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28 lines
1.5 KiB
Markdown
28 lines
1.5 KiB
Markdown
# LinuxKit losetup
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Image to setup a loop device backed by a regular file in a [linuxkit](https://github.com/linuxkit/linuxkit)-generated image. The typical use case is to have a portable storage location which can be used to persist settings or other files. Can be combined with the `linuxkit/dm-crypt` package for protection.
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## Usage
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The setup is a one time step during boot:
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```yaml
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onboot:
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- name: losetup
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image: linuxkit/losetup:<hash>
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command: ["/usr/bin/loopy", "-c", "/var/test.img"]
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```
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The above will associate the file `/var/test.img` with `/dev/loop0` and will also create it if it's not present.
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The container by default bind-mounts `/var:/var` and `/dev:/dev`. Usually the loop-file will reside on external storage which should be typically mounted under `/var` hence the choice of the defaults. If the loop-file is located somewhere else and you need a different bind-mount for it then do not forget to explicitly bind-mount `/dev:/dev` as well or else `losetup` will fail.
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### Options
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|Option|Default|Required|Notes|
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|`-c` or `--create`||No|Creates the file if not present. If `--create` is not specified and the file is missing then the loop setup will obviously fail.|
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|`-s` or `--size`|10|No|If `--create` was specified and the file is not present then this sets the size in MiB of the created file. The file will be filled from `/dev/zero`.|
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|`-d` or `--dev`|`/dev/loop0`|No|Loop device which should be associated with the file.|
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|`<file>`||**Yes**|The file to use as backing storage.|
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