[Libguestfs] Extlinux with guestfish

[Richard W.M. Jones]

On Tue, Oct 20, 2015 at 04:40:09PM +0100, slim tabka wrote:
> Hi everyone,
> 
> I'm working with libguestfs 1.30.3 on Centos 7 host.
> I encountered a problem when I wanted to install extlinux with guestfish as
> a bootloader for my guests and I always get this error:
> 
> SYSLINUX 4.05 EDD 0x54f93f16 Copyright (C) 1994-2010 H. Peter Anvin et al
> ERROR: No configuration file found
> No default or UI configuration directive found!
> boot: _
> 
> 
> 
> *This is how I create the virtual machines:*
> 
> lvcreate -n vm_name  -L 9G vm_volumes
> 
> parted /dev/vm_volumes/vm_name mklabel msdos
> parted -a optimal /dev/vm_volumes/vm_name  mkpart primary ext4 0% 100%
> parted /dev/vm_volumes/vm_name  set 1 boot on
> 
> kpartx -av /dev/vm_volumes/vm_name
> 
> mkfs.ext4 /dev/mapper/loop0p1
> 
> mount /dev/mapper/loop0p1 /mnt/clone
> 
> tar -zxf /root/centos7_template.tar.gz -C /mnt/clone/
> 
> umount /mnt/clone
> kpartx -dv /dev/vm_volumes/vm_name

Strange way to do this, as libguestfs can do all this.

> /root/libguestfs-1.30.3/run guestfish -i -a /dev/vm_volumes/{vm_name}
> << _EOF_ \n\
> 
> #####mbr.bin and syslinux already existant in centos7_template.tar.gz####
> copy-file-to-device /boot/mbr.bin /dev/sda size:440 \n\
> extlinux /boot \n\
> part-set-bootable /dev/sda 1 true \n\
> _EOF_
> 
> *And this is the syslinux.cfg file:*
> 
> DEFAULT linux
>         LABEL linux
>           SAY Booting the kernel
>           KERNEL /boot/vmlinuz-3.10.0-229.el7.x86_64
>           INITRD /boot/initramfs-3.10.0-229.el7.x86_64.img
>           APPEND ro root=UUID={{ UUID }}

Did you copy the syslinux.cfg file into the guest?  The error message
you reported sounds like extlinux is installed but cannot read its
config file.

Anyway, here's how I used these APIs:

  https://rwmj.wordpress.com/2013/04/04/new-in-libguestfs-use-syslinux-or-extlinux-to-make-bootable-guests/#content

It's in Perl, but the same commands will work fine in guestfish.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html