Merge pull request etcd-io#16376 from geetasg/pr6

Update etcdutl restore to create v2 snapshot from v3

etcdutl/snapshot/v3_snapshot.go

@@ -38,7 +38,6 @@ import (
 	"go.etcd.io/etcd/server/v3/etcdserver"
 	"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/storage/backend"
 	"go.etcd.io/etcd/server/v3/storage/mvcc"
@@ -472,9 +471,7 @@ func (s *v3Manager) saveWALAndSnap() (*raftpb.HardState, error) {
 		return nil, err
 	}
 
-	// add members again to persist them to the store we create.
-	st := v2store.New(etcdserver.StoreClusterPrefix, etcdserver.StoreKeysPrefix)
-	s.cl.SetStore(st)
+	// add members again to persist them to the backend we create.
 	be := backend.NewDefaultBackend(s.lg, s.outDbPath())
 	defer be.Close()
 	s.cl.SetBackend(schema.NewMembershipBackend(s.lg, be))
@@ -534,15 +531,11 @@ func (s *v3Manager) saveWALAndSnap() (*raftpb.HardState, error) {
 		return nil, err
 	}
 
-	b, berr := st.Save()
-	if berr != nil {
-		return nil, berr
-	}
 	confState := raftpb.ConfState{
 		Voters: nodeIDs,
 	}
 	raftSnap := raftpb.Snapshot{
-		Data: b,
+		Data: etcdserver.GetMembershipInfoInV2Format(s.lg, s.cl),
 		Metadata: raftpb.SnapshotMetadata{
 			Index:     commit,
 			Term:      term,

tests/e2e/cluster_downgrade_test.go

@@ -29,8 +29,12 @@ import (
 
 	"go.etcd.io/etcd/api/v3/version"
 	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/client/pkg/v3/types"
 	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"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/storage/datadir"
 	"go.etcd.io/etcd/tests/v3/framework/config"
 	"go.etcd.io/etcd/tests/v3/framework/e2e"
@@ -293,6 +297,23 @@ func verifySnapshot(t *testing.T, epc *e2e.EtcdProcessCluster) {
 	t.Logf("All members have a valid snapshot")
 }
 
+func verifySnapshotMembers(t *testing.T, epc *e2e.EtcdProcessCluster, expectedMembers *clientv3.MemberListResponse) {
+	for i := range epc.Procs {
+		t.Logf("Verifying snapshot for member %d", i)
+		ss := snap.New(epc.Cfg.Logger, datadir.ToSnapDir(epc.Procs[i].Config().DataDirPath))
+		snap, err := ss.Load()
+		st := v2store.New(etcdserver.StoreClusterPrefix, etcdserver.StoreKeysPrefix)
+		err = st.Recovery(snap.Data)
+		assert.NoError(t, err)
+		for _, m := range expectedMembers.Members {
+			_, err := st.Get(membership.MemberStoreKey(types.ID(m.ID)), true, true)
+			assert.NoError(t, err)
+		}
+		t.Logf("Verifed snapshot for member %d", i)
+	}
+	t.Log("All members have a valid snapshot")
+}
+
 func getMembersAndKeys(t *testing.T, epc *e2e.EtcdProcessCluster) (*clientv3.MemberListResponse, *clientv3.GetResponse) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()

tests/e2e/ctl_v3_snapshot_test.go

@@ -358,6 +358,9 @@ func TestRestoreCompactionRevBump(t *testing.T) {
 		require.NoError(t, ctl.Put(context.Background(), unsnappedKVs[i].Key, unsnappedKVs[i].Val, config.PutOptions{}))
 	}
 
+	membersBefore, err := ctl.MemberList(context.Background(), false)
+	require.NoError(t, err)
+
 	t.Log("Stopping the original server...")
 	require.NoError(t, epc.Stop())
 
@@ -380,12 +383,16 @@ func TestRestoreCompactionRevBump(t *testing.T) {
 
 	t.Log("(Re)starting the etcd member using the restored snapshot...")
 	epc.Procs[0].Config().DataDirPath = newDataDir
+
 	for i := range epc.Procs[0].Config().Args {
 		if epc.Procs[0].Config().Args[i] == "--data-dir" {
 			epc.Procs[0].Config().Args[i+1] = newDataDir
 		}
 	}
 
+	// Verify that initial snapshot is created by the restore operation
+	verifySnapshotMembers(t, epc, membersBefore)
+
 	require.NoError(t, epc.Restart(context.Background()))
 
 	t.Log("Ensuring the restored member has the correct data...")