75 lines
3.2 KiB
Markdown
75 lines
3.2 KiB
Markdown
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---
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description: Describes how to use the local logging driver.
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keywords: local, docker, logging, driver
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redirect_from:
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- /engine/reference/logging/local/
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- /engine/admin/logging/local/
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title: Local File logging driver
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---
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The `local` logging driver captures output from container's stdout/stderr and
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writes them to an internal storage that is optimized for performance and disk
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use.
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By default, the `local` driver preserves 100MB of log messages per container and
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uses automatic compression to reduce the size on disk. The 100MB default value is based on a 20M default size
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for each file and a default count of 5 for the number of such files (to account for log rotation).
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> *Note*
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>
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> The `local` logging driver uses file-based storage. The file-format and
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> storage mechanism are designed to be exclusively accessed by the Docker
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> daemon, and should not be used by external tools as the implementation may
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> change in future releases.
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## Usage
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To use the `local` driver as the default logging driver, set the `log-driver`
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and `log-opt` keys to appropriate values in the `daemon.json` file, which is
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located in `/etc/docker/` on Linux hosts or
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`C:\ProgramData\docker\config\daemon.json` on Windows Server. For more about
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configuring Docker using `daemon.json`, see
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[daemon.json](../../../engine/reference/commandline/dockerd.md#daemon-configuration-file).
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The following example sets the log driver to `local` and sets the `max-size`
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option.
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```json
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{
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"log-driver": "local",
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"log-opts": {
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"max-size": "10m"
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}
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}
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```
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Restart Docker for the changes to take effect for newly created containers. Existing containers do not use the new logging configuration.
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You can set the logging driver for a specific container by using the
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`--log-driver` flag to `docker container create` or `docker run`:
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```bash
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$ docker run \
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--log-driver local --log-opt max-size=10m \
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alpine echo hello world
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```
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### Options
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The `local` logging driver supports the following logging options:
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| Option | Description | Example value |
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|:------------|:--------------------------------------------------------------------------------------------------------------------------------------------------------------|:---------------------------|
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| `max-size` | The maximum size of the log before it is rolled. A positive integer plus a modifier representing the unit of measure (`k`, `m`, or `g`). Defaults to 20m. | `--log-opt max-size=10m` |
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| `max-file` | The maximum number of log files that can be present. If rolling the logs creates excess files, the oldest file is removed. A positive integer. Defaults to 5. | `--log-opt max-file=3` |
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| `compress` | Toggle compression of rotated log files. Enabled by default. | `--log-opt compress=false` |
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### Examples
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This example starts an `alpine` container which can have a maximum of 3 log
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files no larger than 10 megabytes each.
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```bash
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$ docker run -it --log-driver local --log-opt max-size=10m --log-opt max-file=3 alpine ash
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```
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