See [code changes](https://github.com/coreos/etcd/compare/v3.3.0-rc.3...v3.3.0-rc.4) and [v3.3 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_3.md) for any breaking changes.
See [code changes](https://github.com/coreos/etcd/compare/v3.3.0-rc.2...v3.3.0-rc.3) and [v3.3 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_3.md) for any breaking changes.
See [code changes](https://github.com/coreos/etcd/compare/v3.3.0-rc.1...v3.3.0-rc.2) and [v3.3 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_3.md) for any breaking changes.
See [code changes](https://github.com/coreos/etcd/compare/v3.3.0-rc.0...v3.3.0-rc.1) and [v3.3 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_3.md) for any breaking changes.
See [code changes](https://github.com/coreos/etcd/compare/v3.2.0...v3.3.0-rc.0) and [v3.3 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_3.md) for any breaking changes.
### Improved
- Use [`coreos/bbolt`](https://github.com/coreos/bbolt/releases) to replace [`boltdb/bolt`](https://github.com/boltdb/bolt#project-status).
- Fix [etcd database size grows until `mvcc: database space exceeded`](https://github.com/coreos/etcd/issues/8009).
- [Reduce memory allocation](https://github.com/coreos/etcd/pull/8428) on [Range operations](https://github.com/coreos/etcd/pull/8475).
- [Rate limit](https://github.com/coreos/etcd/pull/8099) and [randomize](https://github.com/coreos/etcd/pull/8101) lease revoke on restart or leader elections.
- Prevent [spikes in Raft proposal rate](https://github.com/coreos/etcd/issues/8096).
- Support `clientv3` balancer failover under [network faults/partitions](https://github.com/coreos/etcd/issues/8711).
- Better warning on [mismatched `--initial-cluster`](https://github.com/coreos/etcd/pull/8083) flag.
- Deprecate `grpclog.Logger`, upgrade to [`grpclog.LoggerV2`](https://github.com/coreos/etcd/pull/8533).
- Deprecate [`grpc.ErrClientConnTimeout`](https://github.com/coreos/etcd/pull/8505) errors in `clientv3`.
- Use [`MaxRecvMsgSize` and `MaxSendMsgSize`](https://github.com/coreos/etcd/pull/8437) to limit message size, in etcd server.
- Upgrade [`github.com/grpc-ecosystem/grpc-gateway`](https://github.com/grpc-ecosystem/grpc-gateway/releases) `v1.2.2` to `v1.3.0`.
- Translate [gRPC status error in v3 client `Snapshot` API](https://github.com/coreos/etcd/pull/9038).
- Upgrade [`github.com/ugorji/go/codec`](https://github.com/ugorji/go) for v2 `client`.
- [Regenerated](https://github.com/coreos/etcd/pull/8721) v2 `client` source code with latest `ugorji/go/codec`.
- v3 `etcdctl` [`lease timetolive LEASE_ID`](https://github.com/coreos/etcd/issues/9028) on expired lease now prints [`lease LEASE_ID already expired`](https://github.com/coreos/etcd/pull/9047).
-<=3.2 prints `lease LEASE_ID granted with TTL(0s), remaining(-1s)`.
### Added(`etcd`)
- Add [`--experimental-enable-v2v3`](https://github.com/coreos/etcd/pull/8407) flag to [emulate v2 API with v3](https://github.com/coreos/etcd/issues/6925).
- Add [`--experimental-corrupt-check-time`](https://github.com/coreos/etcd/pull/8420) flag to [raise corrupt alarm monitoring](https://github.com/coreos/etcd/issues/7125).
- Add [`--experimental-initial-corrupt-check`](https://github.com/coreos/etcd/pull/8554) flag to [check database hash before serving client/peer traffic](https://github.com/coreos/etcd/issues/8313).
- Add [`--max-txn-ops`](https://github.com/coreos/etcd/pull/7976) flag to [configure maximum number operations in transaction](https://github.com/coreos/etcd/issues/7826).
- Add [`--max-request-bytes`](https://github.com/coreos/etcd/pull/7968) flag to [configure maximum client request size](https://github.com/coreos/etcd/issues/7923).
- If not configured, it defaults to 1.5 MiB.
