bookkeeper release-4.18.0

Release 4.18.0 is a major feature release. It introduces structured logging across the whole code base (BP-69), migrates the wire protocol serialization to LightProto and the native I/O library to Rust, and raises the minimum required Java version to 17. It also includes many improvements, bug fixes and dependency/CVE updates.

Apache BookKeeper users are encouraged to upgrade to 4.18.0. Please review the breaking changes and known issues below before upgrading.

Highlights

Structured logging (BP-69) — All BookKeeper logging has been converted from SLF4J format strings to slog, a structured logging API where each event carries typed key/value attributes (e.g. ledgerId, entryId). Logger context is propagated through client operations, so all events related to the same ledger are automatically tagged. Attributes are rendered by log4j2 in both plain-text and JSON output, with an example configuration for OpenTelemetry-compatible JSON logs. PR #4751, #4754, #4755, #4756, #4757, #4758, #4765, #4766, #4767, #4770
LightProto serialization — The BookKeeper wire protocol, metadata formats and stream storage protos have been migrated from protobuf-java to LightProto, which parses and serializes directly on Netty buffers with no intermediate allocations, reducing GC pressure on the hot path. PR #4779, #4780, #4781, #4783
Native I/O library rewritten in Rust — The native-io library used for direct I/O on the bookie has been migrated from C to Rust. PR #4738
Java 17 baseline — Java 17 or later is now required to build and run BookKeeper. PR #4446
Bookie decommission cleans up the cookie (BP-68) — The decommission admin API now deletes the bookie cookie from the metadata store, so a decommissioned bookie id can be reused without manual cleanup. PR #4500, #4592
ZooKeeper read throttling during re-replication (BP-66) — Re-replication can now throttle its ZooKeeper reads, protecting the metadata store from read storms when many ledgers are being recovered. PR #4258
Batch reads of unconfirmed entries (BP-62) — batchReadUnconfirmedAsync is now exposed on ReadHandle. PR #4739

Breaking Changes

Java 17+ is required for building and running BookKeeper (previously Java 11) PR #4446
The default value of readOnlyModeOnAnyDiskFullEnabled changed to true: a bookie now transitions to read-only as soon as any ledger disk is full, instead of only when all disks are full. Set it back to false to restore the previous behavior. PR #4520
The bookkeeper-slogger module has been removed, superseded by the slog structured logging API (BP-69) PR #4764
Removed the deprecated, misspelled method setAllocatorPoolingConcurrenncy — use setAllocatorPoolingConcurrency instead PR #4431
Removed the deprecated class MathUtils PR #4274

Known Issues

PR #4730 (read thread blocking fix in sendResponseAndWait), included in this release, was found to potentially cause a deadlock on the bookie read path. It has been reverted in PR #4830, which will be part of 4.18.1.

Features

Support TCP keep-alive configuration for the bookie server PR #4762
New client API to check whether the BookKeeper client is connected to the metadata service PR #4342
Migrate from Yahoo DataSketches to Apache DataSketches 7.0.1 (KLL) PR #4774
Allow configuring log4j2 AsyncLogger PR #4269

Improvements

Bookie

Add total_entry_log_space_bytes metric PR #4507
Enrich GC metrics to better analyze GC behavior and the time spent in each phase PR #4384
Add metric for RocksDB getLastEntryInLedger to help identify bottlenecks PR #4529
Set ThreadFactory for the Executor in EntryLoggerAllocator PR #4562
Add temp dir property for the native library PR #4533
Apply the WRITE_BUFFER_WATER_MARK setting to child channels in the bookie Netty server PR #4337
Skip wasted optimistic cache insertion in SingleDirectoryDbLedgerStorage when the write lock is held PR #4306
Log only overridden configuration settings at BookieServer startup PR #4768
Remove unused journal time tracking PR #4006

Client

Eliminate unnecessary synchronization on LedgerHandle.getLength() PR #4516
Optimize bounded batch reads by predicting the entry count PR #4741
Improve host address resolution logic for bookie id PR #4588
Rename the client high-priority thread pool PR #4496

Tools

readledger command reads all entries from a bookie when first and last entry ids are not provided PR #4692
Optimize ListActiveLedgersCommand PR #4602
Improve bookie CLI usage information for the --help option PR #4241

