# RPC

HTTP RPC enables you to manage your Fluentd instance through HTTP endpoints. You can use this feature as a replacement of [Unix signals](/deployment/signals.md).

It is especially useful for environments where signals are not supported well e.g. Windows. This requires Fluentd to start not with `--no-supervisor` command-line option.

## Configuration

By default, HTTP RPC is not enabled. To use this feature, set the `rpc_endpoint` option:

```
<system>
  rpc_endpoint 127.0.0.1:24444
</system>
```

Now, you can manage your Fluentd instance using an HTTP client:

```
$ curl http://127.0.0.1:24444/api/plugins.flushBuffers
{"ok":true}
```

As evident from the output above, each endpoint returns a JSON object as its response.

## HTTP Endpoints

| Endpoint                                    |                                           Replacement of                                          |                           Description                           | Version |
| ------------------------------------------- | :-----------------------------------------------------------------------------------------------: | :-------------------------------------------------------------: | :-----: |
| `/api/processes.interruptWorkers`           |                         [SIGINT](/deployment/signals.md#sigint-or-sigterm)                        |                        Stops the daemon.                        |   v1.0  |
| `/api/processes.killWorkers`                |                        [SIGTERM](/deployment/signals.md#sigint-or-sigterm)                        |                        Stops the daemon.                        |   v1.0  |
| `/api/processes.zeroDowntimeRestart`        |                             [SIGUSR2](/deployment/signals.md#sigusr2)                             | Restarts Fluentd with zero-downtime. (Not supported on Windows) |  v1.18  |
| `/api/processes.flushBuffersAndKillWorkers` | [SIGUSR1](/deployment/signals.md#sigusr1) and [SIGTERM](/deployment/signals.md#sigint-or-sigterm) |               Flushes buffer and stops the daemon.              |   v1.0  |
| `/api/plugins.flushBuffers`                 |                             [SIGUSR1](/deployment/signals.md#sigusr1)                             |                  Flushes the buffered messages.                 |   v1.0  |
| `/api/config.reload`                        |                              [SIGHUP](/deployment/signals.md#sighup)                              |                      Reloads configuration.                     |   v1.0  |
| `/api/config.gracefulReload`                |                                                ---                                                |                      Reloads configuration.                     |   v1.9  |

Appendix:

* `/api/config.gracefulReload`: This is the replacement of `SIGUSR2` before v1.18. Please use `/api/processes.zeroDowntimeRestart` or `/api/config.reload` unless there is a special reason. See [SIGUSR2](/deployment/signals.md#sigusr2) for 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 an 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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