Vnx-rootfsubuntu-draft

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

Basic installation

Follow this procedure to create a Ubuntu based root-file-system 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 8GB

• 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

Configuration

• 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

• 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
/media/cdrom/install_vnxdaemon

• 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

• 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 that script:

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

• Start a VM with the root filesystem using virsh:

virsh create rootfs_ubuntu.xml 
virt-viewer Ubuntu

• Or alternatively using vnx_modify_rootfs:

vnx_modify_rootfs /usr/share/vnx/filesystems/vnx_rootfs_kvm_ubuntu-base.qcow2

• From inside the VM install the software desired:

apt-get install ...

• Stop the machine with:

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 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 rootfs_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 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.