// InitialState implements the raft.Storage interface.
func (r *Range) InitialState() (raftpb.HardState, raftpb.ConfState, error) {
var hs raftpb.HardState
found, err := engine.MVCCGetProto(r.rm.Engine(), keys.RaftHardStateKey(r.Desc().RaftID),
proto.ZeroTimestamp, true, nil, &hs)
if err != nil {
return raftpb.HardState{}, raftpb.ConfState{}, err
}
if !found {
// We don't have a saved HardState, so set up the defaults.
if r.isInitialized() {
// Set the initial log term.
hs.Term = raftInitialLogTerm
hs.Commit = raftInitialLogIndex
atomic.StoreUint64(&r.lastIndex, raftInitialLogIndex)
} else {
// This is a new range we are receiving from another node. Start
// from zero so we will receive a snapshot.
atomic.StoreUint64(&r.lastIndex, 0)
}
}
var cs raftpb.ConfState
// For uninitalized ranges, membership is unknown at this point.
if found || r.isInitialized() {
for _, rep := range r.Desc().Replicas {
cs.Nodes = append(cs.Nodes, uint64(proto.MakeRaftNodeID(rep.NodeID, rep.StoreID)))
}
}
return hs, cs, nil
}
func updateHardState(eng engine.ReadWriter, s storagebase.ReplicaState) error {
// Load a potentially existing HardState as we may need to preserve
// information about cast votes. For example, during a Split for which
// another node's new right-hand side has contacted us before our left-hand
// side called in here to create the group.
rangeID := s.Desc.RangeID
oldHS, err := loadHardState(eng, rangeID)
if err != nil {
return err
}
newHS := raftpb.HardState{
Term: s.TruncatedState.Term,
Commit: s.RaftAppliedIndex,
}
if !raft.IsEmptyHardState(oldHS) {
if oldHS.Commit > newHS.Commit {
newHS.Commit = oldHS.Commit
}
if oldHS.Term > newHS.Term {
newHS.Term = oldHS.Term
}
newHS.Vote = oldHS.Vote
}
return setHardState(eng, rangeID, newHS)
}
// writeInitialState bootstraps a new Raft group (i.e. it is called when we
// bootstrap a Range, or when setting up the right hand side of a split).
// Its main task is to persist a consistent Raft (and associated Replica) state
// which does not start from zero but presupposes a few entries already having
// applied.
// The supplied MVCCStats are used for the Stats field after adjusting for
// persisting the state itself, and the updated stats are returned.
func writeInitialState(
eng engine.ReadWriter, ms enginepb.MVCCStats, desc roachpb.RangeDescriptor,
) (enginepb.MVCCStats, error) {
rangeID := desc.RangeID
var s storagebase.ReplicaState
s.TruncatedState = &roachpb.RaftTruncatedState{
Term: raftInitialLogTerm,
Index: raftInitialLogIndex,
}
s.RaftAppliedIndex = s.TruncatedState.Index
s.Desc = &roachpb.RangeDescriptor{
RangeID: rangeID,
}
s.Stats = ms
newMS, err := saveState(eng, s)
if err != nil {
return enginepb.MVCCStats{}, err
}
// Load a potentially existing HardState as we may need to preserve
// information about cast votes. For example, during a Split for which
// another node's new right-hand side has contacted us before our left-hand
// side called in here to create the group.
oldHS, err := loadHardState(eng, rangeID)
if err != nil {
return enginepb.MVCCStats{}, err
}
newHS := raftpb.HardState{
Term: s.TruncatedState.Term,
Commit: s.TruncatedState.Index,
}
if !raft.IsEmptyHardState(oldHS) {
if oldHS.Commit > newHS.Commit {
newHS.Commit = oldHS.Commit
}
if oldHS.Term > newHS.Term {
newHS.Term = oldHS.Term
}
newHS.Vote = oldHS.Vote
}
if err := setHardState(eng, rangeID, newHS); err != nil {
return enginepb.MVCCStats{}, err
}
if err := setLastIndex(eng, rangeID, s.TruncatedState.Index); err != nil {
return enginepb.MVCCStats{}, err
}
return newMS, nil
}
// InitialState implements the raft.Storage interface.
