---
description: Learn how to use the Graylog Extended Format logging driver with Docker Engine
keywords: graylog, gelf, logging, driver
title: Graylog Extended Format logging driver
aliases:
- /engine/reference/logging/gelf/
- /engine/admin/logging/gelf/
- /config/containers/logging/gelf/
---
The `gelf` logging driver is a convenient format that's understood by a number of tools such as
[Graylog](https://www.graylog.org/), [Logstash](https://www.elastic.co/products/logstash), and
[Fluentd](https://www.fluentd.org). Many tools use this format.
In GELF, every log message is a dict with the following fields:
- Version
- Host (who sent the message in the first place)
- Timestamp
- Short and long version of the message
- Any custom fields you configure yourself
## Usage
To use the `gelf` 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 `gelf` and sets the `gelf-address`
option.
```json
{
"log-driver": "gelf",
"log-opts": {
"gelf-address": "udp://1.2.3.4:12201"
}
}
```
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
> `gelf-tcp-max-reconnect`) must therefore be enclosed in quotes (`"`).
You can set the logging driver for a specific container by setting the
`--log-driver` flag when using `docker container create` or `docker run`:
```console
$ docker run \
--log-driver gelf --log-opt gelf-address=udp://1.2.3.4:12201 \
alpine echo hello world
```
### GELF options
The `gelf` logging driver supports the following options:
| Option | Required | Description | Example value |
| :------------------------- | :------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------------------------------------- |
| `gelf-address` | required | The address of the GELF server. `tcp` and `udp` are the only supported URI specifier and you must specify the port. | `--log-opt gelf-address=udp://192.168.0.42:12201` |
| `gelf-compression-type` | optional | `UDP Only` The type of compression the GELF driver uses to compress each log message. Allowed values are `gzip`, `zlib` and `none`. The default is `gzip`. Note that enabled compression leads to excessive CPU usage, so it's highly recommended to set this to `none`. | `--log-opt gelf-compression-type=gzip` |
| `gelf-compression-level` | optional | `UDP Only` The level of compression when `gzip` or `zlib` is the `gelf-compression-type`. An integer in the range of `-1` to `9` (BestCompression). Default value is 1 (BestSpeed). Higher levels provide more compression at lower speed. Either `-1` or `0` disables compression. | `--log-opt gelf-compression-level=2` |
| `gelf-tcp-max-reconnect` | optional | `TCP Only` The maximum number of reconnection attempts when the connection drop. A positive integer. Default value is 3. | `--log-opt gelf-tcp-max-reconnect=3` |
| `gelf-tcp-reconnect-delay` | optional | `TCP Only` The number of seconds to wait between reconnection attempts. A positive integer. Default value is 1. | `--log-opt gelf-tcp-reconnect-delay=1` |
| `tag` | optional | A string that's appended to the `APP-NAME` in the `gelf` message. By default, Docker uses the first 12 characters of the container ID to tag log messages. Refer to the [log tag option documentation](log_tags.md) for customizing the log tag format. | `--log-opt tag=mailer` |
| `labels` | optional | Applies when starting the Docker daemon. A comma-separated list of logging-related labels this daemon accepts. Adds additional key on the `extra` fields, prefixed by an underscore (`_`). Used for advanced [log tag options](log_tags.md). | `--log-opt labels=production_status,geo` |
| `labels-regex` | optional | Similar to and compatible with `labels`. A regular expression to match logging-related labels. Used for advanced [log tag options](log_tags.md). | `--log-opt labels-regex=^(production_status\|geo)` |
| `env` | optional | Applies when starting the Docker daemon. A comma-separated list of logging-related environment variables this daemon accepts. Adds additional key on the `extra` fields, prefixed by an underscore (`_`). Used for advanced [log tag options](log_tags.md). | `--log-opt env=os,customer` |
| `env-regex` | optional | Similar to and compatible with `env`. A regular expression to match logging-related environment variables. Used for advanced [log tag options](log_tags.md). | `--log-opt env-regex=^(os\|customer)` |
> [!NOTE]
>
> The `gelf` driver doesn't support TLS for TCP connections. Messages sent to TLS-protected inputs can silently fail.
### Examples
This example configures the container to use the GELF server running at
`192.168.0.42` on port `12201`.
```console
$ docker run -dit \
--log-driver=gelf \
--log-opt gelf-address=udp://192.168.0.42:12201 \
alpine sh
```