一台服务器可以虚拟几台主机

# 安装KVM和相关工具
sudo apt-get update
sudo apt-get install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils

# 创建虚拟机镜像
qemu-img create -f qcow2 ubuntu.qcow2 20G

# 定义虚拟机配置文件
cat <<EOF > ubuntu.xml
<domain type='kvm'>
  <name>ubuntu-vm</name>
  <memory unit='KiB'>2048000</memory>
  <currentMemory unit='KiB'>2048000</currentMemory>
  <vcpu placement='static'>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-2.9'>hvm</type>
    <boot dev='hd'/>
  </os>
  <devices>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/ubuntu.qcow2'/>
      <target dev='vda' bus='virtio'/>
    </disk>
    <interface type='network'>
      <mac address='52:54:00:73:3a:3f'/>
      <source network='default'/>
      <model type='virtio'/>
    </interface>
  </devices>
</domain>
EOF

# 定义并启动虚拟机
virsh define ubuntu.xml
virsh start ubuntu-vm