# 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`): ``` Usage: fluentd [options] -s, --setup [DIR=/etc/fluent] install sample configuration file to the directory -c, --config PATH config file path (default: /etc/fluent/fluent.conf) --dry-run Check fluentd setup is correct or not --show-plugin-config=PLUGIN [DEPRECATED] Show PLUGIN configuration and exit(ex: input:dummy) -p, --plugin DIR add plugin directory -I PATH add library path -r NAME load library -d, --daemon PIDFILE daemonize fluent process --under-supervisor run fluent worker under supervisor (this option is NOT for users) --no-supervisor run fluent worker without supervisor --workers NUM specify the number of workers under supervisor --user USER change user --group GROUP change group --umask UMASK change umask -o, --log PATH log file path --log-rotate-age AGE generations to keep rotated log files --log-rotate-size BYTES sets the byte size to rotate log files --log-event-verbose enable log events during process startup/shutdown -i CONFIG_STRING, inline config which is appended to the config file on-the-fly --inline-config --emit-error-log-interval SECONDS suppress interval seconds of emit error logs --suppress-repeated-stacktrace [VALUE] suppress repeated stacktrace --without-source invoke a fluentd without input plugins --with-source-only Invoke a fluentd only with input plugins. The data is stored in a temporary buffer. Send SIGWINCH to cancel this mode and process the data (Not supported on Windows). --use-v1-config Use v1 configuration format (default) --use-v0-config Use v0 configuration format --strict-config-value Parse config values strictly --enable-input-metrics [DEPRECATED] Enable input plugin metrics on fluentd --disable-input-metrics Disable input plugin metrics on fluentd --enable-size-metrics Enable plugin record size metrics on fluentd -v, --verbose increase verbose level (-v: debug, -vv: trace) -q, --quiet decrease verbose level (-q: warn, -qq: error) --suppress-config-dump suppress config dumping when fluentd starts -g, --gemfile GEMFILE Gemfile path -G, --gem-path GEM_INSTALL_PATH Gemfile install path (default: $(dirname $gemfile)/vendor/bundle) --conf-encoding ENCODING specify configuration file encoding --disable-shared-socket Don't open shared socket for multiple workers ``` ### 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. * `--with-source-only` (Not supported on Windows): See [Source Only Mode](https://docs.fluentd.org/deployment/source-only-mode) for details. * `-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 `` directive via configuration file. See [configuration file](https://docs.fluentd.org/configuration/config-file) article for more on `` 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`): ``` Usage: fluent-cat [options] -p, --port PORT fluent tcp port (default: 24224) -h, --host HOST fluent host (default: 127.0.0.1) -u, --unix use unix socket instead of tcp -s, --socket PATH unix socket path (default: /var/run/fluent/fluent.sock) -f, --format FORMAT input format (default: json) --json same as: -f json --msgpack same as: -f msgpack --none same as: -f none --message-key KEY key field for none format (default: message) --time-as-integer Send time as integer for v0.12 or earlier --retry-limit N Specify the number of retry limit (default: 5) --event-time TIME_STRING Specify the time expression string (default: nil) ``` ### Example Send JSON message with `debug.log` tag to the local fluentd instance: ``` echo '{"message":"hello"}' | fluent-cat debug.log ``` Send JSON message to an instance of fluentd on another machine on the network: ``` echo '{"message":"hello"}' | fluent-cat debug.log --host testserver --port 24225 ``` ## `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`): ``` Usage: fluent-plugin-config-format [options] Output plugin config definitions Arguments: type: input,output,filter,buffer,parser,formatter,storage,service_discovery name: registered plugin name Options: --verbose Be verbose -c, --compact Compact output -f, --format=FORMAT Specify format. (markdown,txt,json) -I PATH Add PATH to $LOAD_PATH -r NAME Load library -p, --plugin=DIR Add plugin directory -t, --table Use table syntax to dump parameters ``` ### Example Generate a README style document from the plugin's config parameters: ``` fluent-plugin-config-format output null ``` Generate an old-style output from the plugin's config parameters: ``` fluent-plugin-config-format -f txt output null ``` Generate a markdown table style output from the plugin's config parameters: ``` fluent-plugin-config-format -f markdown --table output null ``` ## `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](https://docs.fluentd.org/plugin-development#generating-plugin-project-skeleton). Here is its usage (`fluent-plugin-generate -h`); ``` Usage: fluent-plugin-generate [options] Generate a project skeleton for creating a Fluentd plugin Arguments: type: input,output,filter,parser,formatter,storage name: Your plugin name (fluent-plugin- prefix will be added to ) Options: --[no-]license=NAME Specify license name (default: Apache-2.0) ``` ## `fluent-ctl` Control `fluentd` process using [Signals](https://docs.fluentd.org/deployment/signals) or Windows Event. ``` Usage: fluent-ctl COMMAND [PID_OR_SVCNAME] Commands: shutdown restart flush reload dump ``` ### Example You can specify the process id of the supervisor process. ``` fluent-ctl shutdown 11111 ``` If you run Fluentd as a Windows service, then you can omit `PID_OR_SVCNAME` when the service name is the default value `fluentdwinsvc`. ``` fluent-ctl dump ``` ### About `dump` This function is mainly for Windows. On Windows, this makes all Fluentd processes (including all worker processes) dump their internal status to the system temp directory (`C:\\Windows\\Temp`). This is the same behavior as sending SIGCONT to all processes on non-Windows. Since this uses [SIGDUMP](https://github.com/frsyuki/sigdump), you can change the output path by specifying `SIGDUMP_PATH` environment variable. Note that the path has to be a file path. ```powershell $ $env:SIGDUMP_PATH="/sigdump/sigdump.log" # The directory `sigdump` has to exist. $ fluentd -c ... $ fluent-ctl dump # At another shell. ``` Then Fluentd dumps files as following. Each process id is automatically added to the path. ``` ... [info]: fluent/log.rb:330:info: dump to /sigdump/sigdump-41544.log. ... [info]: #0 fluent/log.rb:330:info: dump to /sigdump/sigdump-21152.log. ... [info]: #1 fluent/log.rb:330:info: dump to /sigdump/sigdump-15656.log. ... ``` As for non-Windows, you don't have to use this function because you can manually send SIGCONT to each process. Although you can use this function on non-Windows, this just sends SIGCONT to the supervisor process, so you can get only the status of the supervisor process. ## `fluent-cap-ctl` Control Linux Capability for Fluentd. See [Linux Capability](https://docs.fluentd.org/deployment/linux-capability) article. If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is an open-source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). 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