etcd-io__etcd/CHANGELOG-3.3.md

Previous change logs can be found at CHANGELOG-3.2.

v3.3.8 (TBD 2018-06)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

Improved

• Improve slow request apply warning log.
  • e.g. request "header:<ID:7587830746365689092 > put:<key:\"a\" value_size:14 >" took too long (59.798µs) to execute.
  • Redact request value field.

Go

• Compile with Go 1.9.7.

v3.3.7 (2018-06-06)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

Security, Authentication

• Support TLS cipher suite whitelisting.
  • To block weak cipher suites.
  • TLS handshake fails when client hello is requested with invalid cipher suites.
  • Add etcd --cipher-suites flag.
  • If empty, Go auto-populates the list.

etcdctl v3

• Fix etcdctl move-leader command for TLS-enabled endpoints.

Go

• Compile with Go 1.9.6.

v3.3.6 (2018-05-31)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

etcd server

• Allow empty auth token.
  • Previously, when auth token is an empty string, it returns failed to initialize the etcd server: auth: invalid auth options error.
• Fix auth storage panic on server lease revoke routine with JWT token.
• Fix mvcc server panic from restore operation.
  • Let's assume that a watcher had been requested with a future revision X and sent to node A that became network-partitioned thereafter. Meanwhile, cluster makes progress. Then when the partition gets removed, the leader sends a snapshot to node A. Previously if the snapshot's latest revision is still lower than the watch revision X, etcd server panicked during snapshot restore operation.
  • Now, this server-side panic has been fixed.

Go

• Compile with Go 1.9.6.

v3.3.5 (2018-05-09)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

etcdctl v3

• Fix etcdctl watch [key] [range_end] -- [exec-command…] parsing.
  • Previously, ETCDCTL_API=3 ./bin/etcdctl watch foo -- echo watch event received panicked.

Go

• Compile with Go 1.9.6.

v3.3.4 (2018-04-24)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

Metrics, Monitoring

• Add etcd_server_is_leader Prometheus metric.
• Fix etcd_debugging_server_lease_expired_total Prometheus metric.
• Fix race conditions in v2 server stat collecting.

Security, Authentication

• Fix TLS reload when certificate SAN field only includes IP addresses but no domain names.
  • In Go, server calls (*tls.Config).GetCertificate for TLS reload if and only if server's (*tls.Config).Certificates field is not empty, or (*tls.ClientHelloInfo).ServerName is not empty with a valid SNI from the client. Previously, etcd always populates (*tls.Config).Certificates on the initial client TLS handshake, as non-empty. Thus, client was always expected to supply a matching SNI in order to pass the TLS verification and to trigger (*tls.Config).GetCertificate to reload TLS assets.
  • However, a certificate whose SAN field does not include any domain names but only IP addresses would request *tls.ClientHelloInfo with an empty ServerName field, thus failing to trigger the TLS reload on initial TLS handshake; this becomes a problem when expired certificates need to be replaced online.
  • Now, (*tls.Config).Certificates is created empty on initial TLS client handshake, first to trigger (*tls.Config).GetCertificate, and then to populate rest of the certificates on every new TLS connection, even when client SNI is empty (e.g. cert only includes IPs).

etcd server

• Add etcd --initial-election-tick-advance flag to configure initial election tick fast-forward.
  • By default, etcd --initial-election-tick-advance=true, then local member fast-forwards election ticks to speed up "initial" leader election trigger.
  • This benefits the case of larger election ticks. For instance, cross datacenter deployment may require longer election timeout of 10-second. If true, local node does not need wait up to 10-second. Instead, forwards its election ticks to 8-second, and have only 2-second left before leader election.
  • Major assumptions are that: cluster has no active leader thus advancing ticks enables faster leader election. Or cluster already has an established leader, and rejoining follower is likely to receive heartbeats from the leader after tick advance and before election timeout.
  • However, when network from leader to rejoining follower is congested, and the follower does not receive leader heartbeat within left election ticks, disruptive election has to happen thus affecting cluster availabilities.
  • Now, this can be disabled by setting --initial-election-tick-advance=false.
  • Disabling this would slow down initial bootstrap process for cross datacenter deployments. Make tradeoffs by configuring etcd --initial-election-tick-advance at the cost of slow initial bootstrap.
  • If single-node, it advances ticks regardless.
  • Address disruptive rejoining follower node.

