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From Iso To Vagrant Box

This is my recipe on how to automatically create an up-to-date Ubuntu Vagrant box file from an iso.

You need the following ingredients:

I use the minimal ISO because the regular ISO does not always contains the latest package versions, so you’ll not end up having to update your system just right after you install it. This is because the mini ISO installs the latest packages right of the internet; it is also much smaller than the regular ISO.

Packer is used to install Ubuntu into a Vagrant box file. Packer uses a template file to describe that process. The template uses a preseed file to drive the Debian installer (aka d-i) to automatically install Ubuntu in a VirtualBox Virtual Machine, which will be later exported into a Vagrant box file.

Vagrant is used to automatically create and setup (or provision) a development environment inside a Virtual Machine. Vagrant uses a Vagrantfile script to describe that process.

VirtualBox is used to actually run the Virtual Machine.

You can find the sources at rgl/ubuntu-vagrant, but read along to known more details.

The following sections assume that you already have Packer, Vagrant and VirtualBox installed and available on your PATH.

Packer Template

Create the template:

  "variables": {
    "disk_size": 8192
  "builders": [
      "name": "amd64-virtualbox",
      "type": "virtualbox-iso",
      "guest_os_type": "Ubuntu_64",
      "guest_additions_mode": "attach",
      "headless": false,
      "http_directory": ".",
      "vboxmanage": [
        ["modifyvm", "{{.Name}}", "--memory", "2048"],
        ["modifyvm", "{{.Name}}", "--cpus", "2"],
        ["modifyvm", "{{.Name}}", "--vram", "32"]
      "disk_size": "{{user `disk_size`}}",
      "hard_drive_interface": "sata",
      "iso_url": "",
      "iso_checksum": "4f783f3917ed4c663c9a983f4ee046fc",
      "iso_checksum_type": "md5",
      "ssh_username": "vagrant",
      "ssh_password": "vagrant",
      "ssh_wait_timeout": "60m",
      "boot_wait": "5s",
      "boot_command": [
        "/linux initrd=/initrd.gz",
        " nofb",
        " fb=false",
        " auto=true",
        " url=http://{{.HTTPIP}}:{{.HTTPPort}}/preseed.txt",
        " hostname=vagrant",
        " DEBCONF_DEBUG=5",
        " --",
        " nofb",
      "shutdown_command": "echo vagrant | sudo -S poweroff"

  "provisioners": [
      "type": "shell",
      "execute_command": "echo vagrant | sudo -S bash {{.Path}}",
      "scripts": [""]

  "post-processors": [
      "type": "vagrant",
      "output": "ubuntu-14.10-{{.BuildName}}.box"


  • To known the available boot options open the boot/grub/grub.cfg file inside the mini.iso file.

  • While d-i is installing Ubuntu you can press alt+f2 to open a shell and inspect the environment. e.g. cat /proc/cmdline ; env ; ls -l /target

  • You can also press alt+f4 to see what is going on (its a console running tail -f /var/log/syslog). Press alt+f1 to return to the d-i.

  • The DEBCONF_DEBUG=5 was added into the kernel command line to aid us in debugging the preseed installation. At install time, when d-i asks a question, look at the last debconf variable that is mentioned on syslog (press alt+f4), its probably the one you need to set to answer the question.

  • At a console, to change the keyboard map, type e.g. loadkeys pt.

  • You only have the Nano text editor on the install console. To search text inside it press ctrl+w. To repeat the search press alt+w. To search backwards press alt+b.


Create the preseed:

# save the log for debugging purposes.
d-i preseed/late_command string cp /var/log/syslog /target/home/vagrant/preseed.log

d-i debian-installer/locale string en_US.UTF-8
d-i localechooser/supported-locales multiselect en_US.UTF-8, pt_PT.UTF-8

d-i keyboard-configuration/layoutcode string pt
d-i console-setup/ask_detect boolean false

d-i mirror/country string manual
d-i mirror/http/hostname string
d-i mirror/http/directory string /ubuntu
d-i mirror/http/proxy string

d-i clock-setup/utc boolean true
d-i time/zone string Europe/Lisbon

d-i partman-auto/method string regular
d-i partman-auto/choose_recipe select atomic
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

d-i grub-installer/only_debian boolean true
d-i finish-install/reboot_in_progress note

d-i passwd/user-fullname string vagrant
d-i passwd/username string vagrant
d-i passwd/user-password password vagrant
d-i passwd/user-password-again password vagrant
d-i user-setup/allow-password-weak boolean true
d-i user-setup/encrypt-home boolean false

tasksel tasksel/first multiselect
d-i pkgsel/include string openssh-server
d-i pkgsel/upgrade select full-upgrade
d-i pkgsel/update-policy select none


  • Also see the example preseed at the Ubuntu Installation Guide.