- Add [`--client-crl-file`, `--peer-crl-file`](https://github.com/coreos/etcd/pull/8124) flags for [Certificate revocation list](https://github.com/coreos/etcd/issues/4034).
- Add [`--peer-cert-allowed-cn`](https://github.com/coreos/etcd/pull/8616) flag to support [CN-based auth for inter-peer connection](https://github.com/coreos/etcd/issues/8262).
- Add [`--listen-metrics-urls`](https://github.com/coreos/etcd/pull/8242) flag for additional `/metrics` endpoints.
- Support [additional (non) TLS `/metrics` endpoints for a TLS-enabled cluster](https://github.com/coreos/etcd/pull/8282).
- e.g. `--listen-metrics-urls=https://localhost:2378,http://localhost:9379` to serve `/metrics` in secure port 2378 and insecure port 9379.
- Useful for [bypassing critical APIs when monitoring etcd](https://github.com/coreos/etcd/issues/8060).
- Add [`--auto-compaction-mode`](https://github.com/coreos/etcd/pull/8123) flag to [support revision-based compaction](https://github.com/coreos/etcd/issues/8098).
- Change `--auto-compaction-retention` flag to [accept string values](https://github.com/coreos/etcd/pull/8563) with [finer granularity](https://github.com/coreos/etcd/issues/8503).
- Serve [`/health` endpoint as unhealthy](https://github.com/coreos/etcd/pull/8272) when [alarm (e.g. `NOSPACE`) is raised or there's no leader](https://github.com/coreos/etcd/issues/8207).
- Define [`etcdhttp.Health`](https://godoc.org/github.com/coreos/etcd/etcdserver/api/etcdhttp#Health) struct with JSON encoder.
- Note that `"health"` field is [`string` type, not `bool`](https://github.com/coreos/etcd/pull/9143).
- [Remove `"errors"` field](https://github.com/coreos/etcd/pull/9162) since `v3.3.0-rc.3` (did exist only in `v3.3.0-rc.0`, `v3.3.0-rc.1`, `v3.3.0-rc.2`).
- Warn on [shadowed environment variables](https://github.com/coreos/etcd/pull/8385).
- Address [error on shadowed environment variables](https://github.com/coreos/etcd/issues/8380).
- etcd `v3.4` will exit on this error.
### Added(API)
- Support [ranges in transaction comparisons](https://github.com/coreos/etcd/pull/8025) for [disconnected linearized reads](https://github.com/coreos/etcd/issues/7924).
- Add [nested transactions](https://github.com/coreos/etcd/pull/8102) to extend [proxy use cases](https://github.com/coreos/etcd/issues/7857).
- Add [lease comparison target in transaction](https://github.com/coreos/etcd/pull/8324).
- Add [hash by revision](https://github.com/coreos/etcd/pull/8263) for [better corruption checking against boltdb](https://github.com/coreos/etcd/issues/8016).
### Added(`etcd/clientv3`)
- Add [health balancer](https://github.com/coreos/etcd/pull/8545) to fix [watch API hangs](https://github.com/coreos/etcd/issues/7247), improve [endpoint switch under network faults](https://github.com/coreos/etcd/issues/7941).
- [Refactor balancer](https://github.com/coreos/etcd/pull/8840) and add [client-side keepalive pings](https://github.com/coreos/etcd/pull/8199) to handle [network partitions](https://github.com/coreos/etcd/issues/8711).
- Add [`MaxCallSendMsgSize` and `MaxCallRecvMsgSize`](https://github.com/coreos/etcd/pull/9047) fields to [`clientv3.Config`](https://godoc.org/github.com/coreos/etcd/clientv3#Config).
- Fix [exceeded response size limit error in client-side](https://github.com/coreos/etcd/issues/9043).
- In previous versions(v3.2.10, v3.2.11), client response size was limited to only 4 MiB.
-`MaxCallSendMsgSize` default value is 2 MiB, if not configured.
-`MaxCallRecvMsgSize` default value is `math.MaxInt32`, if not configured.
- Accept [`Compare_LEASE`](https://github.com/coreos/etcd/pull/8324) in [`clientv3.Compare`](https://godoc.org/github.com/coreos/etcd/clientv3#Compare).
- Add [`LeaseValue` helper](https://github.com/coreos/etcd/pull/8488) to `Cmp``LeaseID` values in `Txn`.
