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QemuNet

QemuNet is a light shell script based on QEMU and VDE to enable easy virtual networking.

Download & Install

QemuNet is a free software distributed under the terms of the GNU General Public License (GPL) and it is available for download at Inria GForge .

First of all, QemuNet requires to fulfill the following dependencies: 

$ sudo apt-get install qemu vde2 libattr1 libvirt0 socat

Moreover, one requires Bash version greater than or equal to 4.

QemuNet requires QEMU (qemu-system-x86_64) with VDE and KVM supports enabled and with a version greater than or equal to 2.1. Check it: 

$ qemu-system-x86_64 --version

Once all your dependencies are satisfied on your system, download it from SVN repository with anonymous access: 

$ svn checkout https://scm.gforge.inria.fr/anonscm/svn/qemunet/trunk qemunet

If the runtime commands required by QemuNet (qemu-system-x86_64, qemu-img and vde_switch) are not available in standard directory, you will need to edit the main script qemunet.sh.

Then you can launch a simple test based on a Linux TinyCore system. See README file for further details. 

$ ./qemunet.sh -t tinycore/lan4.topo

Then, you can start to play…

Examples

You will find several examples in the demo subdirectory. But, let's start with a basic LAN topology.

First, you need to prepare a virtual topology file, as for example demo/lan4.topo. It describes a LAN with 4 debian8 Virtual Machines (VM), named host1 to host4 and one Virtual Switch (VS) names s1. The debian8 system must refer to a valid system in the QemuNet configuration file qemunet.cfg.

lan4.topo
# SWICTH switchname
SWITCH s1
# HOST sysname hostname switchname0 switchname1 ...
HOST debian8 host1 s1
HOST debian8 host2 s1
HOST debian8 host3 s1
HOST debian8 host4 s1

Here is an example of the QemuNet configuration file qemunet.cfg. It requires to provide a valid Debian image for QEMU. Optionnaly, you will need to extract the kernel files (initrd & vmlinuz) from this image, as explained later. See below to know how to build his own debian image for QEMU.

qemunet.cfg
if [ -z "$IMGDIR" ] ; then IMGDIR="$(dirname $(realpath $0))" ; fi
# debian8
SYS[debian8]="linux"                              # system type (linux|windows|...)
FS[debian8]="$IMGDIR/images/debian8/debian.img"   # absolute path to raw system image for QEMU
QEMUOPT[debian8]="-localtime -m 512"              # qemu extra options
KERNEL[debian8]="$IMGDIR/images/debian8/vmlinuz"  # absolute path to system kernel (optionnal, only for linux)
INITRD[debian8]="$IMGDIR/images/debian8/initrd"   # absolute path to system initrd (optionnal, only for linux)

Following, you can launch your Virtual Network (VN). All the current session files are provided in the session directory, that is linked to a unique directory in /tmp. 

./qemunet.sh -t demo/lan4.topo

Once you have finish your work, halt all machines properly with “poweroff” command. Thus, you are sure that all VM disks are up-to-date.

If you want to restore your session from the current session directory, you can simply type: 

./qemunet.sh -S session

In order to save your session, you need to save all session files in a tgz archive. 

cd session ; tar cvzf lan4.tgz * ; cd ..

So, you will be able to restore your session later as follow: 

./qemunet.sh -s lan4.tgz

For instance, if you modify the system files of the VM host1, those modifications will not modify directly the raw system image debian.img (provided in qemunet.cfg), but it will store it the file session/host1.qcow2. By removing this file, you will restart the next session with the initial raw system image.

In addition, we use a “/etc/rc.local” script to load a user-defined script “/mnt/host/start.sh”, that is stored in the external session directory. It is a flexible way to setup each VM without modifying the raw system image or using the qcow2 files.

Manual

QemuNet is based on a single bash script qemunet.sh. Here are detailed available options: 

Start/restore a session:
  qemunet.sh -t topology [-a images.tgz] [...]
  qemunet.sh -s session.tgz [...]
  qemunet.sh -S session/directory [...]
Options:
    -t <topology>: network topology file
    -s <session.tgz>: session archive
    -S <session directory>: session directory
    -h: print this help message
Advanced Options:
    -a <images.tgz>: load a qcow2 image archive for all VMs
    -c <config>: load system config file (default is qemunet.cfg)
    -x: launch VM in xterm terminal instead of SDL native window (only for linux system)
    -y: launch VDE switch management console in xterm terminal
    -i: enable Slirp interface for Internet access (ping not allowed)
    -m: mount shared directory in /mnt/host (default for linux system)
    -q: ignore and remove qcow2 images for the running session
    -M: disable mount
    -v: enable VLAN support
    -k: enable KVM full virtualization support (default)
    -K: disable KVM full virtualization support (not recommanded)
    -l <sysname>: launch a VM in standalone mode to update its raw disk image

Configuration of QemuNet

Once you have download QemuNet, you need first to set the runtime commands for QEMU and VDE in qemunet.sh, if they don't use the default directory. 

QEMU="/usr/bin/qemu-system-x86_64"
QEMUIMG="/usr/bin/qemu-img"    
VDESWITCH="/usr/bin/vde_switch"

Then, you have to provide a configuration file that define several virtual systems and its parameters (name, type, disk image file, …). The default configuration file is qemunet.cfg. it is a bash script that uses associative arrays (bash 4 or greater required). For instance, the following file defines two linux systems called “debian8”, and one windows system called “winxp”.

qemunet.cfg
# template
# SYS[sysname]="linux|windows|..."
# FS[sysname]="/absolute/path/to/raw/system/image"
# QEMUOPT[sysname]="qemu extra options"
# KERNEL[sysname]="/absolute/path/to/system/kernel"  # optional, but useful for -x option
# INITRD[sysname]="/absolute/path/to/system/initrd"  # optional, but useful for -x option
 
# IMGDIR="/absolute/path/to/raw/system/images" 
if [ -z "$IMGDIR" ] ; then IMGDIR="$(dirname $(realpath $0))" ; fi
 
 
# tinycore 
SYS[tinycore]="linux"
FS[tinycore]="$IMGDIR/images/tinycore/linux-tinycore-linux-6.4-2.img"
QEMUOPT[tinycore]="-localtime -m 512"
 
# debian8
SYS[debian8]="linux"
FS[debian8]="$IMGDIR/images/debian8/debian.img"
QEMUOPT[debian8]="-localtime -m 512"
KERNEL[debian8]="$IMGDIR/images/debian8/vmlinuz"  # optional, but useful for -x option
INITRD[debian8]="$IMGDIR/images/debian8/initrd"   # optional, but useful for -x option
 
# winxp
SYS[winxp]="windows"
FS[winxp]="$IMGDIR/images/windows/winxp.img"
QEMUOPT[winxp]="-localtime -m 1G -usbdevice tablet"
 
# win10
SYS[win10]="windows"
FS[win10]="$IMGDIR/images/windows/win10.img"
QEMUOPT[win10]="-localtime -m 1G -usbdevice tablet"

The SYS and FS arrays are required for each system. They respectively define the system type (linux, windows, …) and the QEMU disk image file (in raw format). QEMUOPT can be used to pass additional options to QEMU when launching the VM, as for instance cpu type or max memory. See QEMU documentation for detailed options. Both KERNEL and INITRD are optional for linux system, but required if you want to launch the VMs in xterm (option -x).

How to Install my Own System for QEMU and QemuNet

Here are some testing QEMU images:

Follow the next tutorial to install your own Linux system for QemuNet…

Documentation

Other Solutions

qemunet/index.1473168295.txt.gz · Last modified: 2024/03/18 15:05 (external edit)