  • A preseed/late_command was added to aid in debugging the preseed; it creates a preseed.log file with what happened at preseed.

  • keyboard-configuration/layoutcode accepts similar values as loadkeys(1), e.g. us, pt, etc.

  • time/zone accepts a filename relative to the /usr/share/zoneinfo/ directory.

  • tasksel/first is a comma separated list, .e.g. ubuntu-server, xubuntu-desktop.

  • You can later add support for other locales. e.g. I like to use ConEmu and it does not support UTF-8 at all, so I do:

sudo sh -c 'echo en_US.ISO-8859-15 ISO-8859-15 >> /var/lib/locales/supported.d/local'
sudo sudo dpkg-reconfigure locales
export LANG=en_US.ISO-8859-15 LANGUAGE=en_US
#sudo sh -c "echo 'LANG=$LANG' > /etc/default/locale" # optional. maybe just do this on your .bashrc

Provisioning script

Create the provisioning script:

# abort this script when a command fails or a unset variable is used.
set -eu
# echo all the executed commands.
set -x

# let our user use root permissions without sudo asking for a password (because
# d-i adds us into the sudo group, but we must be on the admin group instead).
# alternatively: echo 'vagrant ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/vagrant
groupadd -r admin
usermod -a -G admin vagrant
gpasswd -d vagrant sudo
sed -i -e 's,%admin ALL=(ALL) ALL,%admin ALL=(ALL) NOPASSWD:ALL,g' /etc/sudoers

# installing the vagrant public key.
# NB vagrant will replace it on the first run.
install -d -m 700 /home/vagrant/.ssh
pushd /home/vagrant/.ssh
wget --no-check-certificate -O authorized_keys
chmod 600 ~/.ssh/authorized_keys
chown -R vagrant:vagrant .

# install the VirtualBox Guest Additions.
# this will be installed at /opt/VBoxGuestAdditions-VERSION.
# REMOVE_INSTALLATION_DIR=0 is to fix a bug in
# See
apt-get -y -q install gcc dkms
mkdir -p /mnt
mount /dev/sr1 /mnt
while [ ! -f /mnt/ ]; do sleep 1; done
REMOVE_INSTALLATION_DIR=0 /mnt/ --target /tmp/VBoxGuestAdditions
rm -rf /tmp/VBoxGuestAdditions
umount /mnt

# disable the DNS reverse lookup on the SSH server. this stops it from
# trying to resolve the client IP address into a DNS domain name, which
# is kinda slow and does not normally work when running inside VB.
echo UseDNS no >> /etc/ssh/sshd_config

# disable the graphical terminal. its kinda slow and useless on a VM.
sed -i -E 's,#(GRUB_TERMINAL\s*=).*,\1console,g' /etc/default/grub

# use the up/down arrows to navigate the bash history.
# NB to get these codes, press ctrl+v then the key combination you want.
"\e[A": history-search-backward
"\e[B": history-search-forward
set show-all-if-ambiguous on
set completion-ignore-case on

# clean packages.
apt-get -y autoremove
apt-get -y clean

# zero the free disk space -- for better compression of the box file.
#dd if=/dev/zero of=/EMPTY bs=1M ; rm -f /EMPTY


Build it:

packer validate ubuntu-14.10.json
packer inspect ubuntu-14.10.json
#time packer build -var disk_size=81920 ubuntu-14.10.json
time packer build ubuntu-14.10.json

NB you can also modify the disk size with the disk_size user variable. e.g. for 80GB, build with: packer build -var disk_size=81920 ubuntu-14.10.json.

NB the box will compress to about 720MB (with 1.2G of used space).

NB in my machine, the build took about 15 minutes to create the final box file.

Add the box to vagrant:

vagrant box add ubuntu-14.10-amd64


Create a test VM based on our created box:

mkdir -p test && cd test
vagrant init ubuntu-14.10-amd64
time vagrant up

NB in my machine, this takes about 45 seconds to boot.

Connect to the console, and kick the tires:

vagrant ssh
uname -a
df -h
less preseed.log
cat /proc/cmdline

Poweroff the VM, and destroy it:

vagrant halt
vagrant destroy
cd ..
rm -rf test

When you no longer need the box in vagrant, you can also remove it with:

vagrant box remove ubuntu-14.10-amd64

And that’s it!

You could now proceed on how to bootstrap a GitHub Pages blog inside a Xubuntu desktop.