Luks | inetshell

A LUKS server that hangs and never comes back: watchdog, SSH unlock with dropbear, and netconsole

Three pieces so a hang costs a minute instead of hours: the watchdog reboots, dropbear in the initramfs lets you type the LUKS passphrase over SSH, and netconsole keeps the kernel’s last messages on another box.

LUKS: back up and restore the header, and add, change or remove keys

No header, no data, passphrase or not: back it up off the disk and back it up again after every key change, because the old backup keeps the old keys.