Package embed

• Add embed.Config.InitialElectionTickAdvance to enable/disable initial election tick fast-forward.
  • embed.NewConfig() would return *embed.Config with InitialElectionTickAdvance as true by default.

Go

• Compile with Go 1.9.5.

v3.3.3 (2018-03-29)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

Improved

• Adjust election timeout on server restart to reduce disruptive rejoining servers.
  • Previously, etcd fast-forwards election ticks on server start, with only one tick left for leader election. This is to speed up start phase, without having to wait until all election ticks elapse. Advancing election ticks is useful for cross datacenter deployments with larger election timeouts. However, it was affecting cluster availability if the last tick elapses before leader contacts the restarted node.
  • Now, when etcd restarts, it adjusts election ticks with more than one tick left, thus more time for leader to prevent disruptive restart.
• Adjust periodic compaction retention window.
  • e.g. etcd --auto-compaction-mode=revision --auto-compaction-retention=1000 automatically Compact on "latest revision" - 1000 every 5-minute (when latest revision is 30000, compact on revision 29000).
  • e.g. Previously, etcd --auto-compaction-mode=periodic --auto-compaction-retention=72h automatically Compact with 72-hour retention windown for every 7.2-hour. Now, Compact happens, for every 1-hour but still with 72-hour retention window.
  • e.g. Previously, etcd --auto-compaction-mode=periodic --auto-compaction-retention=30m automatically Compact with 30-minute retention windown for every 3-minute. Now, Compact happens, for every 30-minute but still with 30-minute retention window.
  • Periodic compactor keeps recording latest revisions for every compaction period when given period is less than 1-hour, or for every 1-hour when given compaction period is greater than 1-hour (e.g. 1-hour when etcd --auto-compaction-mode=periodic --auto-compaction-retention=24h).
  • For every compaction period or 1-hour, compactor uses the last revision that was fetched before compaction period, to discard historical data.
  • The retention window of compaction period moves for every given compaction period or hour.
  • For instance, when hourly writes are 100 and etcd --auto-compaction-mode=periodic --auto-compaction-retention=24h, v3.2.x, v3.3.0, v3.3.1, and v3.3.2 compact revision 2400, 2640, and 2880 for every 2.4-hour, while v3.3.3 or later compacts revision 2400, 2500, 2600 for every 1-hour.
  • Futhermore, when etcd --auto-compaction-mode=periodic --auto-compaction-retention=30m and writes per minute are about 1000, v3.3.0, v3.3.1, and v3.3.2 compact revision 30000, 33000, and 36000, for every 3-minute, while v3.3.3 or later compacts revision 30000, 60000, and 90000, for every 30-minute.

Metrics, Monitoring

• Add missing etcd_network_peer_sent_failures_total count.

Go

• Compile with Go 1.9.5.

v3.3.2 (2018-03-08)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

etcd server

• Fix server panic on invalid Election Proclaim/Resign HTTP(S) requests.
  • Previously, wrong-formatted HTTP requests to Election API could trigger panic in etcd server.
  • e.g. curl -L http://localhost:2379/v3/election/proclaim -X POST -d '{"value":""}', curl -L http://localhost:2379/v3/election/resign -X POST -d '{"value":""}'.
• Fix revision-based compaction retention parsing.
  • Previously, etcd --auto-compaction-mode revision --auto-compaction-retention 1 was translated to revision retention 3600000000000.
  • Now, etcd --auto-compaction-mode revision --auto-compaction-retention 1 is correctly parsed as revision retention 1.
• Prevent overflow by large TTL values for Lease Grant.
  • TTL parameter to Grant request is unit of second.
  • Leases with too large TTL values exceeding math.MaxInt64 expire in unexpected ways.
  • Server now returns rpctypes.ErrLeaseTTLTooLarge to client, when the requested TTL is larger than 9,000,000,000 seconds (which is >285 years).
  • Again, etcd Lease is meant for short-periodic keepalives or sessions, in the range of seconds or minutes. Not for hours or days!
• Enable etcd server raft.Config.CheckQuorum when starting with ForceNewCluster.

