Drop schedule announcement about EOL of Fluent Package (fluent-package) 5

Hi users and developers!

As already planned before, we announce the dropping schedule for Fluent Package 5 (LTS) development.

About Fluent Package v5

Since fluent-package 5.0.0 was released in 2023, fluent-package 5 has been maintained for a long time.

As new major version of fluent-package 6 was released in August 2025, we decided to stop maintaining fluent-package 5 in Dec 31, 2025.

LTS version of fluent-package v6 will be planned support until Dec, 2027. It will meet for your enterprise services.

Scheduled end of life - Dec 2025

As you know, already stepping down maintenance activity, new minor update for fluent-package 5 will not be shipped anymore. fluent-package v5.0.9 should be the last release of this series, it was shipped in Dec 19, 2025.

Thus, we recommend using fluent-package v6 for new deployment :)

How to migrate to Fluent Package v6

There is a good article to do it.

Follow the above instructions.

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fluent-package v5.0.9 has been released

Hi users!

We have released fluent-package v5.0.9 on December 19, 2025. Fluent Package is a stable distribution package of Fluentd. (successor of td-agent v4)

This is a maintenance release of v5.0.x LTS series.

Fluent Package v5.0.9

This article explains the changes in Fluent Package v5.0.9.

Changes

Updated bundled Fluentd from v1.16.10 to v1.16.11

Fluentd v1.16.11 includes the following fixes:

  • out_forward: fix issue where could cause output to stop when using <security> and TLS setting together under unstable network environments
    • In an unstable network environment, if communication is lost during the forward plugin's connection process after TLS is established, the out_forward connection process could fall into an infinite loop, causing log output to stop.
    • We applied the existing hard_timeout parameter setting to this connection process to enable interruption and recovery via timeout.

Download

Please see the download page.

Announcement

The final release of v5 LTS series

This release (v5.0.9) is planned to be the final version of the v5 LTS series. We strongly recommend upgrading to Fluent Package v6 LTS series for next long term support.

Please refer to Scheduled support lifecycle announcement about Fluent Package v6.

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Fluentd v1.16.11 has been released

Hi users!

We have released v1.16.11 on 2025-12-09. ChangeLog is here.

This release is expected to be the final release of v1.16 series.

This release will be bundled for upcoming fluent-package LTS version v5.0.9!

Bug Fixes

out_forward: fix issue where could cause output to stop when using <security> and TLS setting together under unstable network environments

This issue occurs when using out_forward with TLS enabled in unstable network environments.

If the communication is lost during the connection process immediately after TLS is established, the out_forward connection process could fall into an infinite loop. As a result, the log output stops completely.

To address this, we have updated the plugin to apply the existing hard_timeout parameter to this connection phase. This introduces a mechanism to interrupt the stuck process via timeout and allow it to recover.

Enjoy logging!

Announcement

The final release of v1.16 series

This release (v1.16.11) is planned to be the final version of the v1.16 series. We strongly recommend upgrading to Fluentd v1.19 series for next long term support.

Please refer to Scheduled support lifecycle announcement about Fluent Package v6.

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fluent-package v6.0.1 has been released

Hi users!

We have released fluent-package v6.0.1 on 2025-11-11. Fluent Package is a stable distribution package of Fluentd. (successor of td-agent v4)

This is a maintenance release of v6.0.x LTS series.

Fluent Package v6.0.1

Fluent Package v6.0.1 includes the following improvements:

  • Updated bundled Ruby to 3.4.7
  • Updated bundled Fluentd from v1.19.0 to v1.19.1
  • Fixed an issue where Fluentd’s temporary directory could be deleted by tmpfiles.d
  • Fixed Windows installer error for custom install path containing spaces

This article explains the changes in Fluent Package v6.0.1.

Changes

Updated bundled Ruby to 3.4.7

Ruby 3.4.7 includes multiple bug and security fixes. For details, please see the Ruby 3.4.7 release notes.

Updated bundled Fluentd from v1.19.0 to v1.19.1

Fluentd v1.19.1 includes the following fixes:

  • YAML configuration: Added Support for Array Notation

Previously, when specifying multiple values, you had to use a comma-separated list such as: retryable_response_codes: 503, 504.

With this update, you can now use more YAML-style array notations:

retryable_response_codes: [503, 504]

or

retryable_response_codes:
  - 503
  - 504

Note: The special element $arg has supported array notation from earlier versions.

Note: There is still a known YAML syntax issue where specifying a single int value for an Array option causes a config error. For details, please refer to #5149.

Fixed an issue where Fluentd’s temporary directory could be deleted by tmpfiles.d

This issue, which was previously fixed in Fluent Package v5.0.8, has now been included in Fluent Package v6.0.1.

On some Linux distributions, tmpfiles.d is configured as follows, and files or directories in /tmp that remain unused for more than 10 days are deleted:

q /tmp 1777 root root 10d

When using the out_file or out_secondary_file plugins, Fluentd uses temporary directory like /tmp/fluentd-lock-{...}/, depending on the config. If there is no output with out_file or out_secondary_file for an extended period, the temporary directory could be deleted by tmpfiles.d.

If the temporary directory is deleted while Fluentd is running, the following error occurs continuously in out_file and out_secondary_file output:

2025-09-11 14:33:29 +0900 [warn]: #2 failed to flush the buffer. retry_times=0 next_retry_time=2025-09-11 14:33:30 +0900 chunk="63e7fdca888e679a6fcdefb0c120bf58" error_class=Errno::ENOENT error="No such file or directory @ rb_sysopen - /tmp/fluentd-lock-20250911-1545462-74fvkh/fluentd-foo.lock"

Normally, some output is written periodically, so this issue is rare. If it occurs, you can restore normal operation by restarting Fluentd before reaching the retry limit.

In this release, we added a rule to /usr/lib/tmpfiles.d/fluentd.conf to exclude /tmp/fluentd-lock-{...}/ from automatic deletion.

Fixed Windows installer error for custom install path containing spaces

This fixes an issue in the Windows installer of Fluent Package v6.0.0.

When installing Fluent Package to a path containing spaces (e.g., C:\Program Files\fluentd), an error could occur during installation. This issue has been fixed in v6.0.1.

Download

Please visit the download page.

Announcement

About next LTS schedule

We plan to release the next LTS version of fluent-package v6.0.2 at February 2026. The content of updates are still TBD.

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Fluentd v1.19.1 has been released

Hi users!

We have released v1.19.1 on 2025-11-06. ChangeLog is here.

This release is a maintenance release of v1.19 series.

This release will be bundled for upcoming fluent-package LTS version v6.0.1!

Bug Fixes

YAML configuration: Added Support for Array Notation

Previously, when specifying multiple values, you had to use a comma-separated list such as: retryable_response_codes: 503, 504.

With this update, you can now use more YAML-style array notations:

retryable_response_codes: [503, 504]

or

retryable_response_codes:
  - 503
  - 504

Note: The special element $arg has supported array notation from earlier versions.

Note: There is still a known YAML syntax issue where specifying a single int value for an Array option causes a config error. For details, please refer to #5149.

Enjoy logging!

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