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The problem: you cannot boot a paravirtualised machine from a CD-ROM for the purposes of installing a virtual machine. You may also be on a wireless link set up by NetworkManager and WLAN0 isn’t a bridged interface.

Here’s the solution:

  1. Download the ISO of your favourite distro and burn to DVD, then mount on your machine (this will probably happen just by inserting the disc on your drive).  If a window opens in your desktop, highlight the path in the address bar and copy it to the system clipboard (CTRL-C).
  2. Install Apache and start the apache/httpd service
  3. In /var/www/html (/var/www on debian, I believe) simply create a symbolic link to the directory where the DVD is mounted.  In this example, I am using CentOS:
     #  ln -s /media/CentOS_5.4_Final/ centos
  4. Now create the virtual machine, by starting up virt-manager, ensuring that it can connect to Dom0 and select New…
  5. In the Installation Source section of the virtual machine creation dialog,  specify the following parameter: Installation media URL: http://localhost/centos (the path to the installer repository)
  6. In the “type of network” selection, select Virtual Interface.
  7. Click through the rest of the set up – but BEFORE YOU COMPLETE IT, GET READY TO PAUSE THE VM. The virtual machine will start up automatically when you finish the set-up steps.
  8. As soon as you start the VM, the initial bootstrapping files should load and the distribution’s kernel should start up.   Only when the console window opens should you pause it!
  9. If you are using CentOS, you now need to modify the configuration file that’s been created, following these steps:
  1. Download the Xen kernel and initial ramdisk from here: http://mirror.centos.org/centos/5/os/x86_64/images/xen/ (change the path if you’re using an i386 host)
  2. Save them somewhere sensible: I made /var/lib/xen/boot and put them in there.
  3. Un-pause and Shutdown the virtual machine.
  4. Modify the config file, to include the paths to the xen-aware kernel and initrd (put these entries at the top, adjusting for your path as necessary): 
    kernel = "/var/lib/xen/boot/vmlinuz"
ramdisk = "/var/lib/xen/boot/initrd.img"

     

  5. IMPORTANT – also comment out the line for pygrub, so: = “/usr/bin/pygrub”
  6. Save the config and run the virtual machine. Nearly there!  Now open up the console to the virtual machine…
  • If you are prompted for a network address or DHCP, try DHCP.
  • If you are prompted for an installation path, stick to http. In a network interface dialog that may appear, choose a manual address that doesn’t conflict with other hosts on your real network (but make sure it’s valid for your network!!)
  • Because the VM now has a virtual network interface, http://localhost/centos is a meaningless path.  If the installer identifies this and prompts for an alternative path to the stage2.img file [true in CentOS, at least], then do the following on your host (real) machine:
    # ifconfig wlan0(substistute eth0 for wlan0 if you’re using a wired ethernet connection)
  • Paste/type the IP address from the output of ifconfig into the path dialog of the halted installer, but keep the /centos/ directory.

    • The installer should then run through the rest of the motions and voila – a paravirtualized virtual machine installed from local CD/DVD-ROM.

    When the installer has finished running, uncomment the pygrub line in the config file.

    If you spot any errors with this process, please let me know so I can correct the procedure.

    Happy Christmas!   *<(:-##

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