Proxy v2

• Fix v2 proxy leaky HTTP requests.

Go

• Compile with Go 1.9.4.

v3.3.1 (2018-02-12)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

Improved

• 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

etcd server

• 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.
  • A node gets network partitioned with a watcher on a future revision, and falls behind receiving a leader snapshot after partition gets removed. When applying this snapshot, etcd watch storage moves current synced watchers to unsynced since sync watchers might have become stale during network partition. And reset synced watcher group to restart watcher routines. Previously, there was a bug when moving from synced watcher group to unsynced, thus client would miss events when the watcher was requested to the network-partitioned node.

Go

• Compile with Go 1.9.4.

v3.3.0 (2018-02-01)

See code changes and v3.3 upgrade guide for any breaking changes. Again, before running upgrades from any previous release, please make sure to read change logs below and v3.3 upgrade guide.

• v3.3.0-rc.4 (2018-01-22), see code changes.
• v3.3.0-rc.3 (2018-01-17), see code changes.
• v3.3.0-rc.2 (2018-01-11), see code changes.
• v3.3.0-rc.1 (2018-01-02), see code changes.
• v3.3.0-rc.0 (2017-12-20), see code changes.

Improved

• Use coreos/bbolt to replace boltdb/bolt.
  • Fix etcd database size grows until mvcc: database space exceeded.
• Support database size larger than 8GiB (8GiB is now a suggested maximum size for normal environments)
• Reduce memory allocation on Range operations.
• Rate limit and randomize lease revoke on restart or leader elections.
  • Prevent spikes in Raft proposal rate.
• Support clientv3 balancer failover under network faults/partitions.
• Better warning on mismatched etcd --initial-cluster flag.
  • etcd compares etcd --initial-advertise-peer-urls against corresponding etcd --initial-cluster URLs with forward-lookup.
  • If resolved IP addresses of etcd --initial-advertise-peer-urls and etcd --initial-cluster do not match (e.g. due to DNS error), etcd will exit with errors.
  • v3.2 error: etcd --initial-cluster must include s1=https://s1.test:2380 given --initial-advertise-peer-urls=https://s1.test:2380.
  • v3.3 error: failed to resolve https://s1.test:2380 to match --initial-cluster=s1=https://s1.test:2380 (failed to resolve "https://s1.test:2380" (error ...)).

Breaking Changes

• Require google.golang.org/grpc v1.7.4 or v1.7.5.
  • Deprecate metadata.Incoming/OutgoingContext.
  • Deprecate grpclog.Logger, upgrade to grpclog.LoggerV2.
  • Deprecate grpc.ErrClientConnTimeout errors in clientv3.
  • Use MaxRecvMsgSize and MaxSendMsgSize to limit message size, in etcd server.
• Translate gRPC status error in v3 client Snapshot API.
• v3 etcdctl lease timetolive LEASE_ID on expired lease now prints "lease LEASE_ID already expired".
  • <=3.2 prints "lease LEASE_ID granted with TTL(0s), remaining(-1s)".
• Replace gRPC gateway endpoint /v3alpha with /v3beta.
  • To deprecate /v3alpha in v3.4.
  • In v3.3, curl -L http://localhost:2379/v3alpha/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' still works as a fallback to curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}', but curl -L http://localhost:2379/v3alpha/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' won't work in v3.4. Use curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' instead.
• Change etcd --auto-compaction-retention flag to accept string values with finer granularity.
  • Now that etcd --auto-compaction-retention accepts string values, etcd configuration YAML file auto-compaction-retention field must be changed to string type.
  • Previously, --config-file etcd.config.yaml can have auto-compaction-retention: 24 field, now must be auto-compaction-retention: "24" or auto-compaction-retention: "24h".
  • If configured as etcd --auto-compaction-mode periodic --auto-compaction-retention "24h", the time duration value for etcd --auto-compaction-retention flag must be valid for time.ParseDuration function in Go.

