Vnx-examples

VNX Example Scenarios

Several example scenarios are distributed together with VNX to allow easily testing its functionalities (see /usr/share/vnx/examples directory).

Three types of scenarios are included:

• simple-XXXX.xml, which are a set of simple scenarios made of one virtual machine with one network interface.
• simple_uml.xml: a single Linux virtual machine started using UML with address 10.0.0.2
• simple_xp.xml: a single Windows XP virtual machine started using libvirt with address 10.0.0.3
• simple_win7.xml: a single Windows 7 virtual machine started using libvirt with address 10.0.0.4
• simple_ubuntu.xml: a single Ubuntu 10.04.1 server virtual machine started using libvirt with address 10.0.0.5
• simple_ubuntu-gui.xml: a single Ubuntu 10.04.1 virtual machine with a minimal GNOME gui started using libvirt with address 10.0.0.6
• simple_freebsd.xml: a single FreeBSD 8.1 server virtual machine started using libvirt with address 10.0.0.7
• simple_freebsd-gui.xml: a single FreeBSD 8.1 virtual machine with a minimal GNOME gui started using libvirt with address 10.0.0.8

All scenarios share the same network (Net0, 10.0.0.0/24) to allow connectivity among all the virtual machines and the host (which has address 10.0.0.1)

• tutorial_root1-XXXX.xml, which are virtual scenarios based on the VNUML tutorial scenario but starting virtual machines using other operating systems.
• root_fs_XXX.xml, which are libvirt specifications to start virtual machines with Internet connection (through a NAT) using the different VNX root file-systems. They are included to easily allow modifying root filesystems (for example, to install new software packages).

To test the scenarios:

• Open a root shell from the graphical console of the host machine. If you are not sat in front of host's console you can access it using ssh with X-forwarding activated. For example, from a Unix machine you can use:

  ssh -X <host-addr>

In this case, it is recommended to test that X-forwarding is working by launching a "xterm" or "xeyes" application and seeing that the application window is correctly launched. Besides, as the access to the virtual machine consoles is tipically made using virt-viewer application (VNC protocol), you need a good connectivity between your machine and the host were VNX runs.

Simple scenarios (simple_XXXX.xml)

• Start simple scenarios by means of:

vnx -f /usr/share/vnx/examples/simple_XXXX.xml -v -u root --create

For example, to start an XP virtual machine type:

vnx -f /usr/share/vnx/examples/simple_xp.xml -v -u root --create

Just after the execution, you will see the console of the Windows XP machine starting. Once the machine has completely started, the VNX autoconfiguration daemon will configure its name and the network interfaces and restart the machine for the changes to take effect. After the restart, the virtual machine will be available for interacting with it.

Note: virt-viewer console application "captures" the mouse when interacting with the virtual machines. You have to type "Ctrl-Alt" to release the mouse.

• Once started, you can test the network connectivity form the host to the virtual machine:

  root@tutatis:/usr/share/vnx/examples# ping -c 4 10.0.0.3
  PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.
  64 bytes from 10.0.0.3: icmp_seq=1 ttl=128 time=0.312 ms
  64 bytes from 10.0.0.3: icmp_seq=2 ttl=128 time=0.376 ms
  64 bytes from 10.0.0.3: icmp_seq=3 ttl=128 time=0.249 ms
  64 bytes from 10.0.0.3: icmp_seq=4 ttl=128 time=0.260 ms
  
  --- 10.0.0.3 ping statistics ---
  4 packets transmitted, 4 received, 0% packet loss, time 2999ms
  rtt min/avg/max/mdev = 0.249/0.299/0.376/0.051 ms
  

• You can also execute commands on the virtual machine from the host. For example, you can start the calculator on the Windows XP machine by issuing:

vnx -f /usr/share/vnx/examples/simple_xp.xml -v -u root --exe calc

This command has been specified inside the simple_xp.xml file in the line:

<exec seq="calc" type="verbatim" mode="system">calc.exe</exec>

Note: the previous command does not end till you close the calc application.

You can also copy a text file from the host to the virtual machine and show it using Notepad by issuing:

vnx -f /usr/share/vnx/examples/simple_xp.xml -v -u root --exe vnxtxt

This command is specified using the following two lines:

<filetree seq="vnxtxt" root="c:\temp">conf/txtfile</filetree>
<exec seq="vnxtxt" type="verbatim" mode="system">start /max notepad c:\temp\vnx.txt</exec>

• You can start a Linux Ubuntu server with:

vnx -f /usr/share/vnx/examples/simple_ubuntu.xml -v -u root --create

And start a web server inside it with:

vnx -f /usr/share/vnx/examples/simple_ubuntu.xml -v -u root --exe start-www

And test the web server access from the XP virtual machine by manually opening a web navigator and loading URL http://10.0.0.4.

• You can find more example commands by having a look at all simple_XXXX.xml files.
• To stop the scenario preserving the changes made:

vnx -f /usr/share/vnx/examples/simple_xp.xml -v -u root --shutdown

• To stop the scenario discarding the changes made:

vnx -f /usr/share/vnx/examples/simple_xp.xml -v -u root --destroy

Tutorial scenarios (tutorial_root1_XXXX.xml)

• To start the tutorial scenario with linux and XP machines just type:

vnx -f tutorial_root1_xp.xml -v -u root --create

• Once the scenario has completely started (remenber that the XP machines have to be restarted for the autoconfiguration to complete), you can test the network connectivity, for example, accesing uml1 machine and tracing to uml5: traceroute -n 10.0.2.2
• Para parar y rearrancar una máquina concreta sin perder las modificaciones realizadas: vnx -d examples/tutorial_root1_xp.xml -v -u root -M uml4 vnx -t examples/tutorial_root1_xp.xml -v -u root -M uml4
• Para parar y rearrancar una máquina concreta creando una copia nueva desde el rootfs original: vnx -P examples/tutorial_root1_xp.xml -v -u root -M uml4 vnx -t examples/tutorial_root1_xp.xml -v -u root -M uml4

Modify root filesystem scenarios (root_fs_XXX.xml)

To modify a root filesystem, for example, installing new software packages, just start the associated libvirt scenario with:

virsh create root_fs_XXX.xml

And open the console using:

virt-viewer VMNAME

being VMNAME the name assigned to the virtual machine (you can get it with "virsh list" command or just looking for the <name> tag in root_fs_XXX.xml file).

To easy the process, you can use the following script that starts the virtual machine and opens the console:

#/bin/bash

XMLFILE=$1
echo $XMLFILE
# Find tag in the xml, convert tabs to spaces, remove leading spaces, remove the tag.
VMNAME=$( grep "<name>" $XMLFILE | \
        tr '\011' '\040' | \
        sed -e 's/^[ ]*//' \
            -e 's/^<.*>\([^<].*\)<.*>$/\1/' )
echo Starting $VMNAME virtual machine
virsh create $XMLFILE && virt-viewer $VMNAME &

Just copy the previous script to a file named vnx_modify_rootfs (or whatever you want) and invoke it with:

vnx_modify_rootfs root_fs_XXX.xml