# Fluent Bit v5.1.2 — Fluent Bit 5.1.2

- Product: Fluent Bit (https://whatsnew.fyi/product/fluent-bit)
- Vendor: Fluent
- Date: 2026-09-05
- Version: v5.1.2
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.1.2
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.1.2

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — Implement stat and thermal_zone for macOS in in_node_exporter_metrics
- **added** — Add time_key support for the HEC event time in out_splunk
- **added** — Add unify_tag option to buffer all tags into one file in out_gcs
- **added** — Implement parquet compressions in out_gcs
- **added** — Support application default credentials in out_gcs
- **added** — Implement namespace exclude in filter_kubernetes
- **added** — Support capturing with namespace in in_systemd
- **added** — Add Workload Identity Federation support in out_gcs
- **added** — Add built-in json parser for JSON multiline objects in multiline
- **added** — Support metrics max datapoints in out_opentelemetry
- **added** — Ingest all metrics contexts in payload in in_forward
- **changed** — Add 1-hour cut-off for expiring staled metrics in out_prometheus_remote_write
- **changed** — Update cmetrics to v2.2.2
- **changed** — Build wamrc with LLVM-17
- **changed** — Expire metrics for networking in in_node_exporter_metrics
- **fixed** — Fix startup abort when log_level set via env and config
- **fixed** — Plug a SEGV occurrence on macOS in runtime tests
- **fixed** — Clamp the suppression length to what was written in log
- **fixed** — Plug a crash path in in_winevtlog
- **fixed** — Fix crash when all channels are missing and ignore_missing_channels is enabled in in_winevtlog
- **fixed** — Handle partial succeeded requests in opensearch output task
- **fixed** — Address underflowing or overflowing chunk limit size in input_chunk
- **fixed** — Plug dangling pointers on exceptions in out_azure_blob
- **fixed** — Stop logging federated and access tokens in out_azure_kusto
- **fixed** — Clean up orphaned chunks in out_s3
- **fixed** — Address wrongly specified parameter on service section in config_format
- **fixed** — Validate valid columnar formats in aws compression
- **fixed** — Plug a race on starting engine
- **fixed** — Preserve configuration path during hot reload
- **fixed** — Scope remove_mpa thread-local cache per instance in out_loki

https://fluentbit.io/announcements/v5.1.2/

##### What's Changed
* workflows: bump docker/setup-buildx-action from 4.2.0 to 4.3.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12311
* workflows: bump reviewdog/action-actionlint from 1.73.1 to 1.73.2 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12301
* workflows: bump github/codeql-action/upload-sarif from 4.37.6 to 4.37.7 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12300
* workflows: bump uraimo/run-on-arch-action from 3.1.0 to 3.2.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12319
* workflows: bump github/codeql-action/upload-sarif from 4.37.7 to 4.37.8 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12324
* in_node_exporter_metrics: Implement stat and thermal_zone for macOS by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12335
* out_prometheus_remote_write: Add 1-hour cut-off for expiring staled metrics by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12334
* out_splunk: add time_key support for the HEC event time by @agup006 in https://github.com/fluent/fluent-bit/pull/12328
* Dockerfile: optimize layers by @marcofranssen in https://github.com/fluent/fluent-bit/pull/10103
* config: fix startup abort when log_level set via env and config by @saisree1217 in https://github.com/fluent/fluent-bit/pull/12316
* tests: runtime: Plug a SEGV occurrence on macOS by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12293
* out_gcs: add unify_tag option to buffer all tags into one file by @uristernik in https://github.com/fluent/fluent-bit/pull/12339
* log: clamp the suppression length to what was written by @arpitjain099 in https://github.com/fluent/fluent-bit/pull/12349
* out_gcs: implement parquet compressions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12303
* out_gcs: support application default credentials by @balys in https://github.com/fluent/fluent-bit/pull/12263
* in_winevtlog: Plug a crash path by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12320
* in_winevtlog: fix crash when all channels are missing and ignore_missing_channels is enabled by @lecaros in https://github.com/fluent/fluent-bit/pull/12318
* log: make consistency for suppress log feature by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12325
* es: opensearch: output: task: handle partial succeeded requests by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12321
* tests: runtime: Fix errors of incompatible types for in_ebpf tests by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12337
* filter_kubernetes: implement namespace exclude by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12312
* in_systemd: support capturing with namespace by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12308
* release: update to 5.1.2 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/12294
* workflows: bump softprops/action-gh-release from 3.0.2 to 3.0.3 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12355
* workflows: bump github/codeql-action/upload-sarif from 4.37.8 to 4.37.9 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12350
* lib: cmetrics: update to v2.2.2 by @edsiper in https://github.com/fluent/fluent-bit/pull/12354
* input_chunk: input_log: in_storage_backlog: address underflowing / overflowing chunk limit size by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12299
* out_azure_blob: Plug dangling pointers on exceptions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12305
* out_azure_kusto: stop logging federated and access tokens by @tanmaya-panda1 in https://github.com/fluent/fluent-bit/pull/12224
* out_gcs: add Workload Identity Federation support by @uristernik in https://github.com/fluent/fluent-bit/pull/12326
* wamrc: Build with LLVM-17 by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12338
* reload: preserve configuration path during hot

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