.iso File

Info: You must have a working GRUB installation already, if not checkout the Preparations for Boot .

Why would you need this? When you don't have a KVM or just don't want to use ILO, iDRAC, iPMI or other management tools to mount an ISO.

This snippet is from a try to install Fedora CoreOS from an ISO file named install.io from the /boot partition.

Example grub.cfg contents (coreos.inst.install_dev=sda would use the sda device for installation in case of *CoreOS):

set default=0
set timeout=5
# Fedora Kickstart Install
 menuentry "Fedora Kickstart Install" {
    search --no-floppy --fs-uuid __BOOT_PART_UUID__ --set root
    # Booting an ISO
    loopback loop /install.iso
    linux (loop)/images/vmlinuz coreos.inst=yes coreos.inst.install_dev=sda coreos.inst.ignition_url=http://example.com/example.ign
    initrd (loop)/images/initramfs.img
}

It worked fine though the original case was to load the Ignition file from the boot disk which didn't work, a Webserver/ Matchbox server was required to load the Ignition file from.

.img File

Preparations for 'Booting XYZ FIle'