Unable to restore etcd backup v2

[r7vme]

Restoring v2 snapshot gives following error

etcd2|⇒ etcd -debug -data-dir /home/rs/tmp/etcd2/locallab-etcd-backup-v2-2017-07-27T20-50-05/ -force-new-cluster 
2017-07-27 23:53:08.302419 I | etcdmain: etcd Version: 3.2.0-rc.0+git
2017-07-27 23:53:08.302452 I | etcdmain: Git SHA: Not provided (use ./build instead of go build)
2017-07-27 23:53:08.302458 I | etcdmain: Go Version: go1.8.1
2017-07-27 23:53:08.302463 I | etcdmain: Go OS/Arch: linux/amd64
2017-07-27 23:53:08.302467 I | etcdmain: setting maximum number of CPUs to 4, total number of available CPUs is 4
2017-07-27 23:53:08.302500 N | etcdmain: the server is already initialized as member before, starting as etcd member...
2017-07-27 23:53:08.302861 I | embed: listening for peers on http://localhost:2380
2017-07-27 23:53:08.302979 I | embed: listening for client requests on localhost:2379
2017-07-27 23:53:08.331789 I | etcdserver: recovered store from snapshot at index 39809605
2017-07-27 23:53:08.343783 C | etcdserver: recovering backend from snapshot error: database snapshot file path error: snap: snapshot file doesn't exist
panic: recovering backend from snapshot error: database snapshot file path error: snap: snapshot file doesn't exist
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0xb5454c]

goroutine 1 [running]:
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdserver.NewServer.func1(0xc4201b2678, 0xc4201b2470)
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdserver/server.go:279 +0x3c
panic(0xd67640, 0xc4201d8210)
        /usr/lib/go/src/runtime/panic.go:489 +0x2cf
github.com/coreos/etcd/cmd/vendor/github.com/coreos/pkg/capnslog.(*PackageLogger).Panicf(0xc42016dde0, 0xf3684f, 0x2a, 0xc4201b24e0, 0x1, 0x1)
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/pkg/capnslog/pkg_logger.go:75 +0x15c
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdserver.NewServer(0xc420246000, 0x0, 0x1612180, 0xc42023e060)
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdserver/server.go:374 +0x2e52
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/embed.StartEtcd(0xc420199180, 0x0, 0x0, 0x0)
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/embed/etcd.go:147 +0x7c0
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain.startEtcd(0xc420199180, 0x6, 0xf132b8, 0x6, 0x1)
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain/etcd.go:186 +0x58
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain.startEtcdOrProxyV2()
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain/etcd.go:103 +0x15ba
github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain.Main()
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/vendor/github.com/coreos/etcd/etcdmain/main.go:39 +0x61
main.main()
        /home/rs/src/go/src/github.com/coreos/etcd/cmd/etcd/main.go:28 +0x20

[r7vme]

Created upstream bug etcd-io/etcd#8331

Also found that in case of successful v2 backup we have both v2 and v3. Tested locally.
etcd-io/etcd#7002 (comment)

[r7vme]

As workaround, before restoration do

touch $BACKUP_DIR/member/snap/db

It's important to use same 3.1.7 version of etcd. With 3.2.0 restoration is not working.

[r7vme]

See restoration guide: https://github.com/giantswarm/etcd-backup/blob/master/Documentation/01-restore-etcd-from-backups.md