Prepare host system for virtual machines, this includes create new user, loading necessary modules and configure network. Load kvm module, in this example intel module is loaded but depends on host cpu;
# modprobe -a kvm-intel tun virtio
Add users to kvm group;
# usermod -a -G kvm c9admin
# usermod -a -G kvm username
Qemu supports multiple disk images types.
Create hard disk image, there is different types, this describes how to create a qcow2 type;
$ qemu-img create -f qcow2 crux-img.qcow2 2000M
Qemu disk images can be treated as regular disks using qemu disk network block device server;
$ sudo modprobe nbd
$ sudo qemu-nbd -c /dev/nbd0 /crux-img.qcow2
Information about preparing partitions and storage administration. You can use image as a normal disk, example how to use parted to create a gpt system table;
parted --script ${DEV} \
mklabel gpt \
unit mib \
mkpart primary 2 4 \
set 1 bios_grub on \
name 1 grub \
mkpart ESP fat32 4 59 \
set 2 boot on \
name 2 efi \
mkpart primary ext4 103 200 \
name 3 boot \
mkpart primary linux-swap 200 456 \
name 4 swap \
mkpart primary ext4 456 3700 \
name 5 root \
mkpart primary ext4 3700 4000 \
name 6 var \
mkpart primary ext4 4000 100% \
name 7 home
# kpartx -a -s -l -u /dev/nbd0
Use /dev/mapper/$(name_of_device) to assign correct blocks;
mkfs.fat -F 32 /dev/mapper/${DEV_NAME}p2
mkfs.ext4 /dev/mapper/${DEV_NAME}p3
mkswap /dev/mapper/${DEV_NAME}p4
mkfs.ext4 /dev/mapper/${DEV_NAME}p5
mkfs.ext4 /dev/mapper/${DEV_NAME}p6
mkfs.ext4 /dev/mapper/${DEV_NAME}p7
Mount partition;
mount /dev/mapper/${DEV_NAME}p5 $CHROOT
mkdir -p $CHROOT/proc
mkdir -p $CHROOT/sys
mkdir -p $CHROOT/dev
mkdir -p $CHROOT/boot
mount /dev/mapper/${DEV_NAME}p3 $CHROOT/boot
mkdir -p $CHROOT/boot/efi
mount /dev/mapper/${DEV_NAME}p2 $CHROOT/boot/efi
mkdir -p $CHROOT/var
mount /dev/mapper/${DEV_NAME}p6 $CHROOT/var
mkdir -p $CHROOT/home
mount /dev/mapper/${DEV_NAME}p7 $CHROOT/home
Before disconnecting image, clean dev mappings;
$ sudo kpartx -d /dev/nbd0
$ sudo qemu-nbd -d /dev/nbd0
Network configuration;
KERNEL=="tun", GROUP="kvm", MODE="0660", OPTIONS+="static_node=net/tun"
Create interface with correct permissions set for kvm group.
# sysctl -w net.ipv4.ip_forward=1
# iptables -A INPUT -i br0 -j ACCEPT
# iptables -A FORWARD -i br0 -j ACCEPT
# iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -d 10.0.0.0/24 -j ACCEPT
# iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -j MASQUERADE
Create bridge, create new tap and add it to bridge;
DEV="br0"
ADDR=10.0.0.254
NET=10.0.0.0
GW=192.168.1.254
MASK=24
# one tap for each cpu core
NTAPS=$((`/usr/bin/nproc`))
case $1 in
start)
/sbin/ip link add name ${DEV} type bridge
/sbin/ip addr add ${ADDR}/${MASK} dev ${DEV} broadcast +
/sbin/ip link set dev ${DEV} up
/bin/sleep 0.2s
for i in `/usr/bin/seq $NTAPS`
do
TAP="tap$i"
echo "Setting up ${TAP} tap interface."
/sbin/ip tuntap add ${TAP} mode tap group kvm
/sbin/ip link set ${TAP} up
/bin/sleep 0.2s
/sbin/ip link set ${TAP} master ${DEV}
done
exit 0
;;
stop)
for i in `/usr/bin/seq $NTAPS`
do
TAP="tap$i"
echo "Deleting ${TAP} tap interface."
/sbin/ip link del ${TAP}
done
/sbin/ip link set dev ${DEV} down
/sbin/ip route flush dev ${DEV}
/sbin/ip link del ${DEV}
exit 0
;;
restart)
$0 stop
$0 start
;;
*)
echo "Usage: $0 [start|stop|restart]"
;;
esac
# End of file
See scripts/runvm/runvm.sh, as template. Example scripts;
runvm/profile/crux
mac=$(rmac_addr)
memory=1024
boot=d
tap="tap1"
iso=iso/crux-3.3.iso
image=img/crux-standard.qcow2
other="-vga std -display sdl"
runvm/runvm.sh
function rmac_addr (){
printf '54:60:BE:EF:%02X:%02X\n' $((RANDOM%256)) $((RANDOM%256))
}
source profile/$1
qemu-system-x86_64 \
-enable-kvm \
-m ${memory} \
-boot ${boot} \
-cdrom ${iso} \
-hda ${image} \
-device e1000,netdev=t0,mac=${mac} \
-netdev tap,id=t0,ifname=${tap},script=no,downscript=no \
${other} \
&
Set guests machines to run under the total resolution provided by host system configure grub on the guest with gfxmode;
Get current resolution on host machine;
$ xrandr --current | fgrep '*'
1366x768 60.00*+
Set grub gfxmod on guest machine, edit /etc/default/grub;
GRUB_GFXMODE=1366x768
GRUB_GFXPAYLOAD_LINUX=keep
Update grub configuration on guest machine;
# update-grub
Check if DMAR is enable on kernel configuration, Intel and AMD uses different technology. To check on Inter machine run;
# grep -e DMAR -e IOMMU
runvm/profile/crux
export QEMU_AUDIO_DRV=alsa
memory=1024
boot=c
iso=iso/devuan_jessie_1.0.0_amd64_CD.iso
image=img/c12-dvd.qcow2
tap="tap2"
mac="54:60:be:ef:5c:72"
other="-soundhw hda -vga std -display sdl"
# lsusb
# ls /dev/v4l
# ls /dev/bus/usb
# chown root:kvm /dev/bus/usb/003/004
export QEMU_AUDIO_DRV=alsa
memory=1024
boot=c
iso=iso/devuan_jessie_1.0.0_amd64_CD.iso
image=img/c12-dvd.qcow2
tap="tap2"
mac="54:60:be:ef:5c:72"
other="-soundhw hda -vga std -display sdl -usb -device usb-host,vendorid=0x13d3,productid=0x5652"
# lsusb
# ls /dev/bus/usb
# chown root:kvm /dev/bus/usb/003/012
$ qemu-system-x86_64 -m 512 -enable-kvm -vnc :0 -usb -device usb-host,hostbus=3,hostaddr=12
Tools Index
This is part of the c9 Manual. Copyright (C) 2018 c9 team. See the file Gnu Free Documentation License for copying conditions.