From the Canyon Edge -- :-Dustin

Friday, July 2, 2010

Creating Ubuntu Server Disk Images using live-helper

I recently showed you how to create Ubuntu Server images using vmbuilder, but promised to also show how to use live-helper. Without further ado...

Start by installing live-helper.

sudo apt-get install live-helper

If you want a splash image for the boot loader, grab one. Here's an example


Next, we use lh_config with a lengthy set of options, to build:
  • disable apt recommends (keep the image small)
  • build 64 bit (for large memory instances)
  • enable main and universe
  • build a usb disk style image
  • append a few kernel options (like "toram" and "noprompt")
  • use the syslinux bootloader
  • build from ubuntu lucid
  • use the linux-image-server kernel
  • add a few packages (like "byobu" and "vim")
  • add your boot splash image
  • set the boot timeout to 2 seconds
  • use aufs
  • set the root disk size to 2GB

/usr/share/live-helper/helpers/lh_config \
--apt-recommends false \
--architecture amd64 \
--archive-areas "main universe" \
--binary-image usb-hdd \
--bootappend-live "toram persistent noprompt" \
--bootloader syslinux \
--distribution lucid \
--exposed-root true \
--initramfs casper \
--linux-flavours server \
--linux-packages linux-image \
--mode ubuntu \
--packages "byobu vim" \
--syslinux-timeout 2 \
--syslinux-splash ./byobu_192.png \
--union-filesystem aufs \
--virtual-root-size 2000

Configure any "local hooks". These are scripts of your design that can modify your image inside of the chroot.

cat >config/chroot_local-hooks/ <<EOF
ln -sf /usr/bin/byobu-launch /etc/profile.d/
chmod +x config/chroot_local-hooks/

Now, you can perform the build. This takes about 8 minutes for me on my laptop, with an SSD and local mirror.

sudo /usr/share/live-helper/helpers/lh_build
Finally, test your image. You can run it in KVM.

kvm -m 512 -hda binary.img
Alternatively, you could write this directly to a hard drive, as an install. Note that this will overwrite ALL data on that drive. Use with great care!!!

dd if=binary.img of=/dev/sda



  1. Incredibly useful! Thanks, Dustin.

  2. Hi Dustin,

    Apologies in advanced for posting this question here. You can definitely delete it after a few days have passed by.
    I have decided to contact you because you seem to be a guru of Ubuntu, and -having read a previous post of you on the matter- I figured you could probably provide me with sensible answers.
    Im not totally sure what happened last night on my Lucid, but somehow my gnome-power-manager broke-down, which meant I couldn't access the X-server.
    I read a few pages of documentation through my Windows partition, but unfortunately nothing that was being said there solved my problem.
    After a few hours of fiddling-around, I decided to reinstall an image, under a different username, with the idea to later copy the contents of home to my new home (as I dont want to have to re-do the whole look of the gnome environment).
    But to my surprise (I didnt know this was happening until now), I realised that ubuntu has encrypted my content automatically, so that when I logged in under my new username I cannot access my previous home folder.
    I read a bit about it and it says its been done through ecrypts, so I got in the process of manually mounting it to /home/myprevioususername/Private but it doesnt let me do it. Heres why:
    if I use ecryptfs-add-passphrase --fnek and then
    sudo ecryptfs-mount-private /home/myprevioususername/.Private /home/myprevioususername/Private

    I enter the login passphrase (when I first installed Lucid I remember getting a demand for a passphrase -I thought it was supposed to be the same as the login password so I duplicated it) and then it says
    "insterted auto tok with sig [digits&letters] into the user session keyring", and then
    "fopen: no such file or directory"


    I also tried the option
    sudo mount -t ecryptfs /home/previoususername/.Private /home/prev.../Private
    I go through the options and then it says
    "error mounting eCryptfs: [-2] No such file or directory"
    same error?

    Am I doing somethign wrong? Can I recover the data from my old username home folder?

    Thanks a mil!

  3. Oh, I just read your notice on Launchpad. Will move my enquiry there.


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