Service

The service section defines global properties of the service. The available configuration keys are:

Key	Description	Default Value
flush	Sets the flush time in seconds.nanoseconds. The engine loop uses a flush timeout to define when to flush the records ingested by input plugins through the defined output plugins.	1
grace	Sets the grace time in seconds as an integer value. The engine loop uses a grace timeout to define the wait time on exit.	5
daemon	Specifies whether Fluent Bit should run as a daemon (background process). Possible values: yes, no, on, and off. Don't enable when using a Systemd-based unit, such as the one provided in Fluent Bit packages.	off
dns.mode	Sets the primary transport layer protocol used by the asynchronous DNS resolver. Can be overridden on a per-plugin basis.	UDP
log_file	Absolute path for an optional log file. By default, all logs are redirected to the standard error interface (stderr).	none
log_level	Sets the logging verbosity level. Possible values: off, error, warn, info, debug, and trace. Values are cumulative. For example, if debug is set, it will include error, warning, info, and debug. The trace mode is only available if Fluent Bit was built with the WITH_TRACE option enabled.	info
parsers_file	Path for a parsers configuration file. Multiple parsers_file entries can be defined within the section. Parsers can be declared directly in the parsers section of YAML configuration files.	none
plugins_file	Path for a plugins configuration file. This file specifies the paths to custom plugins (.so files) that Fluent Bit can load at runtime. Plugins can be declared directly in the plugins section of YAML configuration files.	none
streams_file	Path for the stream processor configuration file. This file defines the rules and operations for stream processing in Fluent Bit. Stream processor configurations can also be defined directly in the streams section of YAML configuration files.	none
http_server	Enables the built-in HTTP server.	off
http_listen	Sets the listening interface for the HTTP Server when it's enabled.	0.0.0.0
http_port	Sets the TCP port for the HTTP server.	2020
hot_reload	Enables hot reloading of configuration with SIGHUP.	on
coro_stack_size	Sets the coroutines stack size in bytes. The value must be greater than the page size of the running system. Setting the value too small (for example, 4096) can cause coroutine threads to overrun the stack buffer. For best results, don't change this parameter from its default value.	24576
scheduler.cap	Sets a maximum retry time in seconds.	2000
scheduler.base	Sets the base of exponential backoff.	5
json.convert_nan_to_null	If enabled, NaN is converted to null when Fluent Bit converts msgpack to JSON.	false
json.escape_unicode	Controls how Fluent Bit serializes non‑ASCII / multi‑byte Unicode characters in JSON strings. When enabled, Unicode characters are escaped as \uXXXX sequences (characters outside BMP become surrogate pairs). When disabled, Fluent Bit emits raw UTF‑8 bytes.	true
sp.convert_from_str_to_num	If enabled, the stream processor converts strings that represent numbers to a numeric type.	true
windows.maxstdio	If specified, adjusts the limit of stdio. Only provided for Windows. Values from 512 to 2048 are allowed.	512

For scheduler and retry details, see scheduling and retries.

Configuration example

The following configuration example that defines a service section with hot reloading enabled and a pipeline with a random input and stdout output:

service:
  flush: 1
  log_level: info
  http_server: true
  http_listen: 0.0.0.0
  http_port: 2020
  hot_reload: on

pipeline:
  inputs:
    - name: random

  outputs:
    - name: stdout
      match: '*'