# multiprocess

By default, Fluentd only uses a single CPU core on the system. The `in_multiprocess` Input plugin enables Fluentd to use multiple CPU cores by spawning multiple child processes. One Fluentd user is using this plugin to handle 10+ billion records / day.

## Install

`in_multiprocess` is NOT included in td-agent by default. td-agent users must install fluent-plugin-multiprocess manually.

* Fluentd: `fluent-gem install fluent-plugin-multiprocess`
* td-agent v2:

  `/usr/sbin/td-agent-gem install fluent-plugin-multiprocess`
* td-agent v1:

  `/usr/lib/fluent/ruby/bin/fluent-gem install fluent-plugin-multiprocess`

## Example Configuration

```
<source>
  @type multiprocess

  <process>
    cmdline -c /etc/fluent/fluentd_child1.conf --log /var/log/fluent/fluentd_child1.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
  <process>
    cmdline -c /etc/fluent/fluentd_child2.conf --log /var/log/fluent/fluentd_child2.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
  <process>
    cmdline -c /etc/fluent/fluentd_child3.conf --log /var/log/fluent/fluentd_child3.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
</source>
```

Please see the [Config File](https://docs.fluentd.org/0.12/configuration/config-file) article for the basic structure and syntax of the configuration file.

Especially for daemonized fluentd (ex: td-agent), \`--log\` option MUST be specified to put logs of child processes.

## Parameters

### type (required)

The value must be `multiprocess`.

### graceful\_kill\_interval

The interval to send the signal to gracefully shut down the process (default: 2sec).

### graceful\_kill\_interval\_increment

The increment time, when graceful shutdown fails (default: 3sec).

### graceful\_kill\_timeout

The timeout, to identify the failure of graceful shutdown (default: 60sec).

### process (required)

The `process` section sets the command line arguments of a child process. This plugin creates one child process for each section.

### cmdline (required)

The `cmdline` option is required in a section

### sleep\_before\_start

This parameter sets the wait time before starting the process (default: 0sec).

### sleep\_before\_shutdown

This parameter sets the wait time before shutting down the process (default: 0sec).

#### log\_level option

The `log_level` option allows the user to set different levels of logging for each plugin. The supported log levels are: `fatal`, `error`, `warn`, `info`, `debug`, and `trace`.

Please see the [logging article](https://docs.fluentd.org/0.12/deployment/logging) for further details.

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 a open source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). All components are available under the Apache 2 License.


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