v4.0.8

KNOWLEDGE BASE

Release Notes v4.0.8

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 v4.0.8.

⚠️ IMPORTANT UPGRADE NOTICE

v4.0.7 JSON pack state was broken. Users must upgrade to v4.0.8 immediately. This release includes critical fixes for JSON tokenizer regressions that affected data processing in v4.0.7.

Below is a detailed list of changes included in this release…

What’s new ?

Core

• pack: fix token count regression in JSON tokenizer and remove parser reset (PR #10740)
• engine: fix endless loop on reload (PR #10709)
• metrics: add flb_metrics_is_empty() helper (PR #10736)
• input_metric: drop metrics with empty data series (PR #10736)
• output
  • discard metrics with empty data series (PR #10736)
  • safe cleanup on metricsprocessors failure (PR #10736)
• opentelemetry: logs: fix trace_id and span_id length packaging (PR #10768)
• dockerfiles: windows: update to ltsc 2025 and fix layers (PR #10764)

Libraries

• chunkio: update to 98988d25 (PR #10763)

Plugins

• Node_exporter_metrics (Input)
  • add Linux sockstat collector (PR #10737)
  • add Linux hwmon collector (PR #10738)
  • add new option path.rootfs (PR #10739)
• Kafka (Input)
  • improve offset commit timing to avoid data loss in edge cases (PR #10741)
• Calyptia_fleet (Input)
  • fleet config fetch ignores older-timestamped files (PR #10762)
• Azure_kusto (Output)
  • Added workload identity support (#10283) (PR #10742)
• Datadog (Output)
  • task_arn now correctly mapped to full arn (PR #10744)
• Cloudwatch (Output)
  • add entity support and remove unnecessary log content (PR #10743)
• Kinesis_firehose (Output)
  • introduce port parameter (PR #10745)
• Elasticsearch (Output)
  • add apikey to available auth types (PR #10765)

Join us

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

• Github: http://github.com/fluent/fluent-bit
• Slack: http://slack.fluentd.org
• Twitter: @fluentbit