Fluentd
Search…
Command Line Option
This article describes the command-line tools and its options in fluentd project.

fluentd

Following are the fluentd command-line options (fluentd -h):
1
Usage: fluentd [options]
2
-s, --setup [DIR=/etc/fluent] install sample configuration file to the directory
3
-c, --config PATH config file path (default: /etc/fluent/fluent.conf)
4
--dry-run Check fluentd setup is correct or not
5
--show-plugin-config=PLUGIN [DEPRECATED] Show PLUGIN configuration and exit(ex: input:dummy)
6
-p, --plugin DIR add plugin directory
7
-I PATH add library path
8
-r NAME load library
9
-d, --daemon PIDFILE daemonize fluent process
10
--under-supervisor run fluent worker under supervisor (this option is NOT for users)
11
--no-supervisor run fluent worker without supervisor
12
--workers NUM specify the number of workers under supervisor
13
--user USER change user
14
--group GROUP change group
15
-o, --log PATH log file path
16
--log-rotate-age AGE generations to keep rotated log files
17
--log-rotate-size BYTES sets the byte size to rotate log files
18
--log-event-verbose enable log events during process startup/shutdown
19
-i CONFIG_STRING, inline config which is appended to the config file on-the-fly
20
--inline-config
21
--emit-error-log-interval SECONDS
22
suppress interval seconds of emit error logs
23
--suppress-repeated-stacktrace [VALUE]
24
suppress repeated stacktrace
25
--without-source invoke a fluentd without input plugins
26
--use-v1-config Use v1 configuration format (default)
27
--use-v0-config Use v0 configuration format
28
--strict-config-value Parse config values strictly
29
--enable-input-metrics Enable input plugin metrics on fluentd
30
--enable-size-metrics Enable plugin record size metrics on fluentd
31
-v, --verbose increase verbose level (-v: debug, -vv: trace)
32
-q, --quiet decrease verbose level (-q: warn, -qq: error)
33
--suppress-config-dump suppress config dumping when fluentd starts
34
-g, --gemfile GEMFILE Gemfile path
35
-G, --gem-path GEM_INSTALL_PATH Gemfile install path (default: $(dirname $gemfile)/vendor/bundle)
36
--conf-encoding ENCODING specify configuration file encoding
37
--disable-shared-socket Don't open shared socket for multiple workers
Copied!

Important Options

    -g, --gemfile: Fluentd starts with bundler-managed dependent plugins.
    --suppress-config-dump: Fluentd starts without configuration dump. If you do not want to show the configuration in fluentd logs, e.g. it contains private keys, then this option is useful.
    --suppress-repeated-stacktrace: If true, suppresses the stacktrace in fluentd logs. Since v0.12, this option is true by default.
    --without-source: Fluentd starts without input plugins. This option is useful for flushing buffers with no new incoming events.
    -i, --inline-config: If fluentd is used on XaaS which does not support persistent disks, this option is useful.
    --no-supervisor: If you want to use your supervisor tools, this option avoids double supervisor.

Set via Configuration File

Some options can be set via <system> directive via configuration file. See configuration file article for more on <system> directive.

fluent-cat

The fluent-cat command sends an event to fluentd in_forward/in_unix plugin. This is particularly useful for testing.
Here is its usage (fluent-cat --help):
1
Usage: fluent-cat [options] <tag>
2
-p, --port PORT fluent tcp port (default: 24224)
3
-h, --host HOST fluent host (default: 127.0.0.1)
4
-u, --unix use unix socket instead of tcp
5
-s, --socket PATH unix socket path (default: /var/run/fluent/fluent.sock)
6
-f, --format FORMAT input format (default: json)
7
--json same as: -f json
8
--msgpack same as: -f msgpack
9
--none same as: -f none
10
--message-key KEY key field for none format (default: message)
Copied!

Example

Send JSON message with debug.log tag to the local fluentd instance:
1
echo '{"message":"hello"}' | fluent-cat debug.log
Copied!
Send JSON message to an instance of fluentd on another machine on the network:
1
echo '{"message":"hello"}' | fluent-cat debug.log --host testserver --port 24225
Copied!

fluent-plugin-config-format

It generates the formatted configuration document with the specified format for a plugin.
Here is its usage (fluent-plugin-config-format -h):
1
Usage: fluent-plugin-config-format [options] <type> <name>
2
3
Output plugin config definitions
4
5
Arguments:
6
type: input,output,filter,buffer,parser,formatter,storage,service_discovery
7
name: registered plugin name
8
9
Options:
10
--verbose Be verbose
11
-c, --compact Compact output
12
-f, --format=FORMAT Specify format. (markdown,txt,json)
13
-I PATH Add PATH to $LOAD_PATH
14
-r NAME Load library
15
-p, --plugin=DIR Add plugin directory
16
-t, --table Use table syntax to dump parameters
Copied!

Example

Generate a README style document from the plugin's config parameters:
1
fluent-plugin-config-format output null
Copied!
Generate an old-style output from the plugin's config parameters:
1
fluent-plugin-config-format -f txt output null
Copied!
Generate a markdown table style output from the plugin's config parameters:
1
fluent-plugin-config-format -f markdown --table output null
Copied!

fluent-plugin-generate

It generates the Fluentd plugin project template. It is good for starting to Fluentd plugin development for using the new API plugin. For more details, refer to the Generating plugin project skeleton section.
Here is its usage (fluent-plugin-generate -h);
1
Usage: fluent-plugin-generate [options] <type> <name>
2
3
Generate a project skeleton for creating a Fluentd plugin
4
5
Arguments:
6
type: input,output,filter,parser,formatter,storage
7
name: Your plugin name (fluent-plugin- prefix will be added to <name>)
8
9
Options:
10
--[no-]license=NAME Specify license name (default: Apache-2.0)
Copied!

fluent-ctl

Control fluentd process using Signals or Windows Event.
1
Usage: fluent-ctl COMMAND PID
2
3
Commands:
4
shutdown
5
restart
6
flush
7
reload
Copied!

Example

1
fluent-ctl shutdown 11111
Copied!

fluent-cap-ctl

Control Linux Capability for Fluentd. See Linux Capability article.
If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.
Last modified 1mo ago