etcd/CHANGELOG-3.4.md

v3.4.0 (TBD 2018-05-01)

See code changes and v3.4 upgrade guide for any breaking changes.

Improved

• Add jitter to watch progress notify to prevent spikes in etcd_network_client_grpc_sent_bytes_total.
• Add warnings on requests taking too long.
  • e.g. etcdserver: read-only range request "key:\"\\000\" range_end:\"\\000\" " took too long [3.389041388s] to execute
• Improve long-running concurrent read transactions under light write workloads.
  • Previously, periodic commit on pending writes blocks incoming read transactions, even if there is no pending write.
  • Now, periodic commit operation does not block concurrent read transactions, thus improves long-running read transaction performance.

Changed(Breaking Changes)

• Drop ACIs from official release.
  • AppC was officially suspended, as of late 2016.
  • acbuild is not maintained anymore.
  • *.aci files are not available from v3.4 release.
• Exit on empty hosts in advertise URLs.
  • Address advertise client URLs accepts empty hosts.
  • e.g. exit with error on --advertise-client-urls=http://:2379.
  • e.g. exit with error on --initial-advertise-peer-urls=http://:2380.
• Exit on shadowed environment variables.
  • Address error on shadowed environment variables.
  • e.g. exit with error on ETCD_INITIAL_CLUSTER_TOKEN=abc etcd --initial-cluster-token=def.
• Migrate dependency management tool from glide to golang/dep.
  • <= 3.3 puts vendor directory under cmd/vendor directory to prevent conflicting transitive dependencies.
  • 3.4 moves cmd/vendor directory to vendor at repository root.
  • Remove recursive symlinks in cmd directory.
  • Now go get/install/build on etcd packages (e.g. clientv3, tools/benchmark) enforce builds with etcd vendor directory.
• Reorganize internal packages.
  • internal/* packages cannot be(are not meant to be) imported by external projects.
    • Move "github.com/coreos/etcd/alarm" to "github.com/coreos/etcd/internal/alarm".
    • Move "github.com/coreos/etcd/auth" to "github.com/coreos/etcd/internal/auth".
    • Move "github.com/coreos/etcd/compactor" to "github.com/coreos/etcd/internal/compactor".
      • embed.CompactorModePeriodic to replace compactor.ModePeriodic.
      • embed.CompactorModeRevision to replace compactor.ModeRevision.
    • Move "github.com/coreos/etcd/discovery" to "github.com/coreos/etcd/internal/discovery".
    • Move "github.com/coreos/etcd/lease" to "github.com/coreos/etcd/internal/lease".
    • Move "github.com/coreos/etcd/mvcc" to "github.com/coreos/etcd/internal/mvcc".
    • Move "github.com/coreos/etcd/snap" to "github.com/coreos/etcd/internal/raftsnap".
    • Move "github.com/coreos/etcd/store" to "github.com/coreos/etcd/internal/store".
    • Move "github.com/coreos/etcd/version" to "github.com/coreos/etcd/internal/version".
  • Move "github.com/coreos/etcd/etcdserver/auth" to "github.com/coreos/etcd/etcdserver/v2auth".
  • Change v3 etcdctl snapshot exit codes with snapshot package.
    • Exit on error with exit code 1 (no more exit code 5 or 6 on snapshot save/restore commands).
• Require Go 1.10+.

Added(etcd)

• Add --discovery-srv-name flag to support custom DNS SRV name with discovery.
  • If not given, etcd queries _etcd-server-ssl._tcp.[YOUR_HOST] and _etcd-server._tcp.[YOUR_HOST].
  • If --discovery-srv-name="foo", then query _etcd-server-ssl-foo._tcp.[YOUR_HOST] and _etcd-server-foo._tcp.[YOUR_HOST].
  • Useful for operating multiple etcd clusters under the same domain.

Added(API)

• Add snapshot package for snapshot restore/save operations.
• Add watch_id field to etcdserverpb.WatchCreateRequest, allow user-provided watch ID to mvcc.
  • Corresponding watch_id is returned via etcdserverpb.WatchResponse, if any.
• Add raftAppliedIndex field to etcdserverpb.StatusResponse for current Raft applied index.
• Add errors field to etcdserverpb.StatusResponse for server-side error.
  • e.g. "etcdserver: no leader", "NOSPACE", "CORRUPT"
• Add dbSizeInUse field to etcdserverpb.StatusResponse for actual DB size after compaction.

Added(v3 etcdctl)

• Add check datascale command.
• Add "raft applied index" field to endpoint status.
• Add "errors" field to endpoint status.

Added(metrics)

• Add etcd_debugging_mvcc_db_total_size_in_use_in_bytes Prometheus metric.

Added(gRPC gateway)

• Replace gRPC gateway endpoint with /v3.
  • To deprecate [/v3beta] in v3.5.

Package raft

• Fix deadlock during PreVote migration process.
• Add raft.ErrProposalDropped.
  • Now (r *raft) Step returns raft.ErrProposalDropped if a proposal has been ignored.
  • e.g. a node is removed from cluster, ongoing leadership transfer, etc.
• Improve Raft becomeLeader and stepLeader by keeping track of latest pb.EntryConfChange index.
  • Previously record pendingConf boolean field scanning the entire tail of the log, which can delay hearbeat send.
• Fix missing learner nodes on (n *node) ApplyConfChange.

Fixed(v3)

• Fix mvcc "unsynced" watcher restore operation.
  • "unsynced" watcher is watcher that needs to be in sync with events that have happened.
  • That is, "unsynced" watcher is the slow watcher that was requested on old revision.
  • "unsynced" watcher restore operation was not correctly populating its underlying watcher group.
  • Which possibly causes missing events from "unsynced" watchers.