qemu-scripts

Shell scripts for managing qemu/kvm VMs.

Usage

All of the scripts look for config.vm in the current directory. config.vm is a shell script which sets a number of environment variables which effect how the scripts run. At a minimum config.vm must contain ID=## where ## is a positive integer which uniquely identifies the VM in the host system.

• startVM - Starts the VM.
• connectVM - Opens a display to a running VM using spicy.
• mountVM - Mounts the directory mnt using to the root of a Windows VM using sshfs.

Setup

startVM uses vde2 for networking. To configure first install the following pacakges:

sudo apt-get install -y vde2 dnsmasq qemu-kvm qemu-utils

Then add the following to /etc/network/interfaces.

auto vmtap
iface vmtap inet static
  address 10.1.3.1
  netmask 255.255.255.0
  vde2-switch -t vmtap

Create /etc/dnsmasq.d/vm.conf with:

interface=vmtap
listen-address=10.1.3.1
dhcp-range=vmtap,10.1.3.2,10.1.3.253,12h
dhcp-host=02:00:00:00:00:00,10.1.3.10
dhcp-host=02:00:00:00:00:01,10.1.3.11
dhcp-host=02:00:00:00:00:02,10.1.3.12
dhcp-host=02:00:00:00:00:03,10.1.3.13
dhcp-host=02:00:00:00:00:04,10.1.3.14
dhcp-host=02:00:00:00:00:05,10.1.3.15
dhcp-host=02:00:00:00:00:06,10.1.3.16
dhcp-host=02:00:00:00:00:07,10.1.3.17
dhcp-host=02:00:00:00:00:08,10.1.3.18
dhcp-host=02:00:00:00:00:09,10.1.3.19
dhcp-host=02:00:00:00:00:10,10.1.3.20
dhcp-host=02:00:00:00:00:11,10.1.3.21
dhcp-host=02:00:00:00:00:12,10.1.3.22
dhcp-host=02:00:00:00:00:13,10.1.3.23
dhcp-host=02:00:00:00:00:14,10.1.3.24
dhcp-host=02:00:00:00:00:15,10.1.3.25
dhcp-host=02:00:00:00:00:16,10.1.3.26
dhcp-host=02:00:00:00:00:17,10.1.3.27
dhcp-host=02:00:00:00:00:18,10.1.3.28
dhcp-host=02:00:00:00:00:19,10.1.3.29
dhcp-host=02:00:00:00:00:20,10.1.3.30
dhcp-host=02:00:00:00:00:21,10.1.3.31

Start vde2 and dnsmasq.

sudo ifup vmtap
sudo service dnsmasq start

Allow VMs to access external network

You will need IP address masquerading to allow the VMs to access the external network. This can be accomplished with:

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o vmtap -m state \
  --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -A FORWARD -i vmtap -o eth0 -j ACCEPT

Where eth0 is the external network interface.

To have this firewall configuration automatically restored on reboot install iptables-persistent.

sudo apt-get install -y iptables-persistent

Save the firewall rules with:

sudo iptables-save | sudo tee /etc/iptables/rules.v4

Also make sure forwarding is enabled.

sudo sysctl -w net.ipv4.ip_forward=1

To make this configuration permanent add net.ipv4.ip_forward = 1 to /etc/sysctl.conf and save the firewall configuration.