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@@ -2,20 +2,21 @@
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:description: Organizing the Docker Root File System
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:keywords: containers, lxc, concepts, explanation, image, container
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-Layers and Union Mounts
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-=======================
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+Layers
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+======
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-In a traditional Linux boot, the kernel first mounts the root `file
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-system <filesystem>`_ as read-only, checks its integrity, and then
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-switches the whole rootfs volume to read-write mode.
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+In a traditional Linux boot, the kernel first mounts the root
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+:ref:`filesystem_def` as read-only, checks its integrity, and then
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+switches the whole rootfs volume to read-write mode.
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.. _layer_def:
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Layer
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.....
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-Docker does something similar, *except* that instead of changing the
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-file system to read-write mode, it takes advantage of a `union mount
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+When Docker mounts the rootfs, it starts read-only, as in a tradtional
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+Linux boot, but then, instead of changing the file system to
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+read-write mode, it takes advantage of a `union mount
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<http://en.wikipedia.org/wiki/Union_mount>`_ to add a read-write file
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system *over* the read-only file system. In fact there may be multiple
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read-only file systems stacked on top of each other. We think of each
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