func (r *Replica) InitialState() (raftpb.HardState, raftpb.ConfState, error) {
var hs raftpb.HardState
desc := r.Desc()
found, err := engine.MVCCGetProto(r.store.Engine(), keys.RaftHardStateKey(desc.RangeID),
roachpb.ZeroTimestamp, true, nil, &hs)
if err != nil {
return raftpb.HardState{}, raftpb.ConfState{}, err
}
initialized := r.isInitialized()
if !found {
// We don't have a saved HardState, so set up the defaults.
if initialized {
// Set the initial log term.
hs.Term = raftInitialLogTerm
hs.Commit = raftInitialLogIndex
atomic.StoreUint64(&r.lastIndex, raftInitialLogIndex)
} else {
// This is a new range we are receiving from another node. Start
// from zero so we will receive a snapshot.
atomic.StoreUint64(&r.lastIndex, 0)
}
} else if initialized && hs.Commit == 0 {
// Normally, when the commit index changes, raft gives us a new
// commit index to persist, however, during initialization, which
// occurs entirely in cockroach, raft has no knowledge of this.
// By setting this to the initial log index, we avoid a panic in
// raft caused by this inconsistency.
hs.Commit = raftInitialLogIndex
}
var cs raftpb.ConfState
// For uninitalized ranges, membership is unknown at this point.
if found || initialized {
for _, rep := range desc.Replicas {
cs.Nodes = append(cs.Nodes, uint64(rep.ReplicaID))
}
}
return hs, cs, nil
}
func (n *Node) readWAL(ctx context.Context, snapshot *raftpb.Snapshot, forceNewCluster bool) (err error) {
var (
walsnap walpb.Snapshot
metadata []byte
st raftpb.HardState
ents []raftpb.Entry
)
if snapshot != nil {
walsnap.Index = snapshot.Metadata.Index
walsnap.Term = snapshot.Metadata.Term
}
repaired := false
for {
if n.wal, err = wal.Open(n.walDir(), walsnap); err != nil {
return fmt.Errorf("open WAL error: %v", err)
}
if metadata, st, ents, err = n.wal.ReadAll(); err != nil {
if err := n.wal.Close(); err != nil {
return err
}
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
return fmt.Errorf("read WAL error (%v) and cannot be repaired", err)
}
if !wal.Repair(n.walDir()) {
return fmt.Errorf("WAL error (%v) cannot be repaired", err)
}
log.G(ctx).Infof("repaired WAL error (%v)", err)
repaired = true
continue
}
break
}
defer func() {
if err != nil {
if walErr := n.wal.Close(); walErr != nil {
n.Config.Logger.Errorf("error closing raft WAL: %v", walErr)
}
}
}()
var raftNode api.RaftMember
if err := raftNode.Unmarshal(metadata); err != nil {
return fmt.Errorf("error unmarshalling WAL metadata: %v", err)
}
n.Config.ID = raftNode.RaftID
// All members that are no longer part of the cluster must be added to
// the removed list right away, so that we don't try to connect to them
// before processing the configuration change entries, which could make
// us get stuck.
for _, ent := range ents {
if ent.Index <= st.Commit && ent.Type == raftpb.EntryConfChange {
var cc raftpb.ConfChange
if err := cc.Unmarshal(ent.Data); err != nil {
return fmt.Errorf("error unmarshalling config change: %v", err)
}
if cc.Type == raftpb.ConfChangeRemoveNode {
n.cluster.RemoveMember(cc.NodeID)
}
}
}
if forceNewCluster {
// discard the previously uncommitted entries
for i, ent := range ents {
if ent.Index > st.Commit {
log.G(context.Background()).Infof("discarding %d uncommitted WAL entries ", len(ents)-i)
ents = ents[:i]
break
}
}
// force append the configuration change entries
toAppEnts := createConfigChangeEnts(getIDs(snapshot, ents), uint64(n.Config.ID), st.Term, st.Commit)
// All members that are being removed as part of the
// force-new-cluster process must be added to the
// removed list right away, so that we don't try to
// connect to them before processing the configuration
// change entries, which could make us get stuck.