Dependency

• Upgrade boltdb/bolt from v1.3.0 to coreos/bbolt v1.3.1-coreos.6.
• Upgrade google.golang.org/grpc from v1.2.1 to v1.7.5.
• Upgrade github.com/ugorji/go/codec to v1.1, and regenerate v2 client.
• Upgrade github.com/ugorji/go/codec to ugorji/go@54210f4e0, and regenerate v2 client.
• Upgrade github.com/grpc-ecosystem/grpc-gateway from v1.2.2 to v1.3.0.
• Upgrade golang.org/x/crypto/bcrypt to golang/crypto@6c586e17d.

Metrics, Monitoring

• Add etcd --listen-metrics-urls flag for additional /metrics and /health endpoints.
  • Useful for bypassing critical APIs when monitoring etcd.
• Add etcd_server_version Prometheus metric.
  • To replace Kubernetes etcd-version-monitor.
• Add etcd_debugging_mvcc_db_compaction_keys_total Prometheus metric.
• Add etcd_debugging_server_lease_expired_total Prometheus metric.
  • To improve lease revoke monitoring.
• Document Prometheus 2.0 rules.
• Initialize gRPC server metrics with zero values.
• Fix range/put/delete operation metrics with transaction.
  • etcd_debugging_mvcc_range_total
  • etcd_debugging_mvcc_put_total
  • etcd_debugging_mvcc_delete_total
  • etcd_debugging_mvcc_txn_total
• Fix etcd_debugging_mvcc_keys_total on restore.
• Fix etcd_debugging_mvcc_db_total_size_in_bytes on restore.
  • Also change to prometheus.NewGaugeFunc.

Security, Authentication

See security doc for more details.

• Add CRL based connection rejection to manage revoked certs.
• Document TLS authentication changes.
  • Server accepts connections if IP matches, without checking DNS entries. 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. 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.
• Add etcd --peer-cert-allowed-cn flag.
  • To support CommonName(CN) based auth for inter peer connection.
• Swap priority of cert CommonName(CN) and username + password.
  • To address "username and password specified in the request should take priority over CN in the cert".
• Protect lease revoke with auth.
• Provide user's role on auth permission error.
• Fix auth store panic with disabled token.

