Creating an Ubuntu Live-CD Image

Recently I had the need to re-image some machines a few times in just a period of a week.
When re-imaging just one machine the process of installing the OS, all the updates and extra software is not that bad.
However, when that becomes a routine it can take up some time.

For most of the time I’m having to deal only with Ubuntu, so to solve that problem I installed the OS and all the updates available and also a few extra software packages that I normally use from the get go to create a baseline installation.

So whenever the need arises to re-image a machine or install a fresh copy of Ubuntu, instead of going through the same tedious process all over again, all it takes is to plug-in the pre-built disc image containing the baseline installation of the OS

The steps to create an ISO of the OS to be used as a distro or simple as a backup can be done through the software Remastersys.
In their website they have a short guide explaining the process:

The Synaptic Method:

  1. In Firefox, go to :

save file as text someplace where you can find it.

  1. In synaptic, go to Settings/Repositories; select “Authentication” tab and “Import Key File” just downloaded.

  2. Still in synaptic, go to “Other Software” tab and click “Add”, then enter the apt line and replace oneiric with either lucid, maverick, or natty to match your Ubuntu version:

    deb precise main

    or if you are using quantal

    deb quantal main

  3. Leave the repositories tab and “Reload”.

  4. Search for “remastersys” and select the packages you want to install. Edit/Apply Marked Changes.

The Manual Method

As root – issue ‘sudo su’ in the terminal window prior to the following command.

Download and apply the repository gpg key.

sudo su
wget -O – | apt-key add –

Add the following line that corresponds to your version of Ubuntu to your /etc/apt/sources.list

Remastersys Precise

deb precise main

Remastersys Quantal

deb quantal main

Now just apt-get update or reload in Synaptic to have the new Remastersys signed repository ready to use!

The main package you will need to install at the very least is “remastersys”. This is the base package with the cli version of remastersys.

If you want the official remastersys gui, install “remastersys-gui” as well which will provide you with a gui that has more features and a menu item for it.

There is also an alternate gui written in python called “remastersys-gtk” that is available.

Both will provide you with a gui that makes it much easier to use remastersys.

Link of the tutorial above
Creating custom distros with Remastersys

Creating a bootable USB drive on Mac OSX

Below are the steps needed to create a bootable USB device:

1.Download/create the ISO file you want to load in the USB

Once you have the ISO then it is time to convert to an image file:

hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso

Breaking down the command:
hdiutil description:

hdiutil uses the DiskImages framework to manipulate disk images. Common verbs include attach, detach,
verify, create, convert, compact, and burn.

The -fomat argument specifies the format of the image you want to create, by default UDZO is used.
UDZO stands for “UDIF zlib-compressed” image and UDIF is an acronym for Universal Disk Image
More info about UDIF
However, instead of UDZO we’ll use the format UDRW (UDIF read/write image)
More info on disk image formats

The argument -o defines where the image will be savedScreen Shot 2013-01-21 at 10.19.07 AM

2. Copy the image to the USB device

Before copying the image, find where the usb device is located by running:

diskutil list

diskutil description:

diskutil manipulates the structure of local disks. It provides information about, and allows the
administration of, the partitioning schemes, layouts, and formats of disks. This includes hard disks,
solid state disks, optical discs, CoreStorage volumes, and AppleRAID sets. It generally manipulates
whole volumes instead of individual files and directories.

Once you find where the device is located run:

diskutil unmountDisk /dev/diskN (N is the number of the device)

Now that the image is created and the usb device is in place it is time to copy the image to the usb:

sudo dd if=/path/to/image.img of=/dev/diskN bs=1m

The dd command will copy everything from the standard input to standard output

The if argument is to specify the input
The of the output
And the bs the block size of the data that will be copied, in this case it’s set to 1M, or 1024 bytes
Screen Shot 2013-01-21 at 11.35.02 AM

Once the dd command is finished, a popup window might show up:
Screen Shot 2013-01-21 at 11.34.51 AM

Just to make sure check if the usb was ejected:

diskutil list

Find where the device is located and if it is still there:

diskutil eject /dev/diskN

That’s all, you should have a bootable USB device by now :)

Install Ubuntu using USB drive
hdiutil man page
diskutil man page
dd man page
dd command info
Disk Images