- Add [`MoveLeader`](https://github.com/coreos/etcd/pull/8153) to `Maintenance`.
- Add [`HashKV`](https://github.com/coreos/etcd/pull/8351) to `Maintenance`.
- Add [`Leases`](https://github.com/coreos/etcd/pull/8358) to `Lease`.
- Add [`clientv3/ordering`](https://github.com/coreos/etcd/pull/8092) for enforce [ordering in serialized requests](https://github.com/coreos/etcd/issues/7623).
- Support [`watch [key] [range_end] -- [exec-command…]`](https://github.com/coreos/etcd/pull/8919), equivalent to [v2 `etcdctl exec-watch`](https://github.com/coreos/etcd/issues/8814).
- Make `watch -- [exec-command]` set environmental variables [`ETCD_WATCH_REVISION`, `ETCD_WATCH_EVENT_TYPE`, `ETCD_WATCH_KEY`, `ETCD_WATCH_VALUE`](https://github.com/coreos/etcd/pull/9142) for each event.
- Support [`watch` with environmental variables `ETCDCTL_WATCH_KEY` and `ETCDCTL_WATCH_RANGE_END`](https://github.com/coreos/etcd/pull/9142).
- Enable [`clientv3.WithRequireLeader(context.Context)` for `watch`](https://github.com/coreos/etcd/pull/8672) command.
- Print [`"del"` instead of `"delete"`](https://github.com/coreos/etcd/pull/8297) in `txn` interactive mode.
- Print [`ETCD_INITIAL_ADVERTISE_PEER_URLS` in `member add`](https://github.com/coreos/etcd/pull/8332).
### Added(metrics)
- Add [`etcd --listen-metrics-urls`](https://github.com/coreos/etcd/pull/8242) flag for additional `/metrics` endpoints.
- Useful for [bypassing critical APIs when monitoring etcd](https://github.com/coreos/etcd/issues/8060).
- To implement [Raft thesis 4.2.1 Catching up new servers](https://github.com/coreos/etcd/issues/8568).
-`Learner` node does not vote or promote itself.
### Added/Fixed(Security/Auth)
- Add [CRL based connection rejection](https://github.com/coreos/etcd/pull/8124) to manage [revoked certs](https://github.com/coreos/etcd/issues/4034).
- [Server accepts connections if IP matches, without checking DNS entries](https://github.com/coreos/etcd/pull/8223). For instance, if peer cert contains IP addresses and DNS names in Subject Alternative Name (SAN) field, and the remote IP address matches one of those IP addresses, server just accepts connection without further checking the DNS names.
- [Server supports reverse-lookup on wildcard DNS `SAN`](https://github.com/coreos/etcd/pull/8281). For instance, if peer cert contains only DNS names (no IP addresses) in Subject Alternative Name (SAN) field, server first reverse-lookups the remote IP address to get a list of names mapping to that address (e.g. `nslookup IPADDR`). Then accepts the connection if those names have a matching name with peer cert's DNS names (either by exact or wildcard match). If none is matched, server forward-lookups each DNS entry in peer cert (e.g. look up `example.default.svc` when the entry is `*.example.default.svc`), and accepts connection only when the host's resolved addresses have the matching IP address with the peer's remote IP address.
- Prevent [server panic from member update/add](https://github.com/coreos/etcd/pull/9174) with [wrong scheme URLs](https://github.com/coreos/etcd/issues/9173).
- Fix [`clientv3.WatchResponse.Canceled`](https://github.com/coreos/etcd/pull/8283) on [compacted watch request](https://github.com/coreos/etcd/issues/8231).
- Handle [WAL renaming failure on Windows](https://github.com/coreos/etcd/pull/8286).
- Make [peer dial timeout longer](https://github.com/coreos/etcd/pull/8599).
- See [coreos/etcd-operator#1300](https://github.com/coreos/etcd-operator/issues/1300) for more detail.
- Make server [wait up to request time-out](https://github.com/coreos/etcd/pull/8267) with [pending RPCs](https://github.com/coreos/etcd/issues/8224).
- Fix [`grpc.Server` panic on `GracefulStop`](https://github.com/coreos/etcd/pull/8987) with [TLS-enabled server](https://github.com/coreos/etcd/issues/8916).