fluent-bit -> *.yaml | Change extension for generated config

[linuxmail]

Hello,

we need to switch from NXlog to fluent-bit. Fluent-bit supports old-style .conf (ini format) and the newer YAML *.yaml. We want to use fluent-bit with YAML config and this requires an extension *.yaml. I did not found any option to create with graylog-sidecar a *.yaml, instead of *.conf.

time="2025-09-18T15:46:17+02:00" level=info msg="Adding process runner for: fluent-bit-container-687f88d6bfac767af91e5793"
time="2025-09-18T15:46:17+02:00" level=info msg="[fluent-bit-container-687f88d6bfac767af91e5793] Configuration change detected, rewriting configuration file."
time="2025-09-18T15:46:17+02:00" level=info msg="Trying to create directory for: /var/lib/graylog-sidecar/generated/687f88d6bfac767af91e5793/fluent-bit-container.conf"
time="2025-09-18T15:46:17+02:00" level=error msg="[fluent-bit-container-687f88d6bfac767af91e5793] Collector configuration file is not valid, waiting for the next update."
time="2025-09-18T15:46:17+02:00" level=error msg="[fluent-bit-container-687f88d6bfac767af91e5793] Validation command output: Fluent Bit v4.0.4\n* Copyright (C) 2015-2025 The Fluent Bit Authors\n* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd\n* https://fluentbit.io\n\n______ _                  _    ______ _ _             ___  _____ \n|  ___| |                | |   | ___ (_) |           /   ||  _  |\n| |_  | |_   _  ___ _ __ | |_  | |_/ /_| |_  __   __/ /| || |/' |\n|  _| | | | | |/ _ \\ '_ \\| __| | ___ \\ | __| \\ \\ / / /_| ||  /| |\n| |   | | |_| |  __/ | | | |_  | |_/ / | |_   \\ V /\\___  |\\ |_/ /\n\\_|   |_|\\__,_|\\___|_| |_|\\__| \\____/|_|\\__|   \\_/     |_(_)___/ \n\n\n[2025/09/18 15:46:17] [error] [config] error in /var/lib/graylog-sidecar/generated/687f88d6bfac767af91e5793/fluent-bit-container.conf:1: undefined value - check config is in valid classic format\n[2025/09/18 15:46:17] [error] configuration file contains errors, aborting.\n"

Is there any workaround?

cu denny

[bernd]

@linuxmail Unfortunately, fluent-bit decides the config format based on the config file extension. Sidecar always generates config files with a .conf extension, regardless of the format.

We would need to make the file name format configurable for collectors in the Sidecar UI.

There doesn't seem to be a workaround in fluent-bit to force the YAML format.