Notes of a Programmer: Creating Small Footprint Linux Virtual Machine

Although it may be easier to download a Linux virtual appliance, it can be fun to create linux virtual machines yourself. In particular, we may be interested in creating small footprint Linux virtual machines -- it would be easy to put it on a USB drive or let other people to download it. This post documents the process that I use to create Ubuntu 14.04 (Trusty) Linux virtual machines and reduce the image size of the virtual machines. The key idea is (1) to remove non-essential packages as much as possible; (2) to increase the compression of virtual machine images by zeroing virtual disks; and (3) to compact and compress the virtual machine image.

Download 32-bit Ubuntu 14.04 (Trusty) ISO file and install it as a guest operating system under VMware Player or VirtualBox.
To make copy & paste instructions easier, install VMware Tools.

Install Linux headers and the build essential packages

sudo apt-get install linux-headers-generic build-essential

Then install VMware Tools
Restart the virtual machine.

By default, Ubuntu 14.04 runs the Ubuntu Unity desktop environment. It prevents us from entering the VMware Unity mode. I now get rid of the Ubuntu Unity desktop environment. I learned the command from this post.


sudo apt-get purge \
     unity unity-common unity-services \
     unity-lens-\* unity-scope-\* unity-webapps-\* \
     gnome-control-center-unity \
     hud libunity-core-6\* libunity-misc4 \
     libunity-webapps\* appmenu-gtk \
     appmenu-gtk3 appmenu-qt\* overlay-scrollbar\* \
     activity-log-manager-control-center \
     firefox-globalmenu thunderbird-globalmenu \
     libufe-xidgetter0 xul-ext-unity \
     xul-ext-webaccounts webaccounts-extension-common \
     xul-ext-websites-integration \
     gnome-control-center gnome-session

Then, install GNOME 3.


sudo apt-get install gnome-session-fallback

Now, remove the default games.


sudo apt-get game\* purge ace-of-penguins gnome-mahjongg gnome-mines \
             berusky biniax2 gnurobbo groundhog gtkballs hitori \
             four-in-a-row gnect gbrainy gnome-sudoku chess\* \
             nibbles\* solitaire\* iagno\* klotski\* tetravex\* \
             drascula gtkboard oneisenough openyahtzee ri-li \
             scribble swell-foop quadrapassel\* lightsoff \
             five-or-more gnome-robots gtali

Remove a few network applications.


sudo apt-get purge webbrowser-app thunderbird\*

Remove Libre Office. This can save a few hundred megabytes.
```
sudo apt-get purge libreoffice\*
```
Now get rid of the "Ubuntu Software Center".
```
sudo apt-get purge software-center\*
```
The /var/cache directory can easily have a few hundred megabytes data. We can trim it down.
```
sudo apt-get clean
```
Do an automove,
```
sudo apt-get autoremove
```
Now remove GNOME and Ubuntu documentation.
```
  sudo apt-get purge yelp\*
  
```
Now, you can install whatever important software you want to include in the virtual machine, e.g., I am installing Octave,
```
sudo apt-get install octave
```
We would probably want to compress the virtual machine image before we pass it to someone. We need to replace every byte of free space on the disk by 0's.
```
dd if=/dev/zero of=zerofile; \
   sleep 5; sync; \
   sleep 5; sync; \
   sleep 5; sync; \
   rm -f zerofile;
```
I am using VMware Player. Using it, I do a "defragment" and then "compact" the virtual disk. The guest system must be off before you can do it. Of course, you can do the same using VirtualBox.
Finally, I compress the folder of the virtual machine. The zip archieve file is about 1 GB.

In addition, you may save a few megabytes, by removing all log and temporary files. The tool bleachbit can help. Before you zero the hard disk, install and run the tool.


sudo apt-get install bleachbit; sudo bleachbit

Notes of a Programmer

Thursday, September 18, 2014

Creating Small Footprint Linux Virtual Machine

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