fstab rootfs / switch_root

[pwFoo]

Hi @troglobit,

I've done some first steps to build my own running linux system based on finit and busybox / alpine. Looks really great and works fine so far.
Great job with finit 👍

Now I thinking about rootfs and found an example to mount "/" from /etc/fstab. Is it something like switch_root or just mount a partition to "/"?

My idea was to mount squashfs and a overlayfs to / or squashfs with some persistent additional / mounts.

Is there an example with fstab rootfs mount / switch_root or squashfs / overlayfs?

Many thanks!

[troglobit]

Thanks, that's very kind of you :)

About 10-15 years ago there was a pivot root implementation in Finit. Since then nobody's use that. What works, and is in use today, is a basic mount -a which uses /etc/fstab by default. We recently added an option to use a different fstab from the finit command line (kernel command line with the -- separator from the boot loader).

I have setups with Alpine, Debian working with Finit, there use the native ext2 partitions. However, for embedded systems I employ Buildroot and there's an example of using a squashfs root in https://github.com/troglobit/myLinux -- specifically, see https://github.com/troglobit/myLinux/blob/main/board/common/rootfs/etc/fstab.ro which is used for make run when an amd64 build is started in Qemu. Another (very similar) example is https://github.com/westermo/netbox/blob/master/board/common/rootfs/etc/fstab which is always used. Both use a BusyBox mount helper to actually mount the things, but I think you'll get the gist of it from the fstab file.