RPC

HTTP RPC enables you to manage your Fluentd instance through HTTP endpoints. You can use this feature as a replacement of Unix signals.

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	Stops the daemon.	v1.0
/api/processes.killWorkers	SIGTERM	Stops the daemon.	v1.0
/api/processes.zeroDowntimeRestart	SIGUSR2	Restarts Fluentd with zero-downtime. (Not supported on Windows)	v1.18
/api/processes.flushBuffersAndKillWorkers	SIGUSR1 and SIGTERM	Flushes buffer and stops the daemon.	v1.0
/api/plugins.flushBuffers	SIGUSR1	Flushes the buffered messages.	v1.0
/api/config.reload	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 for details.

If this article is incorrect or outdated, or omits critical information, please let us know.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.