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Hi, |
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my knowledge of booting from an initramfs is limited right now, so keep |
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that in mind. However, I will attempt to answer some of your questions. |
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On Fri, Aug 05, 2011 at 10:06:48PM +0200, Sven Vermeulen wrote: |
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> I'm all in favor of documenting what an initramfs does (or at least what it |
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> is supposed to do), how it works, how to create one, how to debug issues |
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> while booting with one, etc. |
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> |
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> That said, I'm a bit hesitant to describing that we "recommend" it |
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> regardless of the situation. What is wrong with describing when? At least |
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> inform our users that the udev rules have evolved to more than just "detect |
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> and mknod" scripts and that they are now relying on files and binaries |
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> available in other locations, like /usr and /var. |
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It looks like the situation where we will have to have one is if /usr |
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and /var are not on the same file system as /, because of how udev has |
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evolved. |
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> How does the tool that creates an initramfs know which files to copy from |
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> /usr and /var anyhow? |
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My understanding is that nothing gets copied from /usr and /var, and it |
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doesn't have to. |
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Here is my basic understanding of how the boot sequence works: |
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1) rootfs is mounted on /. Rootfs contains the contents of the |
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initramfs. |
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2) the init program inside the initramfs is run. |
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3) This init program will mount the real /usr and /var. |
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4) This init program will then mount the real root on top of rootfs. |
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(there is a call that does this, but I'll need to look that up again). I |
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vaguely remember reading that you don't mount the real root on /newroot |
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then pivet_root as mentioned earlier in this thread; I think that is |
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part of the old initrd method. |
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5) This init program will now run /sbin/init or which ever init program |
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the user wants to run. |
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> Also, how well does this play with all our profiles (so not only the popular |
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> architectures)? What about SELinux and/or grSecurity's RBAC model? Are these |
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> supported throughout the initramfs? |
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This one I can't answer. |
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Regards, |
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|
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William |
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