etcd server

• Add etcd --experimental-initial-corrupt-check flag to check cluster database hashes before serving client/peer traffic.
  • etcd --experimental-initial-corrupt-check=false by default.
  • v3.4 will enable --initial-corrupt-check=true by default.
• Add etcd --experimental-corrupt-check-time flag to raise corrupt alarm monitoring.
  • etcd --experimental-corrupt-check-time=0s disabled by default.
• Add etcd --experimental-enable-v2v3 flag to emulate v2 API with v3.
  • etcd --experimental-enable-v2v3=false by default.
• Add etcd --max-txn-ops flag to configure maximum number operations in transaction.
• Add etcd --max-request-bytes flag to configure maximum client request size.
  • If not configured, it defaults to 1.5 MiB.
• Add etcd --client-crl-file, --peer-crl-file flags for Certificate revocation list.
• Add etcd --peer-cert-allowed-cn flag to support CN-based auth for inter-peer connection.
• Add etcd --listen-metrics-urls flag for additional /metrics and /health endpoints.
  • Support additional (non) TLS /metrics endpoints for a TLS-enabled cluster.
  • e.g. etcd --listen-metrics-urls=https://localhost:2378,http://localhost:9379 to serve /metrics and /health on secure port 2378 and insecure port 9379.
  • Useful for bypassing critical APIs when monitoring etcd.
• Add etcd --auto-compaction-mode flag to support revision-based compaction.
• Change etcd --auto-compaction-retention flag to accept string values with finer granularity.
  • Now that etcd --auto-compaction-retention accepts string values, etcd configuration YAML file auto-compaction-retention field must be changed to string type.
  • Previously, etcd --config-file etcd.config.yaml can have auto-compaction-retention: 24 field, now must be auto-compaction-retention: "24" or auto-compaction-retention: "24h".
  • If configured as --auto-compaction-mode periodic --auto-compaction-retention "24h", the time duration value for etcd --auto-compaction-retention flag must be valid for time.ParseDuration function in Go.
  • e.g. etcd --auto-compaction-mode=revision --auto-compaction-retention=1000 automatically Compact on "latest revision" - 1000 every 5-minute (when latest revision is 30000, compact on revision 29000).
  • e.g. etcd --auto-compaction-mode=periodic --auto-compaction-retention=72h automatically Compact with 72-hour retention windown, for every 7.2-hour.
  • e.g. etcd --auto-compaction-mode=periodic --auto-compaction-retention=30m automatically Compact with 30-minute retention windown, for every 3-minute.
  • Periodic compactor continues to record latest revisions for every 1/10 of given compaction period (e.g. 1-hour when etcd --auto-compaction-mode=periodic --auto-compaction-retention=10h).
  • For every 1/10 of given compaction period, compactor uses the last revision that was fetched before compaction period, to discard historical data.
  • The retention window of compaction period moves for every 1/10 of given compaction period.
  • For instance, when hourly writes are 100 and --auto-compaction-retention=10, v3.1 compacts revision 1000, 2000, and 3000 for every 10-hour, while v3.2.x, v3.3.0, v3.3.1, and v3.3.2 compact revision 1000, 1100, and 1200 for every 1-hour. Futhermore, when writes per minute are 1000, v3.3.0, v3.3.1, and v3.3.2 with --auto-compaction-mode=periodic --auto-compaction-retention=30m compact revision 30000, 33000, and 36000, for every 3-minute with more finer granularity.
  • Whether compaction succeeds or not, this process repeats for every 1/10 of given compaction period. If compaction succeeds, it just removes compacted revision from historical revision records.
• Add etcd --grpc-keepalive-min-time, etcd --grpc-keepalive-interval, etcd --grpc-keepalive-timeout flags to configure server-side keepalive policies.
• Serve /health endpoint as unhealthy when alarm (e.g. NOSPACE) is raised or there's no leader.
  • Define etcdhttp.Health struct with JSON encoder.
  • Note that "health" field is string type, not bool.
  • e.g. {"health":"false"}, {"health":"true"}
  • Remove "errors" field 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).
• Move logging setup to embed package
  • Disable gRPC server info-level logs by default (can be enabled with etcd --debug flag).
• Use monotonic time in Go 1.9 for lease package.
• Warn on empty hosts in advertise URLs.
  • Address advertise client URLs accepts empty hosts.
  • etcd v3.4 will exit on this error.
  • e.g. etcd --advertise-client-urls=http://:2379.
• Warn on shadowed environment variables.
  • Address error on shadowed environment variables.
  • etcd v3.4 will exit on this error.

API

• Support ranges in transaction comparisons for disconnected linearized reads.
• Add nested transactions to extend proxy use cases.
• Add lease comparison target in transaction.
• Add lease list.
• Add hash by revision for better corruption checking against boltdb.

client v3

• Add health balancer to fix watch API hangs, improve endpoint switch under network faults.
• Refactor balancer and add client-side keepalive pings to handle network partitions.
• Add MaxCallSendMsgSize and MaxCallRecvMsgSize fields to clientv3.Config.
  • Fix exceeded response size limit error in client-side.
  • Address kubernetes#51099.
  • 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 in clientv3.Compare.
• Add LeaseValue helper to Cmp LeaseID values in Txn.
• Add MoveLeader to Maintenance.
• Add HashKV to Maintenance.
• Add Leases to Lease.
• Add clientv3/ordering for enforce ordering in serialized requests.
• Fix "put at-most-once" violation.
• Fix WatchResponse.Canceled on compacted watch request.
• Fix concurrency/stm Put with serializable snapshot.
  • Use store revision from first fetch to resolve write conflicts instead of modified revision.

