---
description: Learn how to use the fluentd logging driver
keywords: Fluentd, docker, logging, driver
title: Fluentd logging driver
aliases:
  - /engine/reference/logging/fluentd/
  - /reference/logging/fluentd/
  - /engine/admin/logging/fluentd/
  - /config/containers/logging/fluentd/
---

The `fluentd` logging driver sends container logs to the
[Fluentd](https://www.fluentd.org) collector as structured log data. Then, users
can use any of the [various output plugins of
Fluentd](https://www.fluentd.org/plugins) to write these logs to various
destinations.

In addition to the log message itself, the `fluentd` log
driver sends the following metadata in the structured log message:

| Field            | Description                                                                                                                                           |
| :--------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------- |
| `container_id`   | The full 64-character container ID.                                                                                                                   |
| `container_name` | The container name at the time it was started. If you use `docker rename` to rename a container, the new name isn't reflected in the journal entries. |
| `source`         | `stdout` or `stderr`                                                                                                                                  |
| `log`            | The container log                                                                                                                                     |

## Usage

Some options are supported by specifying `--log-opt` as many times as needed:

- `fluentd-address`: specify a socket address to connect to the Fluentd daemon, ex `fluentdhost:24224` or `unix:///path/to/fluentd.sock`.
- `tag`: specify a tag for Fluentd messages. Supports some Go template markup, ex `{{.ID}}`, `{{.FullID}}` or `{{.Name}}` `docker.{{.ID}}`.

To use the `fluentd` driver as the default logging driver, set the `log-driver`
and `log-opt` keys to appropriate values in the `daemon.json` file, which is
located in `/etc/docker/` on Linux hosts or
`C:\ProgramData\docker\config\daemon.json` on Windows Server. For more about
configuring Docker using `daemon.json`, see [daemon.json](/reference/cli/dockerd.md#daemon-configuration-file).

The following example sets the log driver to `fluentd` and sets the
`fluentd-address` option.

```json
{
  "log-driver": "fluentd",
  "log-opts": {
    "fluentd-address": "fluentdhost:24224"
  }
}
```

Restart Docker for the changes to take effect.

> [!NOTE]
>
> `log-opts` configuration options in the `daemon.json` configuration file must
> be provided as strings. Boolean and numeric values (such as the value for
> `fluentd-async` or `fluentd-max-retries`) must therefore be enclosed
> in quotes (`"`).

To set the logging driver for a specific container, pass the
`--log-driver` option to `docker run`:

```console
$ docker run --log-driver=fluentd ...
```

Before using this logging driver, launch a Fluentd daemon. The logging driver
connects to this daemon through `localhost:24224` by default. Use the
`fluentd-address` option to connect to a different address.

```console
$ docker run --log-driver=fluentd --log-opt fluentd-address=fluentdhost:24224
```

If container cannot connect to the Fluentd daemon, the container stops
immediately unless the `fluentd-async` option is used.