centos 7 kvm 安装centos6.8

yum groupinstall "X Window System" "GNOME Desktop" –y
systemctl set-default graphical.target
reboot
egrep -o '(vmx|svm)' /proc/cpuinfo
yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python python-virtinst libvirt- client virt-install virt-viewer -y
systemctl enable libvirtd --now
lsmod | grep -i kvm

brctl show
virsh net-list
virsh net-dumpxml default
vi /etc/sysconfig/network-scripts/ifcfg-ens33
BRIDGE=br0
vi /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE="br0"
# I am getting ip from DHCP server #
BOOTPROTO="dhcp"
ONBOOT="yes"
TYPE="Bridge"
DELAY="0"
systemctl restart NetworkManager
brctl show
mount /dev/sr0 /mnt
dd if=/dev/sr0 of=/centos68.iso

virt-install --name=centos6.8 --ram=1024 --vcpus=1 --cdrom=/centos68.iso --os-type=linux --os-variant=centos6.8 --network bridge=br0 --graphics=spice --disk path=/var/lib/libvirt/images/centos68.dsk,size=4