NAS setup: USB, dropbear, LUKS, RAID-5, chroot...

[syntern]

I'd like to create a setup where the boot is from a read-only USB drive.
It should boot into a minimal environment that has a dropbear SSH server, it gets its init command / encryption password through SSH, and with that it stops. (Maybe it also starts a nebula node).
The init command will decrypt disks (using LUKS), setup the raid-5 over them, and then mount the volume.
It should then chroot into a directory on that volume, starting local services (cron, docker, ...).

Has anybody a similar setup?

[zen_desu]

I do something similar, but i enter keys over serial/ipmi. This is generally more compatible and helps keep your initramfs relatively simple.

If you're using mdraid and assemble the raid device, then put LUKS on that, you only need one key. If you do something like btrfs raid, you probably want a unique key per device. I prefer that method, even though it adds a bit of complexity to the initramfs process.
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