Live system multiple overlays about dracut HOT 5 OPEN

@mid-kid How do you feel about using systemd-sysext or you prefer a solution not using systemd ?

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First time hearing of it, but it doesn't seem to be what I want. Not only because the image I'm building doesn't have systemd, but also simply because I intend to add files to /var and /etc, and both of these directories should remain writable through a tmpfs at runtime, like dracut sets them up to be.

That said, you're right in that it doesn't need to be handled in the initrd stage, I could do it in an early stage of booting after the rootfs kicks in. The thing is that I'd have to undo the dracut mounts which might break whatever dracut's doing to mount a persistent overlay.

I wonder, is anyone using the systemd-sysext program in a livecd context? I wonder what that'd look like, honestly.

from dracut.

Somewhat related, dracut can generate initramfs that prepares an overlay and copies over files from /updates - see https://github.com/dracutdevs/dracut/blob/master/modules.d/90dmsquash-live/apply-live-updates.sh .

CC @FGrose

from dracut.

Oh! That looks like a possible solution. It'd require more ram, but that's acceptable for small customizations. I'm just unable to find any documentation about it.

from dracut.

Oh! That looks like a possible solution. It'd require more ram, but that's acceptable for small customizations. I'm just unable to find any documentation about it.

There is a bit of information in the original commit message (which is over 10 years old) - f116ca1

The /updates directory needs to be in the root of the initramfs.

This can be used in combination of the idea is that some boot-loaders (e.g. grub) allows to specify more than one initramfs files - see https://www.gnu.org/software/grub/manual/grub/grub.html#index-initrd

So instead of several squashfs files, you would have several cpio files - maybe one or more with optional /updates/*

If this is working for you, than we would welcome contributions to improve the documentation (or perhaps even dracut tests) :-)

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