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v2 etcdctl backup: producing consistent state of membership

release-3.5
Piotr Tabor 2021-04-02 21:08:03 +02:00
parent a70386a1a4
commit 067521981e
5 changed files with 167 additions and 63 deletions
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120
etcdctl/ctlv2/command/backup_command.go
View File

@ -15,7 +15,6 @@
package command
import (
"encoding/binary"
"log"
"os"
"path"
@ -25,11 +24,15 @@ import (
"go.etcd.io/etcd/api/v3/etcdserverpb"
"go.etcd.io/etcd/client/pkg/v3/fileutil"
"go.etcd.io/etcd/client/pkg/v3/types"
"go.etcd.io/etcd/pkg/v3/idutil"
"go.etcd.io/etcd/pkg/v3/pbutil"
"go.etcd.io/etcd/raft/v3/raftpb"
"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
"go.etcd.io/etcd/server/v3/etcdserver/cindex"
"go.etcd.io/etcd/server/v3/mvcc/backend"
"go.etcd.io/etcd/server/v3/wal"
"go.etcd.io/etcd/server/v3/wal/walpb"
@ -54,11 +57,41 @@ func NewBackupCommand() cli.Command {
}
}
type desiredCluster struct {
clusterId types.ID
nodeId types.ID
members []*membership.Member
confState raftpb.ConfState
}
func newDesiredCluster() desiredCluster {
idgen := idutil.NewGenerator(0, time.Now())
nodeID := idgen.Next()
clusterID := idgen.Next()
return desiredCluster{
clusterId: types.ID(clusterID),
nodeId: types.ID(nodeID),
members: []*membership.Member{
{
ID: types.ID(nodeID),
Attributes: membership.Attributes{
Name: "etcdctl-v2-backup",
},
RaftAttributes: membership.RaftAttributes{
PeerURLs: []string{"http://use-flag--force-new-cluster:2080"},
}}},
confState: raftpb.ConfState{Voters: []uint64{nodeID}},
}
}
// handleBackup handles a request that intends to do a backup.
func handleBackup(c *cli.Context) error {
var srcWAL string
var destWAL string
lg := zap.NewExample()
withV3 := c.Bool("with-v3")
srcSnap := filepath.Join(c.String("data-dir"), "member", "snap")
destSnap := filepath.Join(c.String("backup-dir"), "member", "snap")
@ -79,13 +112,12 @@ func handleBackup(c *cli.Context) error {
log.Fatalf("failed creating backup snapshot dir %v: %v", destSnap, err)
}
walsnap := saveSnap(destSnap, srcSnap)
metadata, state, ents := loadWAL(srcWAL, walsnap, withV3)
saveDB(filepath.Join(destSnap, "db"), filepath.Join(srcSnap, "db"), state.Commit, withV3)
desired := newDesiredCluster()
idgen := idutil.NewGenerator(0, time.Now())
metadata.NodeID = idgen.Next()
metadata.ClusterID = idgen.Next()
walsnap := saveSnap(lg, destSnap, srcSnap, &desired)
metadata, state, ents := loadWAL(srcWAL, walsnap, withV3)
destDbPath := filepath.Join(destSnap, "db")
saveDB(lg, destDbPath, filepath.Join(srcSnap, "db"), state.Commit, &desired, withV3)
neww, err := wal.Create(zap.NewExample(), destWAL, pbutil.MustMarshal(&metadata))
if err != nil {
@ -102,15 +134,17 @@ func handleBackup(c *cli.Context) error {
return nil
}
func saveSnap(destSnap, srcSnap string) (walsnap walpb.Snapshot) {
ss := snap.New(zap.NewExample(), srcSnap)
func saveSnap(lg *zap.Logger, destSnap, srcSnap string, desired *desiredCluster) (walsnap walpb.Snapshot) {
ss := snap.New(lg, srcSnap)
snapshot, err := ss.Load()
if err != nil && err != snap.ErrNoSnapshot {
log.Fatal(err)
}
if snapshot != nil {
