v5.0.6

KNOWLEDGE BASE

Release Notes v5.0.6

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 v5.0.6.

This maintenance release adds more control for durable storage and OTLP delivery, improves HTTP server and Tail input reliability, expands package coverage for Ubuntu 26.04, and tightens shutdown, TLS, cloud output, and allocation-failure handling across production pipelines.

What’s new ?

Core

• config: add bash-style ${name:-word} default expansion for environment variables, making shared configuration files easier to run across environments with optional values
• storage: add storage.rejected.limit to cap the total size used by rejected chunks in the dead-letter queue and warn before the limit is reached
• http_server: improve internal monitoring server responsiveness by running it on a worker thread, protecting shared metrics buffers, and cleaning up stalled or dropped client sessions more reliably
• http_server: add http_server.idle_timeout so HTTP based inputs and exporters can evict idle accepted connections and recover capacity under partial or stalled requests
• tls: handle IP literal hosts without sending TLS SNI and validate IP literals through the appropriate certificate checks
• engine: ignore duplicate shutdown stop signals once shutdown is in progress, preventing a shutdown spin and improving process termination reliability
• packaging: add Ubuntu 26.04 package build targets for amd64 and arm64
• tests: expand internal, runtime, and integration coverage for HTTP server idle recovery, internal monitoring self-requests, TLS SNI IP literals, Tail truncation, Kafka OTLP resource partitioning, Forward allocation failures, shutdown behavior, DLQ limits, and environment variable defaults

Libraries

• cfl: upgrade the bundled library to v0.7.1 with expanded container, atomic, checksum, SDS, kvlist, object, and variant coverage
• cmetrics: upgrade the bundled library to v2.1.4 with improved Prometheus decoder error handling and allocation-failure cleanup

Plugins

• Kafka (Output)
  • add otlp_logs_partition_by_resource for otlp_json and otlp_proto formats, allowing OTLP log batches to be split by resource and keyed consistently for Kafka partitioning
  • improve cleanup for dynamic topic handling
• Tail (Input)
  • reconcile tailed files after missed inotify events so pending data, truncation, deletion, and rotation state are recovered more reliably
  • improve cleanup when file registration fails during startup or file promotion
• Forward (Input)
  • handle MessagePack unpacker allocation failures cleanly
• Elasticsearch (Input)
  • improve bulk API response handling when status buffers need to grow or cannot be appended
• Node Exporter Metrics (Input)
  • improve Linux meminfo metric handling on allocation failures
• OpenTelemetry (Output)
  • clean up request state when HTTP authorization setup fails
• Prometheus Exporter (Output)
  • apply HTTP server idle timeout handling to exporter connections
• Vivo Exporter (Output)
  • apply HTTP server idle timeout handling to exporter connections
• Azure Logs Ingestion (Output)
  • improve shutdown cleanup when the plugin exits before a full context is available
• Azure (Output)
  • improve request header and configuration string handling on allocation failures
• Azure Kusto (Output)
  • improve request body and workload identity request handling on allocation failures
• BigQuery (Output)
  • improve JWT construction cleanup on allocation or encoding failures
• Stackdriver (Output)
  • improve metadata, label, tag prefix, and JWT construction handling on allocation failures

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: CNCF Slack, channel #fluent-bit (https://communityinviter.com/apps/cloud-native/cncf)
• Twitter: @fluentbit