64 lines
1.5 KiB
Markdown
64 lines
1.5 KiB
Markdown
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Undocker
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--------
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Convert a Docker image to a root file system.
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Why?
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---
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Docker images seems to be the lingua franca of distributing application
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containers. It's hell convenient. But is it the best runtime environment? Not
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for everyone.
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Undocker bridges the gap between image configurations and container runtimes:
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now you can run a Docker image with systemd-nspawn and/or lxc.
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Usage -- extract docker image
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-----------------------------
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Download `nginx` docker image from docker hub and convert it to a rootfs:
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```
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skopeo copy docker://docker.io/nginx:latest docker-archive:nginx.tar
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undocker rootfs nginx.tar - | tar -xv
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```
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Usage -- systemd-nspawn example
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-------------------------------
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```
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systemd-nspawn -D $PWD nginx -g 'daemon off;'
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```
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Usage -- lxc example
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--------------------
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Converting and creating the archive:
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```
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undocker rootfs nginx.tar - | xz -T0 > nginx.tar.xz
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undocker lxcconfig nginx.tar config
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tar -cJf meta.tar.xz config
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```
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Importing it to lxc and running it:
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```
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lxc-create -n bb -t local -- -m meta.tar.xz -f nginx.tar.xz
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lxc-start -F -n bb -s lxc.net.0.type=none
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lxc-start -F -n bb -s lxc.net.0.type=none -- /docker-entrypoint.sh nginx -g "daemon off;"
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```
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Note: automatic entrypoint does not work well with parameters with spaces; not
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sure what lxc expects here to make it work.
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Contributions
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-------------
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These are the contributions I will accept:
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- pull requests for code.
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- documentation updates.
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I am very unlikely to react to bug reports (even if they are legit) without
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accopmanying pull requests.
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