walsnap.Index, walsnap.Term, walsnap.ConfState = snapshot.Metadata.Index, snapshot.Metadata.Term, &snapshot.Metadata.ConfState
newss := snap.New(zap.NewExample(), destSnap)
walsnap.Index, walsnap.Term, walsnap.ConfState = snapshot.Metadata.Index, snapshot.Metadata.Term, &desired.confState
newss := snap.New(lg, destSnap)
snapshot.Metadata.ConfState = desired.confState
snapshot.Data = mustTranslateV2store(lg, snapshot.Data, desired)
if err = newss.SaveSnap(*snapshot); err != nil {
log.Fatal(err)
}
@ -118,6 +152,26 @@ func saveSnap(destSnap, srcSnap string) (walsnap walpb.Snapshot) {
return walsnap
}
// mustTranslateV2store processes storeData such that they match 'desiredCluster'.
// In particular the method overrides membership information.
func mustTranslateV2store(lg *zap.Logger, storeData []byte, desired *desiredCluster) []byte {
st := v2store.New()
if err := st.Recovery(storeData); err != nil {
lg.Panic("cannot translate v2store", zap.Error(err))
}
raftCluster := membership.NewClusterFromMembers(lg, desired.clusterId, desired.members)
raftCluster.SetID(desired.nodeId, desired.clusterId)
raftCluster.SetStore(st)
raftCluster.PushMembershipToStorage()
outputData, err := st.Save()
if err != nil {
lg.Panic("cannot save v2store", zap.Error(err))
}
return outputData
}
func loadWAL(srcWAL string, walsnap walpb.Snapshot, v3 bool) (etcdserverpb.Metadata, raftpb.HardState, []raftpb.Entry) {
w, err := wal.OpenForRead(zap.NewExample(), srcWAL, walsnap)
if err != nil {
@ -190,7 +244,8 @@ func loadWAL(srcWAL string, walsnap walpb.Snapshot, v3 bool) (etcdserverpb.Metad
}
// saveDB copies the v3 backend and strips cluster information.
func saveDB(destDB, srcDB string, idx uint64, v3 bool) {
func saveDB(lg *zap.Logger, destDB, srcDB string, idx uint64, desired *desiredCluster, v3 bool) {
// open src db to safely copy db state
if v3 {
var src *bolt.DB
@ -229,37 +284,26 @@ func saveDB(destDB, srcDB string, idx uint64, v3 bool) {
}
}
db, err := bolt.Open(destDB, 0644, &bolt.Options{})
if err != nil {
log.Fatal(err)
}
tx, err := db.Begin(true)
if err != nil {
be := backend.NewDefaultBackend(destDB)
defer be.Close()
if err := membership.TrimClusterFromBackend(be); err != nil {
log.Fatal(err)
}
// remove membership information; should be clobbered by --force-new-cluster
// TODO: Consider refactoring to use backend.Backend instead of bolt
// and membership.TrimMembershipFromBackend.
for _, bucket := range []string{"members", "members_removed", "cluster"} {
tx.DeleteBucket([]byte(bucket))
}
raftCluster := membership.NewClusterFromMembers(lg, desired.clusterId, desired.members)
raftCluster.SetID(desired.nodeId, desired.clusterId)
raftCluster.SetBackend(be)
raftCluster.PushMembershipToStorage()
// update consistent index to match hard state
if !v3 {
idxBytes := make([]byte, 8)
binary.BigEndian.PutUint64(idxBytes, idx)
b, err := tx.CreateBucketIfNotExists([]byte("meta"))
if err != nil {
log.Fatal(err)
}
b.Put([]byte("consistent_index"), idxBytes)
tx := be.BatchTx()
tx.Lock()
defer tx.Unlock()
tx.UnsafeCreateBucket([]byte("meta"))
ci := cindex.NewConsistentIndex(tx)
ci.SetConsistentIndex(idx)
ci.UnsafeSave(tx)
}
if err := tx.Commit(); err != nil {
log.Fatal(err)
}
if err := db.Close(); err != nil {
log.Fatal(err)
}
}

