环境:
OS:Centos 7
1．想要对虚拟网卡virbr0网卡进行操作，首先要安装kvm虚拟化管理命令；
yum -y install libvirt virt-install qemu-kvm
2． 删除默认网络default
virsh net-destroy default
3． 取消定义网络default
virsh net-undefine default
4． 重启libvirtd服务生效
systemctl restart libvirtd.service
systemctl stop libvirtd.service #virbr0网卡取消后关闭libvirtd服务
systemctl disable libvirtd.service
5． 卸载步骤一安装的虚拟化管理命令,后面已经用不到了
yum -y remove libvirt virt-install qemu-kvm