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}
func (c *commandVolumeFixReplication) fixOverReplicatedVolumes(commandEnv *CommandEnv, writer io.Writer, takeAction bool, overReplicatedVolumeIds []uint32, volumeReplicas map[uint32][]*VolumeReplica, allLocations []location) error {
for _, vid := range overReplicatedVolumeIds {
replicas := volumeReplicas[vid]
replicaPlacement, _ := super_block.NewReplicaPlacementFromByte(byte(replicas[0].info.ReplicaPlacement))
replica := pickOneReplicaToDelete(replicas, replicaPlacement)
fmt.Fprintf(writer, "deleting volume %d from %s ...\n", replica.info.Id, replica.location.dataNode.Id)
if !takeAction {
break
}
if err := deleteVolume(commandEnv.option.GrpcDialOption, needle.VolumeId(replica.info.Id), replica.location.dataNode.Id); err != nil {
return fmt.Errorf("deleting volume %d from %s : %v", replica.info.Id, replica.location.dataNode.Id, err)
}
}
return nil
}
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func (c *commandVolumeFixReplication) fixUnderReplicatedVolumes(commandEnv *CommandEnv, writer io.Writer, takeAction bool, underReplicatedVolumeIds []uint32, volumeReplicas map[uint32][]*VolumeReplica, allLocations []location) error {
for _, vid := range underReplicatedVolumeIds {
replicas := volumeReplicas[vid]
replica := pickOneReplicaToCopyFrom(replicas)
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replicaPlacement, _ := super_block.NewReplicaPlacementFromByte(byte(replica.info.ReplicaPlacement))
foundNewLocation := false
for _, dst := range allLocations {
// check whether data nodes satisfy the constraints
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if dst.dataNode.FreeVolumeCount > 0 && satisfyReplicaPlacement(replicaPlacement, replicas, dst) {
// ask the volume server to replicate the volume
foundNewLocation = true
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fmt.Fprintf(writer, "replicating volume %d %s from %s to dataNode %s ...\n", replica.info.Id, replicaPlacement, replica.location.dataNode.Id, dst.dataNode.Id)
if !takeAction {
break
}
err := operation.WithVolumeServerClient(dst.dataNode.Id, commandEnv.option.GrpcDialOption, func(volumeServerClient volume_server_pb.VolumeServerClient) error {
_, replicateErr := volumeServerClient.VolumeCopy(context.Background(), &volume_server_pb.VolumeCopyRequest{
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VolumeId: replica.info.Id,
SourceDataNode: replica.location.dataNode.Id,
})
if replicateErr != nil {
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return fmt.Errorf("copying from %s => %s : %v", replica.location.dataNode.Id, dst.dataNode.Id, replicateErr)
}
return nil
})
if err != nil {
return err
}
// adjust free volume count
dst.dataNode.FreeVolumeCount--
keepDataNodesSorted(allLocations)
break
}
}
if !foundNewLocation {
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fmt.Fprintf(writer, "failed to place volume %d replica as %s, existing:%+v\n", replica.info.Id, replicaPlacement, len(replicas))
}
}
return nil
}
func keepDataNodesSorted(dataNodes []location) {
sort.Slice(dataNodes, func(i, j int) bool {
return dataNodes[i].dataNode.FreeVolumeCount > dataNodes[j].dataNode.FreeVolumeCount
})
}
/*
if on an existing data node {
return false
}
if different from existing dcs {
if lack on different dcs {
return true
}else{
return false
}
}
if not on primary dc {
return false
}
if different from existing racks {
if lack on different racks {
return true
}else{
return false
}
}
if not on primary rack {
return false
}
if lacks on same rack {
return true
} else {
return false
}
*/
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func satisfyReplicaPlacement(replicaPlacement *super_block.ReplicaPlacement, replicas []*VolumeReplica, possibleLocation location) bool {