48
etcdctl/snapshot/v3_snapshot.go
View File

@ -32,7 +32,6 @@ import (
"go.etcd.io/etcd/client/pkg/v3/types"
"go.etcd.io/etcd/client/v3"
"go.etcd.io/etcd/client/v3/snapshot"
"go.etcd.io/etcd/pkg/v3/traceutil"
"go.etcd.io/etcd/raft/v3"
"go.etcd.io/etcd/raft/v3/raftpb"
"go.etcd.io/etcd/server/v3/config"
@ -40,6 +39,7 @@ import (
"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
"go.etcd.io/etcd/server/v3/etcdserver/cindex"
"go.etcd.io/etcd/server/v3/mvcc/backend"
"go.etcd.io/etcd/server/v3/wal"
"go.etcd.io/etcd/server/v3/wal/walpb"
@ -255,12 +255,19 @@ func (s *v3Manager) Restore(cfg RestoreConfig) error {
zap.String("snap-dir", s.snapDir),
zap.Stack("stack"),
)
if err = s.saveDB(); err != nil {
return err
}
if err = s.saveWALAndSnap(); err != nil {
hardstate, err := s.saveWALAndSnap()
if err != nil {
return err
}
if err := s.updateCIndex(hardstate.Commit); err != nil {
return err
}
s.lg.Info(
"restored snapshot",
zap.String("path", s.srcDbPath),
@ -295,7 +302,7 @@ func (s *v3Manager) saveDB() error {
}
func (s *v3Manager) copyAndVerifyDB() error {
srcf, ferr := os.OpenFile(s.srcDbPath, os.O_RDONLY, 0600)
srcf, ferr := os.Open(s.srcDbPath)
if ferr != nil {
return ferr
}
@ -373,9 +380,9 @@ func (s *v3Manager) copyAndVerifyDB() error {
// saveWALAndSnap creates a WAL for the initial cluster
//
// TODO: This code ignores learners !!!
func (s *v3Manager) saveWALAndSnap() error {
func (s *v3Manager) saveWALAndSnap() (*raftpb.HardState, error) {
if err := fileutil.CreateDirAll(s.walDir); err != nil {
return err
return nil, err
}
// add members again to persist them to the store we create.
@ -392,11 +399,11 @@ func (s *v3Manager) saveWALAndSnap() error {
md := &etcdserverpb.Metadata{NodeID: uint64(m.ID), ClusterID: uint64(s.cl.ID())}
metadata, merr := md.Marshal()
if merr != nil {
return merr
return nil, merr
}
w, walerr := wal.Create(s.lg, s.walDir, metadata)
if walerr != nil {
return walerr
return nil, walerr
}
defer w.Close()
@ -404,7 +411,7 @@ func (s *v3Manager) saveWALAndSnap() error {
for i, id := range s.cl.MemberIDs() {
ctx, err := json.Marshal((*s.cl).Member(id))
if err != nil {
return err
return nil, err
}
peers[i] = raft.Peer{ID: uint64(id), Context: ctx}
}
@ -420,7 +427,7 @@ func (s *v3Manager) saveWALAndSnap() error {
}
d, err := cc.Marshal()
if err != nil {
return err
return nil, err
}
ents[i] = raftpb.Entry{
Type: raftpb.EntryConfChange,
@ -431,17 +438,18 @@ func (s *v3Manager) saveWALAndSnap() error {
}
commit, term := uint64(len(ents)), uint64(1)
if err := w.Save(raftpb.HardState{
hardState := raftpb.HardState{
Term: term,
Vote: peers[0].ID,
Commit: commit,
}, ents); err != nil {
return err
}
if err := w.Save(hardState, ents); err != nil {
return nil, err
}
b, berr := st.Save()
if berr != nil {
return berr
return nil, berr
}
confState := raftpb.ConfState{
Voters: nodeIDs,
@ -456,7 +464,17 @@ func (s *v3Manager) saveWALAndSnap() error {
}
sn := snap.New(s.lg, s.snapDir)
if err := sn.SaveSnap(raftSnap); err != nil {
return err
return nil, err
}
return w.SaveSnapshot(walpb.Snapshot{Index: commit, Term: term, ConfState: &confState})
snapshot := walpb.Snapshot{Index: commit, Term: term, ConfState: &confState}
return &hardState, w.SaveSnapshot(snapshot)
}
func (s *v3Manager) updateCIndex(commit uint64) error {
be := backend.NewDefaultBackend(s.outDbPath())
defer be.Close()
ci := cindex.NewConsistentIndex(be.BatchTx())
ci.SetConsistentIndex(commit)
ci.UnsafeSave(be.BatchTx())
return nil
}

17
server/etcdserver/api/membership/cluster.go
View File

@ -859,3 +859,20 @@ func (c *RaftCluster) VotingMemberIDs() []types.ID {
sort.Sort(types.IDSlice(ids))
return ids
}
// PushMembershipToStorage is overriding storage information about cluster's
// members, such that they fully reflect internal RaftCluster's storage.
func (c *RaftCluster) PushMembershipToStorage() {
if c.be != nil {
TrimMembershipFromBackend(c.lg, c.be)
for _, m := range c.members {
mustSaveMemberToBackend(c.lg, c.be, m)
}
}
if c.v2store != nil {
TrimMembershipFromV2Store(c.lg, c.v2store)
for _, m := range c.members {
mustSaveMemberToStore(c.lg, c.v2store, m)
}
}
}

