Fluentd Blog

fluent-package v6.1.0 has been released

Hi users!

We have released fluent-package v6.1.0 on 2026-10-29. Fluent Package is a stable distribution package of Fluentd. (successor of td-agent)

This is a new release of the v6.1 series. Note that this is NOT an LTS version. If you prefer stability, please use the LTS version (v6.0.x) instead.

Fluent Package v6.1.0

Fluent Package v6.1.0 includes the following improvements:

• Updated bundled Fluentd to v1.20.1.
• Updated bundled Ruby to 3.4.12
• Updated most of bundled gems
• Changed to keep compatibility with older RHEL 9.x/10.x (#1087, #1088)
• msi: fix broken link to enterprise services (#1078)
• Drop LTO flags on RHEL 10.x and Ubuntu. Note that hardening flags are kept. (#1101)
• Added experimental support for Windows ARM64 (#1132)
• Stopped bundling nokogiri on Windows, including x86_64.
• Changed the default package repository URL to packages.fluentd.org.

This article explains the changes in Fluent Package v6.1.0.

Changes

Updated bundled Fluentd to v1.20.1.

Unlike v1.19.x, which is bundled in the LTS version, Fluentd v1.20.1 includes not only many bug fixes but also includes new major features.

See the following Fluentd v1.20.0 has been released article in details.

If you want to use the latest features right away, we recommend this version. If you prefer stability, please keep using the LTS version.

Updated bundled Ruby to 3.4.12

Ruby 3.4.12 is a maintenance release. Compared to Ruby 3.4.5 which was bundled in the previous version (v6.0.0), it includes the following security fixes in bundled gems:

• uri: CVE-2025-61594 (fixed in Ruby 3.4.7)
• rexml: CVE-2025-58767 (fixed in Ruby 3.4.8)
• zlib: CVE-2026-27820 (fixed in Ruby 3.4.9)
• net-imap: CVE-2026-47240, CVE-2026-47241, CVE-2026-47242 (fixed in Ruby 3.4.10)
• resolv: CVE-2026-80212 and CVE-2026-80213 (fixed in Ruby 3.4.11)

For details, please see the Ruby 3.4.7, Ruby 3.4.8, Ruby 3.4.9, Ruby 3.4.10, Ruby 3.4.11 and Ruby 3.4.12 release notes.

Added experimental support for Windows ARM64

We have started providing an experimental Windows ARM64 installer in preparation for the upcoming v7 release.

Stopped bundling nokogiri on Windows

Windows packages no longer bundle nokogiri. This change also applies to x86_64 packages.

When nokogiri is not installed, the winevt_xml parser uses REXML, and in_windows_eventlog2 performs less strict bookmark validation.

To retain the previous behavior or use parser nokogiri, install nokogiri with fluent-gem install nokogiri.

msi: fixed a broken link to enterprise services on popup window

The link to the enterprise services page on the popup window of the Windows installer was broken. It has been fixed in this release. (#1079)

rpm: keep compatibility with older RHEL 9.x and 10.x

Recent build environments introduced dependencies on library symbols unavailable in older RHEL minor releases.

We now build the RHEL 9 and 10 packages using AlmaLinux 9.2 and 10.0 environments, respectively, with key build dependencies pinned to preserve ABI compatibility. (#1087, #1088)

This issue was fixed and shipped as 6.0.4-2 on above platforms which had been implemented in advance, has now been officially released.

rpm deb: disable LTO for RHEL 10 and Ubuntu

RPM 4.19 (AlmaLinux 10) and dpkg-buildflags on Ubuntu export LTO (Link Time Optimization) flags (-flto=auto -ffat-lto-objects) into the build process. These flags leaked into jemalloc, Ruby and native gem extensions, and made the build much slower. For example, the total build time on AlmaLinux 10 grew extraordinaly.

Since the bundled Ruby uses its own optimization settings, LTO gives no measurable benefit here. So we removed the LTO flags and the annobin plugin from the build environment. The hardening flags such as stack protection, control flow protection and FORTIFY_SOURCE are kept as before.

This change also means that native extensions which users build with fluent-gem install no longer inherit the LTO overhead. (#1102)

Package repository requests now go through packages.fluentd.org

The default package repository URL has changed from fluentd.cdn.cncf.io to packages.fluentd.org. Requests now pass through Scarf before being redirected to the existing CDN at fluentd.cdn.cncf.io.

We use statistics on requests for packages and repository metadata to understand usage trends across distributions, versions and architectures. This helps us decide which platforms to prioritize and when to end support for older ones. These statistics do not directly measure the number of running installations.

Updating the repository configuration package normally applies this URL change automatically. If your network restricts outbound access, allow connections to packages.fluentd.org and fluentd.gateway.scarf.sh in addition to fluentd.cdn.cncf.io.

Download

Please visit the download page.

Follow us on X

We have been posting information about Fluentd in Japanese on @fluentd_jp. We would appreciate it if you followed the X account.