boot issues after converting running linux to vm manually

Question

I did a file copy of a running debian8 installation to a image. Following is the proceedure.

1. create a vdisk image - raw / vdi.
2. mount it locally.
3. do a file wise copy of a running linux distro:

   rsync -aAXv --delete --exclude={"/dev/","/proc/","/sys/","/tmp/","/run/","/mnt/","/media/","/lost+found","/home/"} /* "$TMPDIR"

4. install extlinux bootloader and related /boot/extlinux.conf, update /etc/fstab, umount and boot.

I am able to boot using qemu. Able to login to console mode.

ISSUES:

1. It fails at trying to mount swap partitions, but no reference is provided in /etc/fstab.
2. It fails to load kernel modules.
3. I see message starting lightdm, but next VT is displayed to login.
4. I haven't recreated initram-fs for target, could this cause the problem?

Please help.

-- regards, JB

Answer 1

Have been able to resolve some of the issues, resulting in making a bootable vm image from a running system.

Issue:

1. No effect.
2. No effect.
3. This is actually 1-issue and 1-mistake, I had a custom xorg.conf with a specific driver, removing the xorg.conf makes booting qemu into graphical mode. The other is due to plain slowness of qemu, you just need to wait for a long time for lightdm to startup.
4. No effect.

I've summarized the entire process in a script for convinience:

#!/bin/bash
# create bootable image from running linux distro

IMG_format="raw"
IMG_name="debian8"
IMG_size="13G"

LNX_image="vmlinuz-4.4.3"
LNX_initrd="initrd.img-4.4.3"
LNX_rootdev="/dev/sda"

TMPDIR="/mnt/vmd/"
WRKDIR="/media/domnic/tmp1"

create_img(){
  IMG="$WRKDIR/$IMG_name.$IMG_format"
  echo "image => $IMG"

  if [ -a "$IMG"]; then
    echo "vm [$IMG] already exists... skipped!"
  else
    if [ "vdi" == "$IMG_format" ]; then
      #- create .vdi
      VBoxManage createhd --filename $IMG --size $(( IMG_size * 1024 ))
    else
      #- or create image on .raw disk
      fallocate -l $IMG_size $IMG
      mkfs.ext4 -F $IMG
    fi
  fi
}

mount_img(){
  echo "mount => $TMPDIR"
  IMG="$WRKDIR/$IMG_name.$IMG_format"
  if [ ! -d "$TMPDIR" ]; then
    mkdir -p $TMPDIR
  fi

  if [ "vdi" == "$IMG_format" ]; then
    #- mount .vdi
    vdfuse -a -f $IMG /mnt/vdi
    mount -o loop /mnt/vdi/1 $TMPDIR
  else
    #- mount image to tmpdir
    mount $IMG $TMPDIR
  fi
}

clone_img(){
  echo "clone => $TMPDIR"
  #- copy files
  rsync -aAX --delete --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found","/home/*"} /* "$TMPDIR"

  #- install bootloader
  extlinux --install $TMPDIR/boot

  #- update bootloader
  #-- qemu default: root=/dev/sda
  cat > $TMPDIR/boot/syslinux/extlinux.conf <<- EOM
DEFAULT $IMG_name_$LNX_image
LABEL   $IMG_name_$LNX_image
SAY     Booting $IMG_name - $LNX_image
LINUX   /boot/$LNX_image
INITRD  /boot/$LNX_initrd
APPEND  root=$LNX_rootdev rw
EOM

  #-- remove invalid entries from $TMPDIR/etc/fstab
  echo "/dev/sda   /   ext4   defaults   0   1" > $TMPDIR/etc/fstab

  #- unmount image and boot
  umount $TMPDIR
  if [ "vdi" == "$IMG_format" ]; then
    umount /mnt/vdi  
  fi
}

start_vm(){
  IMG="$WRKDIR/$IMG_name.$IMG_format"
  echo "vm => $IMG"

  qemu-system-i386 \
    -display sdl \
    -soundhw ac97 \
    -vga cirrus \
    $IMG
}

case $1 in
  create_img)
    create_img
    ;;
  mount_img)
    mount_img
    ;;
  clone_img)
    clone_img
    ;;
  start_vm)
    start_vm
    ;;
esac