create vm script on centos7.9
virt-install \
--virt-type=kvm \
--name centos7 \
--ram 2048 \
--vcpus=1 \
--os-variant=centos7.0 \
--cdrom=/root/CentOS-7-x86_64-Minimal-2009.iso \
--network=bridge=br0,model=virtio \
--graphics vnc \
--disk path=/var/lib/libvirt/images/centos7.qcow2,size=10,bus=virtio,format=qcow2