The following packages will be required in order to use cloud images as virtual machines :

The Ubuntu Cloud Image can be downloaded from the Internet by various means. This example shows how to easily download the 12.04 Precise image using wget :

wget -O my_new_vm.img.dist http://cloud-images.ubuntu.com/server/releases\
/12.04/release/ubuntu-12.04-server-cloudimg-amd64-disk1.img

The user-data file contains configuration elements that will be provided to the cloud image and applied at the first boot of the virtual machine using cloud-init. The first three elements, password, chpasswd and ssh_pwauth are mandatory. You should add an ssh key that you have created beforehand using ssh-keygen otherwise you will not be able to connect remotely to your virtual machine.

Use the following command to create the my-user-data file that will contain your user specific data :

$ cat > my-user-data <<EOF
#cloud-config
password: passw0rd
chpasswd: { expire: False }
ssh_pwauth: True
ssh_authorized_keys:
 - ssh-rsa {insert your own ssh public key here}
EOF

The two qemu-img command is not strictly necessary :

Use the following command to prepare your file to be used as a virtual machine disk:

$ qemu-img convert -O qcow2 my_new_vm.img.dist my_new_vm.img

This action will create a second disk image that will be provided to the virtual machine as a second disk. The cloud-init initialization process will fetch this data and configure the virtual machine appropriately

$ cloud-localds my-seed.img my-user-data

You will need to tailor the following XML domain definition file to your need in order to create the libvirt domain. If the files that you have generated are in /home/ubuntu, the template can be used as is.

Use the following command to create the template file :

$ cat > my_new_vm.xml <<EOF
<domain type='kvm'>
  <name>my_new_vm</name>
  <memory unit='MiB'>1024</memory>
  <currentMemory unit='MiB'>1024</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
    <type arch='x86_64' machine='pc-1.2'>hvm</type>
    <boot dev='hd'/>
    <bootmenu enable='no'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/home/ubuntu/my_new_vm.img'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/home/ubuntu/my-seed.img'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <interface type='network'>
      <source network='default'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <graphics type='vnc' port='-1' autoport='yes'/>
  </devices>
</domain>
EOF

The last few commands remaining are standard libvirt commands used to define and start your virtual machine :

$ virsh define my_new_vm.xml
$ virsh start my_new_vm
$ virsh console my_new_vm

If everything goes as planned, you should see the boot sequence appear in your console session. After the normal boot sequence you will see something similar to the following :

cloud-init start-local running: Wed, 10 Apr 2013 12:30:25 +0000. up 1.67 seconds
no instance data found in start-local
ci-info: lo    : 1 127.0.0.1       255.0.0.0       .
ci-info: eth0  : 1 192.168.122.113 255.255.255.0   52:54:00:c2:fd:e1
ci-info: route-0: 0.0.0.0         192.168.122.1   0.0.0.0         eth0   UG
ci-info: route-1: 192.168.122.0   0.0.0.0         255.255.255.0   eth0   U
cloud-init start running: Wed, 10 Apr 2013 12:30:30 +0000. up 6.30 seconds
found data source: DataSourceNoCloud [seed=/dev/sda]

This section can be particularly useful to identify the IP address of the virtual machine that you have just started. The cloud-init sequence will continue, creating the SSH information. It should indicates proper completion by the following line :

cloud-init boot finished at Wed, 10 Apr 2013 12:30:35 +0000. Up 10.93 seconds

Your new virtual machine is now available. You can exit out of the virsh console command using <Ctrl>]

You can now connect to your virtual machine using the ssh key that you have created previously :

$ ssh -i $HOME/.ssh/id_rsa [email protected]

. Vmbuilder will fetch the various package and build a virtual machine tailored for your needs in about a minute. vmbuilder is a script that automates the process of creating a ready to use Linux based VM. The currently supported hypervisors are KVM and Xen.

You can pass command line options to add extra packages, remove packages, choose which version of Ubuntu, which mirror etc. On recent hardware with plenty of RAM, tmpdir in /dev/shm or using a tmpfs, and a local mirror, you can bootstrap a VM in less than a minute.

