v4.0.2

Next generation Telemetry Agent for Logs, Metrics and Traces.

May 13, 2025

KNOWLEDGE BASE

Release Notes v4.0.2

Fluent Bit is a Fast and Lightweight Data Processor and Forwarder for Linux, BSD, Windows and macOS. We are proud to announce the availability of Fluent Bit v4.0.2.


What’s new ?


NOTE: In v4.0 series, we have upgraded our internal dependencies and deprecated packages for older targets like Ubuntu 16.04, 18.04 and 20.04. In addition, due to Kafka library updates, we have disabled Kafka support for CentOS 7 and Amazon Linux 2.

Core


  • pack: add metadata and group info into log JSON record (new __internal__ key). (PR #10282)
  • processor: fail on startup when invalid processors are configured (PR #10306)
  • input: add missing options to input_global_properties. (PR #10281)
  • simd: (RISC-V) Use __riscv_vsetvl_eXXm1 function to get the actual width of RVV instructions (PR #10310)
  • engine
    • added conditional to avoid re-scheduling conflict (PR #10290)
    • Display the current maxstdio value on debug level log (PR #9707)
  • build
    • use the system provided msgpack if found (PR #9572)
    • use the system provided sqlite if found (PR #9572)
    • use the system provided libzstd if found (PR #9572)
    • only compile simdutf if there is CXX support (PR #10277)
  • systemd: build: fix service startup failure when using IMDSv2 (PR #10221)
  • bin:
    • config: Provide maxstdio option for increasing I/O limit on Windows (PR #9707)
  • config
    • Add windows/. prefix into maxstdio parameter (PR #9707)
    • bin: Add prefix for windows specific functuionality (PR #9707)
  • tests
    • internal: fuzzers: split cmetrics decoding (PR #10249)
    • add processor_invalid.sh test for validating invalid processor handling (PR #10306)
    • modify processor config to use a valid one that works on all archs (s390x/riscv64) (PR #10306)

Libraries

Plugins


Contributors

On every release, there are many people involved doing contributions on different areas like bug reporting, troubleshooting, documentation and coding, without these contributions from the community, the project won’t be the same and won’t be in the good shape that it is now. So THANK YOU! to everyone who takes part of this journey!

Join us

We want to hear about you, our community is growing and you can be part of it!, you can contact us at:

Latest Version

New release on May 30, 2025

Fluent Bit v4.0.3 is out!

Check out the Release Notes, read the Updated Documentation or jump directly to the Downloads Section.

We are part of a wide community, no vendor lock-in.