for _, ccEnt := range toAppEnts {
if ccEnt.Type == raftpb.EntryConfChange {
var cc raftpb.ConfChange
if err := cc.Unmarshal(ccEnt.Data); err != nil {
return fmt.Errorf("error unmarshalling force-new-cluster config change: %v", err)
}
if cc.Type == raftpb.ConfChangeRemoveNode {
n.cluster.RemoveMember(cc.NodeID)
}
}
}
ents = append(ents, toAppEnts...)
// force commit newly appended entries
err := n.wal.Save(st, toAppEnts)
if err != nil {
log.G(context.Background()).Fatalf("%v", err)
}
if len(toAppEnts) != 0 {
st.Commit = toAppEnts[len(toAppEnts)-1].Index
}
}
if snapshot != nil {
if err := n.raftStore.ApplySnapshot(*snapshot); err != nil {
return err
}
}
if err := n.raftStore.SetHardState(st); err != nil {
return err
}
if err := n.raftStore.Append(ents); err != nil {
return err
}
return nil
}
func (n *Node) readWAL(ctx context.Context, snapshot *raftpb.Snapshot, forceNewCluster bool) (err error) {
var (
walsnap walpb.Snapshot
metadata []byte
st raftpb.HardState
ents []raftpb.Entry
)
if snapshot != nil {
walsnap.Index = snapshot.Metadata.Index
walsnap.Term = snapshot.Metadata.Term
}
repaired := false
for {
if n.wal, err = wal.Open(n.walDir(), walsnap); err != nil {
return fmt.Errorf("open wal error: %v", err)
}
if metadata, st, ents, err = n.wal.ReadAll(); err != nil {
if err := n.wal.Close(); err != nil {
return err
}
// we can only repair ErrUnexpectedEOF and we never repair twice.
if repaired || err != io.ErrUnexpectedEOF {
return fmt.Errorf("read wal error (%v) and cannot be repaired", err)
}
if !wal.Repair(n.walDir()) {
return fmt.Errorf("WAL error (%v) cannot be repaired", err)
}
log.G(ctx).Infof("repaired WAL error (%v)", err)
repaired = true
continue
}
break
}
defer func() {
if err != nil {
if walErr := n.wal.Close(); walErr != nil {
n.Config.Logger.Errorf("error closing raft WAL: %v", walErr)
}
}
}()
var raftNode api.RaftMember
if err := raftNode.Unmarshal(metadata); err != nil {
return fmt.Errorf("error unmarshalling wal metadata: %v", err)
}
n.Config.ID = raftNode.RaftID
if forceNewCluster {
// discard the previously uncommitted entries
for i, ent := range ents {
if ent.Index > st.Commit {
log.G(context.Background()).Infof("discarding %d uncommitted WAL entries ", len(ents)-i)
ents = ents[:i]
break
}
}
// force append the configuration change entries
toAppEnts := createConfigChangeEnts(getIDs(snapshot, ents), uint64(n.Config.ID), st.Term, st.Commit)
ents = append(ents, toAppEnts...)
// force commit newly appended entries
err := n.wal.Save(st, toAppEnts)
if err != nil {
log.G(context.Background()).Fatalf("%v", err)
}
if len(toAppEnts) != 0 {
st.Commit = toAppEnts[len(toAppEnts)-1].Index
}
}
if snapshot != nil {
if err := n.raftStore.ApplySnapshot(*snapshot); err != nil {
return err
}
}
if err := n.raftStore.SetHardState(st); err != nil {
return err
}
if err := n.raftStore.Append(ents); err != nil {
return err
}
return nil
}