etcdctl v3

• Add etcdctl --discovery-srv flag.
• Add etcdctl --keepalive-time, --keepalive-timeout flags.
• Add etcdctl lease list command.
• Add etcdctl lease keep-alive --once flag.
• Make lease timetolive LEASE_ID on expired lease print lease LEASE_ID already expired.
  • <=3.2 prints lease LEASE_ID granted with TTL(0s), remaining(-1s).
• Add etcdctl snapshot restore --wal-dir flag.
• Add etcdctl defrag --data-dir flag.
• Add etcdctl move-leader command.
• Add etcdctl endpoint hashkv command.
• Add etcdctl endpoint --cluster flag, equivalent to v2 etcdctl cluster-health.
• Make etcdctl endpoint health command terminate with non-zero exit code on unhealthy status.
• Add etcdctl lock --ttl flag.
• Support etcdctl watch [key] [range_end] -- [exec-command…], equivalent to v2 etcdctl exec-watch.
  • Make etcdctl watch -- [exec-command] set environmental variables ETCD_WATCH_REVISION, ETCD_WATCH_EVENT_TYPE, ETCD_WATCH_KEY, ETCD_WATCH_VALUE for each event.
• Support etcdctl watch with environmental variables ETCDCTL_WATCH_KEY and ETCDCTL_WATCH_RANGE_END.
• Enable clientv3.WithRequireLeader(context.Context) for watch command.
• Print "del" instead of "delete" in txn interactive mode.
• Print ETCD_INITIAL_ADVERTISE_PEER_URLS in member add.

etcdctl v3

• Handle empty key permission in etcdctl.

etcdctl v2

• Add etcdctl backup --with-v3 flag.

gRPC Proxy

• Add grpc-proxy start --experimental-leasing-prefix flag.
  • For disconnected linearized reads.
  • Based on V system leasing.
  • See "Disconnected consistent reads with etcd" blog post.
• Add grpc-proxy start --experimental-serializable-ordering flag.
  • To ensure serializable reads have monotonically increasing store revisions across endpoints.
• Add grpc-proxy start --metrics-addr flag for an additional /metrics endpoint.
  • Set --metrics-addr=http://[HOST]:9379 to serve /metrics in insecure port 9379.
• Serve /health endpoint in grpc-proxy.
• Add grpc-proxy start --debug flag.
• Add grpc-proxy start --max-send-bytes flag to configure maximum client request size.
• Add grpc-proxy start --max-recv-bytes flag to configure maximum client request size.
• Fix Snapshot API error handling.
• Fix KV API PrevKv flag handling.
• Fix KV API KeysOnly flag handling.

gRPC gateway

• Replace gRPC gateway endpoint /v3alpha with /v3beta.
  • To deprecate /v3alpha in v3.4.
  • In v3.3, curl -L http://localhost:2379/v3alpha/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' still works as a fallback to curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}', but curl -L http://localhost:2379/v3alpha/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' won't work in v3.4. Use curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}' instead.
• Support "authorization" token.
• Support websocket for bi-directional streams.
  • Fix Watch API with gRPC gateway.
• Upgrade gRPC gateway to v1.3.0.

etcd server

• Fix backend database in-memory index corruption issue on restore (only 3.2.0 is affected).
• Fix watch restore from snapshot.
• Fix mvcc/backend.defragdb nil-pointer dereference on create bucket failure.
• Fix server crash on invalid transaction request from gRPC gateway.
• Prevent server panic from member update/add with wrong scheme URLs.
• Make peer dial timeout longer.
  • See coreos/etcd-operator#1300 for more detail.
• Make server wait up to request time-out with pending RPCs.
• Fix grpc.Server panic on GracefulStop with TLS-enabled server.
• Fix "multiple peer URLs cannot start" issue.
• Fix server-side auth so concurrent auth operations do not return old revision error.
• Handle WAL renaming failure on Windows.
• Upgrade coreos/go-systemd to v15 (see https://github.com/coreos/go-systemd/releases/tag/v15).
• Put back /v2/machines endpoint for python-etcd wrapper.

client v2

• Fail-over v2 client to next endpoint on oneshot failure.

Package raft

• Add non-voting member.
  • To implement Raft thesis 4.2.1 Catching up new servers.
  • Learner node does not vote or promote itself.

Other

• Support previous two minor versions (see our new release policy).
• v3.3.x is the last release cycle that supports ACI.
  • AppC was officially suspended, as of late 2016.
  • acbuild is not maintained anymore.
  • *.aci files won't be available from etcd v3.4 release.
• Add container registry gcr.io/etcd-development/etcd.
  • quay.io/coreos/etcd is still supported as secondary.

Go

• Require Go 1.9+.
• Compile with Go 1.9.3.
• Deprecate golang.org/x/net/context.