Difference between revisions of "Vnx-rootfsubuntu"

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(Known problems)
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<li>Sometimes after restarting, the virtual machines stop at showing the grub menu and do not start until you manually choose one option. To avoid it, just follow the instructions here: http://www.linuxquestions.org/questions/linux-server-73/how-to-disable-grub-2-menu-even-after-server-crash-796562/ 
 +
</li>
 
<li>In Ubuntu 12.04 Desktop, graphical commands execution does not work. Command execution fails with "ERROR: no user logged on display :0.0" (see /var/log/vnxaced.log). If you just open a "terminal" window, commands work correctly (does not work if you open other applications; only when you start a terminal...).</li>
 
<li>In Ubuntu 12.04 Desktop, graphical commands execution does not work. Command execution fails with "ERROR: no user logged on display :0.0" (see /var/log/vnxaced.log). If you just open a "terminal" window, commands work correctly (does not work if you open other applications; only when you start a terminal...).</li>
 
<li>Each time a cdrom is mounted (for example, whenever a command is executed on the virtual machine) the following error appears in the console:</li>
 
<li>Each time a cdrom is mounted (for example, whenever a command is executed on the virtual machine) the following error appears in the console:</li>

Revision as of 18:05, 5 March 2013

How to create a KVM Ubuntu root filesystem for VNX

Basic installation

Follow this procedure to create a KVM Ubuntu based root filesystem for VNX. The procedure has been tested with Ubuntu 9.10, 10.04, 10.10, 11.04 and 12.04.

  • Create the filesystem disk image:
  • qemu-img create -f qcow2 vnx_rootfs_kvm_ubuntu.qcow2 8G
    
  • Get Ubuntu installation CD. For example:
  • wget ftp://ftp.rediris.es/mirror/ubuntu-releases/12.04/ubuntu-12.04-server-i386.iso
    cp ubuntu-12.04-server-i386.iso /almacen/iso
    

    Note: use 'server' or 'desktop' CD versions depending on the system you want to create.

  • Create the virtual machine with:
  • vnx --create-rootfs vnx_rootfs_kvm_ubuntu.qcow2 --install-media /almacen/iso/ubuntu-12.04-server-i386.iso --mem 512M
    
  • Follow Ubuntu installation menus to install a basic system with ssh server.
  • 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 /etc/default/grub file and setting the GRUB_CMDLINE_LINUX_DEFAULT variable to "console=ttyS0". Also change the boot menu timeout to 0 (sometimes virtual machines get stopped on the boot menu when starting on high loaded systems):
  • GRUB_CMDLINE_LINUX_DEFAULT="console=ttyS0"
    GRUB_TIMEOUT=0
    
  • Make grub process the previous changes:
  • update-grub
    
  • Finally, delete the net udev rules file and halt the system:
  • rm /etc/udev/rules.d/70-persistent-net.rules
    halt -p
    

Configuration

  • Restart the system with the following command:
  • vnx --modify-rootfs vnx_rootfs_kvm_ubuntu.qcow2 --update-aced --mem 512M
    

    Note: ignore the errors "timeout waiting for response on VM socket". 768M are needed if you are installing a root filesystem with desktop interface

  • Access the system through the text console to easy the copy-paste of commands:
  • virsh console vnx_rootfs_kvm_ubuntu.qcow2
    
  • 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-libxml-perl acpid
    
  • Install VNX autoconfiguration daemon:
  • mount /dev/sdb /mnt/
    perl /mnt/vnxaced-lf/install_vnxaced
    
  • Edit /etc/network/interfaces file and comment all lines related to eth0, eth1, etc interfaces. Leave only the loopback (lo) interface.
  • 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
      

      Note: to avoid nautilus being launched any time you remotely execute a command on the virtual machine using VNX (which interferes with the normal execution of commands), you should disable the start of programs when media insertion takes place. Go to "System settings->System->Details->Removable Media" and deselect the checkbox "Never prompt or start programs on media insertion".

  • 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
      
  • Create a file /etc/vnx_rootfs_version to store version number and informacion about modification:
  • VER=v0.24
    OS=Ubuntu 12.04
    DESC=basic Ubuntu 12.04 root-file-system without GUI
    
  • Stop the machine with vnx_halt:
  • vnx_halt
    

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 to modify your root file system, you just have to:

  • Start a virtual machine from it:
  • vnx --modify-rootfs vnx_rootfs_kvm_ubuntu.qcow2
    
  • Check network connectivity. Maybe you have to activate the network interface by hand:
  • dhclient eth0
    

    Note: use "ip link show" to know which network interface to use.

  • Do the modifications you want.
  • Finally, halt the system using:
  • vnx_halt
    

Examples

  • dhcp server and relay:
    • Install dhcp3 packages:
    • apt-get install dhcp3-server dhcp3-relay
      
    • Disable autostart (optional):
    • update-rc.d -f isc-dhcp-server remove
      update-rc.d -f isc-dhcp-relay remove
      


Updating VNXACED

You can automatically update the VNXACE daemon with the following command:

vnx --modify-rootfs vnx_rootfs_kvm_ubuntu.qcow2 --update-aced -y

If VNXACE daemon is not updated automatically, you can do it manually by accessing the virtual machine console and type:

mount /dev/sdb /mnt/
perl /mnt/vnxaced-lf/install_vnxaced

Known problems

  • Sometimes after restarting, the virtual machines stop at showing the grub menu and do not start until you manually choose one option. To avoid it, just follow the instructions here: http://www.linuxquestions.org/questions/linux-server-73/how-to-disable-grub-2-menu-even-after-server-crash-796562/
  • In Ubuntu 12.04 Desktop, graphical commands execution does not work. Command execution fails with "ERROR: no user logged on display :0.0" (see /var/log/vnxaced.log). If you just open a "terminal" window, commands work correctly (does not work if you open other applications; only when you start a terminal...).
  • Each time a cdrom is mounted (for example, whenever a command is executed on the virtual machine) the following error appears 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 }
    

    Despite of the error trace, the commands are executed correctly. This error does not appear on Ubuntu 9.10 filesystems.