This page describes the yaml configuration file used by Fluent Bit
One of the ways to configure Fluent Bit is using a YAML configuration file that works at a global scope.
The yaml configuration file supports the following sections:
Env
Service
Pipeline
Inputs
Filters
Outputs
The env section allows to configure variables that will be used later on this configuration file.
Example:
The service section defines global properties of the service, the keys available as of this version are described in the following table:
The following is an example of a service section:
A pipeline section will define a complete pipeline configuration, including inputs, filters and outputs subsections.
An input section defines a source (related to an input plugin). Here we will describe the base configuration for each input section. Note that each input plugin may add it own configuration keys:
The Name is mandatory and it let Fluent Bit know which input plugin should be loaded. The Tag is mandatory for all plugins except for the input forward plugin (as it provides dynamic tags).
The following is an example of an input section for the cpu plugin.
A filter section defines a filter (related to an filter plugin). Here we will describe the base configuration for each filter section. Note that each filter plugin may add it own configuration keys:
The Name is mandatory and it let Fluent Bit know which filter plugin should be loaded. The Match or Match_Regex is mandatory for all plugins. If both are specified, Match_Regex takes precedence.
The following is an example of a filter section for the grep plugin:
The outputs section specify a destination that certain records should follow after a Tag match. Currently, Fluent Bit can route up to 256 OUTPUT plugins. The configuration support the following keys:
The following is an example of an output section:
The following configuration file example demonstrates how to collect CPU metrics and flush the results every five seconds to the standard output:
| Key | Description | Default Value |
|---|---|---|
| Key | Description |
|---|---|
| Key | Description |
|---|---|
| Key | Description |
|---|---|
flush
Set the flush time in seconds.nanoseconds. The engine loop uses a Flush timeout to define when is required to flush the records ingested by input plugins through the defined output plugins.
5
grace
Set the grace time in seconds as Integer value. The engine loop uses a Grace timeout to define wait time on exit
5
daemon
Boolean value to set if Fluent Bit should run as a Daemon (background) or not. Allowed values are: yes, no, on and off. note: If you are using a Systemd based unit as the one we provide in our packages, do not turn on this option.
Off
dns.mode
Set the primary transport layer protocol used by the asynchronous DNS resolver which can be overriden 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).
log_level
Set the logging verbosity level. Allowed values are: off, error, warn, info, debug and trace. Values are accumulative, e.g: if 'debug' is set, it will include error, warning, info and debug. Note that 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.
plugins_file
Path for a plugins configuration file. A plugins configuration file allows to define paths for external plugins, for an example see here.
streams_file
Path for the Stream Processor configuration file. To learn more about Stream Processing configuration go here.
http_server
Enable built-in HTTP Server
Off
http_listen
Set listening interface for HTTP Server when it's enabled
0.0.0.0
http_port
Set TCP Port for the HTTP Server
2020
coro_stack_size
Set the coroutines stack size in bytes. The value must be greater than the page size of the running system. Don't set too small value (say 4096), or coroutine threads can overrun the stack buffer. Do not change the default value of this parameter unless you know what you are doing.
24576
scheduler.cap
Set a maximum retry time in second. The property is supported from v1.8.7.
2000
scheduler.base
Set a base of exponential backoff. The property is supported from v1.8.7.
5
Name
Name of the input plugin. Defined as subsection of the inputs section.
Tag
Tag name associated to all records coming from this plugin.
Name
Name of the filter plugin. Defined as a subsection of the filters section.
Match
A pattern to match against the tags of incoming records. It's case sensitive and support the star (*) character as a wildcard.
Match_Regex
A regular expression to match against the tags of incoming records. Use this option if you want to use the full regex syntax.
Name
Name of the output plugin. Defined as a subsection of the outputs section.
Match
A pattern to match against the tags of incoming records. It's case sensitive and support the star (*) character as a wildcard.
Match_Regex
A regular expression to match against the tags of incoming records. Use this option if you want to use the full regex syntax.
Since version 1.9, Fluent Bit supports the use of YAML for configuration.
YAML configuration is tech preview so not recommended for production.