existingDataCenters, _, existingDataNodes := countReplicas(replicas)
if _, found := existingDataNodes[possibleLocation.String()]; found {
// avoid duplicated volume on the same data node
return false
}
primaryDataCenters, _ := findTopKeys(existingDataCenters)
// ensure data center count is within limit
if _, found := existingDataCenters[possibleLocation.DataCenter()]; !found {
// different from existing dcs
if len(existingDataCenters) < replicaPlacement.DiffDataCenterCount+1 {
// lack on different dcs
return true
} else {
// adding this would go over the different dcs limit
return false
}
}
// now this is same as one of the existing data center
if !isAmong(possibleLocation.DataCenter(), primaryDataCenters) {
// not on one of the primary dcs
return false
}
// now this is one of the primary dcs
primaryDcRacks := make(map[string]int)
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for _, replica := range replicas {
if replica.location.DataCenter() != possibleLocation.DataCenter() {
continue
}
primaryDcRacks[replica.location.Rack()] += 1
}
primaryRacks, _ := findTopKeys(primaryDcRacks)
sameRackCount := primaryDcRacks[possibleLocation.Rack()]
// ensure rack count is within limit
if _, found := primaryDcRacks[possibleLocation.Rack()]; !found {
// different from existing racks
if len(primaryDcRacks) < replicaPlacement.DiffRackCount+1 {
// lack on different racks
return true
} else {
// adding this would go over the different racks limit
return false
}
}
// now this is same as one of the existing racks
if !isAmong(possibleLocation.Rack(), primaryRacks) {
// not on the primary rack
return false
}
// now this is on the primary rack
// different from existing data nodes
if sameRackCount < replicaPlacement.SameRackCount+1 {
// lack on same rack
return true
} else {
// adding this would go over the same data node limit
return false
}
}
func findTopKeys(m map[string]int) (topKeys []string, max int) {
for k, c := range m {
if max < c {
topKeys = topKeys[:0]
topKeys = append(topKeys, k)
max = c
} else if max == c {
topKeys = append(topKeys, k)
}
}
return
}
func isAmong(key string, keys []string) bool {
for _, k := range keys {
if k == key {
return true
}
}
return false
}
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type VolumeReplica struct {
location *location
info *master_pb.VolumeInformationMessage
}
type location struct {
dc string
rack string
dataNode *master_pb.DataNodeInfo
}
func newLocation(dc, rack string, dataNode *master_pb.DataNodeInfo) location {
return location{
dc: dc,
rack: rack,
dataNode: dataNode,
}
}
func (l location) String() string {
return fmt.Sprintf("%s %s %s", l.dc, l.rack, l.dataNode.Id)
}
func (l location) Rack() string {
return fmt.Sprintf("%s %s", l.dc, l.rack)
}
func (l location) DataCenter() string {
return l.dc
}
func pickOneReplicaToCopyFrom(replicas []*VolumeReplica) *VolumeReplica {
mostRecent := replicas[0]
for _, replica := range replicas {
if replica.info.ModifiedAtSecond > mostRecent.info.ModifiedAtSecond {
mostRecent = replica
}
}
return mostRecent
}
func countReplicas(replicas []*VolumeReplica) (diffDc, diffRack, diffNode map[string]int) {
diffDc = make(map[string]int)
diffRack = make(map[string]int)
diffNode = make(map[string]int)
for _, replica := range replicas {
diffDc[replica.location.DataCenter()] += 1
diffRack[replica.location.Rack()] += 1
diffNode[replica.location.String()] += 1
}
return
}
func pickOneReplicaToDelete(replicas []*VolumeReplica, replicaPlacement *super_block.ReplicaPlacement) *VolumeReplica {
allSame := true
oldest := replicas[0]
for _, replica := range replicas {
if replica.info.ModifiedAtSecond < oldest.info.ModifiedAtSecond {
oldest = replica
allSame = false
}
}
if !allSame {
return oldest
}
// TODO what if all the replicas have the same timestamp?
return oldest
}