Bug Fixes

Bookie

Fix bookie startup failure caused by IOException: Recovery log <id> is missing PR #4740
Prevent double flush due to a race condition in SingleDirectoryDbLedgerStorage PR #4305
Fix RocksDB configuration path handling on Windows PR #4407
Fix endless loop in BufferedChannel read PR #4506
Fix ArrayIndexOutOfBoundsException in ConcurrentLongHashMap PR #4771
Add workaround for ZOOKEEPER-3825 (numeric IPs and DNS names resolving to multiple numeric IPs) with Java 17 support PR #4719
Fix async log appender swallowing error logs when the bookie fails to start PR #4475
Fix SingleThreadExecutor to reject new tasks while a drainTo is in progress and the queue is empty PR #4488

Client

Fix batch reads hanging after digest mismatch retries are ignored PR #4789
Fix WriteSet use-after-recycle in sequence reads PR #4788
Fix NPE in PendingAddOp.maybeTimeout() when clientCtx is null after recycling PR #4760
Fix race condition NPE in V3 response handling during timeout check PR #4737
Fix bookie WatchTask getting stuck PR #4481
Fix sanity check in asyncBatchReadEntries PR #4579
Add strict hostname resolution and loopback check for the advertised address PR #4595
Use the instance slog logger in LedgerHandle.batchReadUnconfirmedAsync PR #4782
Change log level to debug for parameter checks in batch read PR #4485

Others

Fix IllegalThreadStateException in ComponentStarter shutdown hook PR #4733
Fix potential jetcd-core shading problem PR #4526
Fix potential class conflict during the jetcd-core-shaded shading process PR #4532
Fix wrong configuration key in getHttpServerTrustStorePassword PR #4301
Fix exception message formatting in RocksdbKVStore PR #4448
Fix permission denied error in the Docker image PR #4464
Fix options for the sanity test command being ignored PR #4691
Fix duplicated ZooKeeper call in DistributedLog getLogSegmentNames PR #4050
Fix the pid check in bookkeeper-daemon.sh start/stop PR #3113

Build, CI and Tests

Introduce /bkbot command to control CI workflow runs via PR comments PR #4673, #4674, #4746
Upgrade website to Docusaurus 3, built with Node 24 PR #4723
Add Java 21 (LTS) compatibility check and Java 21/Windows daily builds PR #4350, #4292
Add typo check to CI and fix existing typos PR #4375
Improve CI caching for old release downloads and Maven artifacts, improve error logs PR #4722
Remove OWASP dependency check from CI PR #4717
Add javadoc support for pom-only shaded modules PR #4787

Dependency updates

Upgrade Netty to 4.2.14.Final, addressing CVEs PR #4744, #4775, #4799
Upgrade Vert.x to 4.5.25 to address CVE-2026-6860 PR #4790
Upgrade Jetty from 9.4.57 to 12.1.7 PR #4710
Upgrade RocksDB to 9.9.3 PR #4580
Upgrade ZooKeeper from 3.9.3 to 3.9.5 PR #4667, #4721
Upgrade protobuf and gRPC to latest versions; scope gRPC dependencies via grpc-bom PR #4716, #4784
Upgrade OpenTelemetry libraries to 1.61.0 / 2.27.0 PR #4773
Upgrade jctools to 4.0.6 (jctools-core-jdk11) PR #4656, #4776
Upgrade Lombok to 1.18.32 for Java 22 support PR #4267
Upgrade BouncyCastle from 1.75 to 1.78, bc-fips from 1.0.2.4 to 1.0.2.5 PR #4295, #4366
Upgrade commons-io from 2.7 to 2.17.0 PR #4509
Use slf4j-bom and log4j-bom in dependencyManagement PR #4346
Remove unused commons-lang dependency PR #4654
Upgrade os-maven-plugin to support RISC-V 64 PR #4515

Details

Full list of changes: https://github.com/apache/bookkeeper/pulls?q=is%3Apr+milestone%3A4.18.0+is%3Aclosed

Source apache/bookkeeper · release-4.18.0 · 2026-06-10 · upstream release

Mirrored verbatim for indexing. All rights belong to the upstream project.

Release notes are published by the upstream project and mirrored here for indexing. All rights belong to their authors.