7
server/etcdserver/api/membership/member.go
View File

@ -20,6 +20,7 @@ import (
"fmt"
"math/rand"
"sort"
"strings"
"time"
"go.etcd.io/etcd/client/pkg/v3/types"
@ -61,12 +62,10 @@ func NewMemberAsLearner(name string, peerURLs types.URLs, clusterName string, no
}
func computeMemberId(peerURLs types.URLs, clusterName string, now *time.Time) types.ID {
var b []byte
peerURLstrs := peerURLs.StringSlice()
sort.Strings(peerURLstrs)
for _, p := range peerURLstrs {
b = append(b, []byte(p)...)
}
joinedPeerUrls := strings.Join(peerURLstrs, "")
b := []byte(joinedPeerUrls)
b = append(b, []byte(clusterName)...)
if now != nil {

38
server/etcdserver/api/membership/store.go
View File

@ -57,6 +57,8 @@ func mustSaveMemberToBackend(lg *zap.Logger, be backend.Backend, m *Member) {
tx.UnsafePut(membersBucketName, mkey, mvalue)
}
// TrimClusterFromBackend removes all information about cluster (versions)
// from the v3 backend.
func TrimClusterFromBackend(be backend.Backend) error {
tx := be.BatchTx()
tx.Lock()
@ -83,7 +85,7 @@ func readMembersFromBackend(lg *zap.Logger, be backend.Backend) (map[types.ID]*M
tx.RLock()
defer tx.RUnlock()
err := tx.UnsafeForEach(membersBucketName, func(k, v []byte) error {
memberId := MustParseMemberIDFromBytes(lg, k)
memberId := mustParseMemberIDFromBytes(lg, k)
m := &Member{ID: memberId}
if err := json.Unmarshal(v, &m); err != nil {
return err
@ -96,7 +98,7 @@ func readMembersFromBackend(lg *zap.Logger, be backend.Backend) (map[types.ID]*M
}
err = tx.UnsafeForEach(membersRemovedBucketName, func(k, v []byte) error {
memberId := MustParseMemberIDFromBytes(lg, k)
memberId := mustParseMemberIDFromBytes(lg, k)
removed[memberId] = true
return nil
})
@ -114,24 +116,48 @@ func mustReadMembersFromBackend(lg *zap.Logger, be backend.Backend) (map[types.I
return members, removed
}
// TrimMembershipFromBackend removes all information about members &
// removed_members from the v3 backend.
func TrimMembershipFromBackend(lg *zap.Logger, be backend.Backend) error {
lg.Info("Trimming membership information from the backend...")
tx := be.BatchTx()
tx.Lock()
defer tx.Unlock()
err := tx.UnsafeForEach(membersBucketName, func(k, v []byte) error {
tx.UnsafeDelete(membersBucketName, k)
lg.Debug("Removed member from the backend",
zap.Stringer("member", mustParseMemberIDFromBytes(lg, k)))
return nil
})
if err != nil {
return err
}
err = tx.UnsafeForEach(membersRemovedBucketName, func(k, v []byte) error {
return tx.UnsafeForEach(membersRemovedBucketName, func(k, v []byte) error {
tx.UnsafeDelete(membersRemovedBucketName, k)
lg.Debug("Removed removed_member from the backend",
zap.Stringer("member", mustParseMemberIDFromBytes(lg, k)))
return nil
})
if err != nil {
return err
}
// TrimMembershipFromV2Store removes all information about members &
// removed_members from the v2 store.
func TrimMembershipFromV2Store(lg *zap.Logger, s v2store.Store) error {
members, removed := membersFromStore(lg, s)
for mID := range members {
_, err := s.Delete(MemberStoreKey(mID), true, true)
if err != nil {
return err
}
}
for mID := range removed {
_, err := s.Delete(RemovedMemberStoreKey(mID), true, true)
if err != nil {
return err
}
}
return nil
}
@ -289,7 +315,7 @@ func MemberAttributesStorePath(id types.ID) string {
return path.Join(MemberStoreKey(id), attributesSuffix)
}
func MustParseMemberIDFromBytes(lg *zap.Logger, key []byte) types.ID {
func mustParseMemberIDFromBytes(lg *zap.Logger, key []byte) types.ID {
id, err := types.IDFromString(string(key))
if err != nil {
lg.Panic("failed to parse member id from key", zap.Error(err))