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Windows VM in KVM/QEMU on headless Ubuntu server
without using libvirt
install kvm
apt-get install kvm qemu
now create a disk image
qemu-img create -f raw /vm/windows.img 100G
(note: creating a raw image has severale advantages: if your filesystem supports sparse files, it only uses the actually used space of your virtual disk on your physical disk.. all journalling filesystems that use inodes support that, so ext4 for example works fine. second you can easily mount it using mount -o loop <imgfile> <mountpoint> at any time. however, it does not support snapshots, use qcow2 if you need snapsots or if your filesystem does not support sparse files)
in my case i had a windows 7 cd that i installed from.. if your server dos not have a cd rom you can also us an iso image instead.
since I want to use virtio for fast hdd emulation, we also need the virtio drivers
cd /vm wget https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso
run qemu and install windows. access the display via VNC
qemu-system-x86_64 -enable-kvm -k de-ch -name windows -vnc :1 -cdrom /dev/cdrom -boot d -drive file=/vm/windows.img,if=virtio,format=raw,index=0 -m 4096
now connect with your favourite vnc client to the ip of your server and install windows. you need to load the derivers from the second cdrom that is emulated. make sure you choose the correct virtio storage driver for your windows version. it may load the wrong one if you just select the root directory and let the installer search for it, resulting in an unstable windows vm
autostart on boot / init script
once the installation is done, shut down your windows vm. it is now time to make it autostart upon boot of your linux machine.. in order to do that i used Thomas Martin's kvm-simple-init of which i keep a local copy (dated 2016-01-23)
this script will also send a shutdown command to all vms once the server shuts down, so no need to manually do that in order to gracefully shutdown your vm's
bridged network
by default qemu uses nat-ed network, so that the vm is in its own network and the vm host acts as a nat router. if you want your vm to be part of your network like any physical machine you have connected to your swich you can use a bridged connection..
you need to install bridge-utils to be able to create a bridge network device
apt-get install bridge-utils
now change your /etc/network/scripts
file and basically replace eth0 with br0 and then add three lines for the bridge config. here the end result on mine:
<code>
auto br0
iface br0 inet static
address 192.168.168.1 netmask 255.255.255.0 network 192.168.168.0 broadcast 192.168.168.255 gateway 192.168.168.254 bridge_ports eth0 bridge_stp off bridge_maxwait 5
<code> Notice: you won't need any block for eth0 after you defined the bridge interface.
now either reboot your machine or try to get your eth0 down using ifconfig
and then get br0 up using ifup
however be careful when you are doing this all remoetely!! in that case make really really sure you got your config right or even better, setup a backdoor, make sure your remote management module is accessible, whatever.. and then reboot your server.. and hope :)
now in your qemu command line you ened to add the parameters
- net nic -net tap
the default qemu-ifup script in /etc/ will do the rest for you.