First introduced as a shell script in Ubuntu 8.04 LTS, ubuntu-vm-builder started with little emphasis as a hack to help developers test their new code in a virtual machine without having to restart from scratch each time. As a few Ubuntu administrators started to notice this script, a few of them went on improving it and adapting it for so many use case that Soren Hansen (the author of the script and Ubuntu virtualization specialist, not the golf player) decided to rewrite it from scratch for Intrepid as a python script with a few new design goals:

But the general principles and commands remain the same.

It is assumed that you have installed and configured libvirt and KVM locally on the machine you are using. For details on how to perform this, please refer to:

We also assume that you know how to use a text based text editor such as nano or vi. If you have not used any of them before, you can get an overview of the various text editors available by reading the PowerUsersTextEditors page. This tutorial has been done on KVM, but the general principle should remain on other virtualization technologies.

The name of the package that we need to install is python-vm-builder. In a terminal prompt enter:

sudo apt-get install python-vm-builder

Defining a virtual machine with Ubuntu's vmbuilder is quite simple, but here are a few thing to consider:

The vmbuilder command has 2 main parameters: the virtualization technology (hypervisor) and the targeted distribution. Optional parameters are quite numerous and can be found using the following command:

vmbuilder kvm ubuntu --help

As this example is based on KVM and Ubuntu 13.04 (Raring Ringtail), and we are likely to rebuild the same virtual machine multiple time, we'll invoke vmbuilder with the following first parameters:

sudo vmbuilder kvm ubuntu --suite raring --flavour virtual --arch i386  \
-o --libvirt qemu:///system

The --suite defines the Ubuntu release, the --flavour specifies that we want to use the virtual kernel (that's the one used to build a JeOS image), the --arch tells that we want to use a 32 bit machine, the -o tells vmbuilder to overwrite the previous version of the VM and the --libvirt tells to inform the local virtualization environment to add the resulting VM to the list of available machines.

Notes:

In this example we will be installing a package (Limesurvey) that accesses a MySQL database and has a web interface. We will therefore require our OS to provide us with:

This is done using vmbuilder by specifying the --addpkg option multiple times:

--addpkg PKG
  Install PKG into the guest (can be specfied multiple times)

However, due to the way vmbuilder operates, packages that have to ask questions to the user during the post install phase are not supported and should instead be installed while interactivity can occur. This is the case of Limesurvey, which we will have to install later, once the user logs in.

Other packages that ask simple debconf question, such as mysql-server asking to set a password, the package can be installed immediately, but we will have to reconfigure it the first time the user logs in.

If some packages that we need to install are not in main, we need to enable the additional repositories using --comp and --ppa:

--components COMP1,COMP2,...,COMPN
           A comma separated list of distro components to include (e.g. main,universe).
           This defaults to "main"
--ppa=PPA  Add ppa belonging to PPA to the vm's sources.list.

Limesurvey not being part of the archive at the moment, we'll specify it's PPA (personal package archive) address so that it is added to the VM /etc/apt/source.list, so we add the following options to the command line:

--addpkg apache2 --addpkg apache2-mpm-prefork --addpkg apache2-utils \
         --addpkg apache2.2-common --addpkg dbconfig-common --addpkg libapache2-mod-php5 \
         --addpkg mysql-client --addpkg php5-cli --addpkg php5-gd --addpkg php5-ldap \
         --addpkg php5-mysql --addpkg wwwconfig-common --addpkg mysql-server --ppa nijaba

Two option are available to us:

In our case we'll use Limesurvey as example web application for which we wish to provide a virtual appliance. As noted before, we've made a version of the package available in a PPA (Personal Package Archive).

Here is the command with all the options discussed above:

sudo vmbuilder kvm ubuntu --suite raring --flavour virtual --arch i386 -o \ 
         --libvirt qemu:///system --ip 192.168.0.100 --hostname myvm \
         --part vmbuilder.partition --user user --name user --pass default \
         --addpkg apache2 --addpkg apache2-mpm-prefork --addpkg apache2-utils \
         --addpkg apache2.2-common --addpkg dbconfig-common \ 
         --addpkg libapache2-mod-php5 --addpkg mysql-client --addpkg php5-cli \ 
         --addpkg php5-gd --addpkg php5-ldap --addpkg php5-mysql \
         --addpkg wwwconfig-common --addpkg mysql-server \
         --addpkg unattended-upgrades --addpkg acpid --ppa nijaba \
         --mirror http://mirroraddress:9999/ubuntu