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How to create a Ubuntu root-file-system for VNX

Follow this procedure to create a Ubuntu based root-file-system for VNX. The procedure has been tested with Ubuntu 9.10 and 10.04.

  • Create the filesystem disk image:
  • qemu-img create -f qcow2 root_fs_ubuntu-base.qcow2 5GB
  • Get Ubuntu installation CD. For example:
  • wget
    cp ubuntu-10.04.1-server-i386.iso /almacen/iso
  • Create a libvirt XML definition (root_fs_ubuntu.xml) containing the virtual machine description:
  • <domain type='kvm'>
        <type arch="i686">hvm</type>
        <boot dev='hd'/>
        <boot dev='cdrom'/>
      <clock sync="localtime"/>
        <disk type='file' device='disk'>
          <source file='/usr/share/vnx/filesystems/root_fs_ubuntu-base.qcow2'/>
          <target dev='hda'/>
          <driver name="qemu" type="qcow2"/>
        <disk type='file' device='cdrom'>
          <source file='/almacen/iso/ubuntu-10.04.1-server-i386.iso'/>
          <target dev='hdb'/>
        <interface type='network'>
          <source network='default'/>
        <graphics type='vnc'/>

    Note: change "source file=" lines to whatever fits your case (use full paths).

  • Start the virtual machine with:
  • virsh create root_fs_ubuntu.xml
  • Access virtual machine console with:
  • virt-viewer Ubuntu

    Note: alternative you can start the machine and open the console at the same time with the command:

    /usr/share/vnx/bin/vnx_modify_rootfs root_fs_ubuntu.xml
  • Follow Ubuntu installation menus to install a basic system with ssh server. Once the installation is finished, stop the machine and edit root_fs_ubuntu.xml file and comment the following line in cdrom disk specification:
  •   <!--source file='/almacen/iso/ubuntu-10.04-server-i386.iso'/-->
  • Start the virtual machine again and finish the installation:
    • Access the console and sudo root:
    • sudo su
    • Update the system
    • apt-get update
      apt-get dist-upgrade
    • Install XML::DOM perl package and ACPI daemon:
    • apt-get install libxml-dom-perl acpid
    • Only for Ubuntu 10.04:
      • create /media/cdrom* directories:
      • mkdir /media/cdrom0
        mkdir /media/cdrom1
        ln -s /media/cdrom0 /media/cdrom
        ln -s /cdrom /media/cdrom
      • add the following lines to /etc/fstab:
      • /dev/scd0  /media/cdrom0    udf,iso9660  user,noauto,exec,utf8  0  0
        /dev/scd1  /media/cdrom1    udf,iso9660  user,noauto,exec,utf8  0  0
    • Configure a serial console on ttyS0:
    • cd /etc/init
      cp tty1.conf ttyS0.conf
      sed -i -e 's/tty1/ttyS0/' ttyS0.conf
    • Activate startup traces on serial console by editting /boot/grub/grub.cfg file and adding "console=ttyS0" to the linux line. For example:
    • linux   /boot/vmlinuz-2.6.35-25-generic-pae root=UUID=eb1a0afb-48b2-4e42-ba6d-22bfae1055f3 ro   quiet console=ttyS0
    • Install VNX autoconfiguration daemon:
      • From the host execute:
      • /usr/share/vnx/bin/vnx_update_aced Ubuntu /usr/share/vnx/aced/vnx-aced-lf-0.1b.tgz 
      • From the virtual machine console:
      • mount /media/cdrom
    • Delete udev rules files:
    • rm /etc/udev/rules.d/70-persistent-net.rules
      rm /etc/udev/rules.d/70-persistent-cd.rules
    • Optional: install graphical user interface.
      • Minimal:
      • sudo apt-get install xorg gnome-core gksu gdm gnome-system-tools gnome-nettool firefox-gnome-support
      • Complete:
      • sudo apt-get install ubuntu-desktop
    • Optional: install other services:
      • Apache server:
      • sudo apt-get install apache2
        update-rc.d -f apache2 remove   # to avoid automatic start
      • Other network tools
      • sudo apt-get install traceroute
    • Clean cache and stop the machine with:
    • apt-get clean

If everything went well, your root filesystem will be ready to be used with VNX. You can make a simple test using the simple_ubuntu.xml scenario distributed with VNX.

Installing additional software

To install additional software or modify your root file system, you just have to start it as described above and make the operations required on the filesystem.

  • Start the virtual machine (directly using virsh or the vnx_modify_rootfs utility):
 /usr/share/vnx/bin/vnx_modify_rootfs root_fs_ubuntu.xml 
  • Install the software:
apt-get install ...
  • Delete udev rules files:
rm /etc/udev/rules.d/70-persistent-net.rules
rm /etc/udev/rules.d/70-persistent-cd.rules
  • Stop the machine with:

Updating ACE daemon

If you have a root filesystem with the autoconfiguration and command execution daemon (ACE) already installed, you can use the autoupdate functionallity to update the daemon to a newer version. Just follow this procedure:

  • Edit the xml described above and comment the line defining the Ubuntu iso file for the cdrom:
  • Start the virtual machine (directly using virsh or the vnx_modify_rootfs utility):
 /usr/share/vnx/bin/vnx_modify_rootfs root_fs_ubuntu.xml 
  • Execute the update utility:
/usr/share/vnx/bin/vnx_update_aced Ubuntu /usr/share/vnx/aced/vnx-aced-lf-0.1b.tgz 
  • Once the ace daemon is updated the virtual machine will be rebooted automatically.

Known problems

  • Each a cdrom is mounted (for example, ehenever a command is executed on the virtual machine) the following error appear in the console:
  • Jul 27 22:33:31 vnx kernel: [ 4384.875886] ata1.01: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6
    Jul 27 22:33:31 vnx kernel: [ 4385.291374] ata1.01: BMDMA stat 0x5
    Jul 27 22:33:31 vnx kernel: [ 4385.493411] sr 0:0:1:0: [sr0] CDB: Read(10): 28 00 00 00 00 18 00 00 01 00
    Jul 27 22:33:31 vnx kernel: [ 4385.493460] ata1.01: cmd a0/01:00:00:00:08/00:00:00:00:00/b0 tag 0 dma 2048 in
    Jul 27 22:33:31 vnx kernel: [ 4385.493461]          res 01/60:00:00:00:08/00:00:00:00:00/b0 Emask 0x3 (HSM violation)
    Jul 27 22:33:31 vnx kernel: [ 4386.263553] ata1.01: status: { ERR }

    However, the command are executed correctly. This error does not appear on Ubuntu 9.10 filesystems.