= rescue-boot

This project holds scripts that prepares a "rescue" boot image file
with a Devuan ceres minbase filesystem.

* +./minbase-strap.sh+ prepares boot-ceres-$ARCH.img

  - +./minbase-strap-bios.sh+ include fragment preparing bios boot equipment

  - +./minbase-strap-uefi.sh+ include fragment preparing uefi boot equipment

  - +./minbase-strap-mkimg.sh+ include fragment packaging into disk file

* +./run.sh boot-ceres-$ARCH.img+ boots it up in a virtual machine.

== About the boot image preparation

The rescue boot image is a full disk image with two partitions. The
first is a FAT partition that contains a linux kernel and initrd for
the kernel and boot equipments using syslinux for both legacy bios and
UEFI bios boot.

The initrd.gz file is quite large makign the partition somewhat larger
than 100M and this makes it less ameniable as boot image for a hybrid
ISO (which has a 32M limit).

The preparation populates a root filesystem in the FS directory by
using debootstrap followed by certain "Captain's Picks" to include
partcular choice software.

The scripting asks firstly for a kernel choice and then an init script
choice to optionally replace the "standard" initrd init script with
some rescue variant.

== About the virtual machine setup

The run.sh script starts a QEMU system emulator for the boot image
given on the command line. E.g.,

    $ ./run.sh boot-ceres-amd64.img

With environment setting EFI=yes, the emulation uses UEFI boot. E.g.

    $ EFI=yes ./run.sh boot-ceres-amd64.img

The script assumes the host has a "vde2" setup with a "vde-switch"
using control directory "/run/vde.ctl". Any alternatie network setup
needs script hands-on to change the "NET=.." variable.