python 使用libvirt 接口创建虚拟机

import libvirt
import uuid
import random
import ipaddress
import shutil
import os

class KVMManager:
    def __init__(self):                                     # 定义类的引用self接口:  __init__ 内置初始化函数 被自定义名字 self 继承; 自定执行，不需要在其它函数调用
        self.conn = self.connect_to_libvirt()               # 定义:  self 的属性成员 conn  的表达方式 由 connect_to_libvirt 函数里面定义得来 
                                                            # 下次使用 self.conn 函数为初始化链接 qemu 

    def connect_to_libvirt(self):
        try:                                                # try 代码块 用于捕获可能发生的异常
            conn = libvirt.open('qemu:///system')
            if conn is None:
                raise Exception('Failed to connect to hypervisor')
                                                            # raise 关键字: 抛出异常， 异常的方法 Exception 是一个字符串
            return conn                                     # 如果连接成功，返回连接对象 conn，赋值给 self.conn
        except libvirt.libvirtError as e:                   # except 捕捉异常并处理它；libvirt 是kvm虚拟化api模块；libvirtError  异常类: 错误信息变量
            print(f'Connection failed: {e}')
            exit(1)                                         # 程序退出的条件是 出现异常1  判断的是  当前代码块 except libvirt.libvirtError as e

    def generate_mac(self):
        """Generate a random MAC address."""
        mac = [0x52, 0x54, 0x00] + [random.randint(0x00, 0x7f) for _ in range(3)]
        return ':'.join(map(lambda x: f'{x:02x}', mac))

    def generate_ip(self, subnet):
        """Generate a random IP address in the given subnet."""
        network = ipaddress.ip_network(subnet, strict=False)
        return str(random.choice(list(network.hosts())))

    def ensure_dir_exists(self, directory):
        """Ensure that the directory exists, creating it if necessary."""
        if not os.path.exists(directory):
            os.makedirs(directory)

    def copy_image(self, source_path, dest_dir, new_name):
        """Copy the VM image to the destination directory with a new filename."""
        self.ensure_dir_exists(dest_dir)
        destination_path = os.path.join(dest_dir, new_name)
        try:
            shutil.copy(source_path, destination_path)
            print(f'Image copied to {destination_path}')
            return destination_path
        except IOError as e:
            print(f'Failed to copy image: {e}')
            return None

    def create_vm(self, name, memory, vcpu, source_image_path, subnet):
        dest_dir = '/datadisk/vm/pyauto'
        new_filename = 'debian12-01.qcow2'
        destination_image_path = self.copy_image(source_image_path, dest_dir, new_filename)
        if destination_image_path is None:
            print(f'Failed to copy image. VM creation aborted.')
            return
        
        mac_address = self.generate_mac()
        ip_address = self.generate_ip(subnet)
        xml_config = f"""
        <domain type='kvm'>
          <name>{name}</name>
          <memory unit='KiB'>{memory}</memory>
          <vcpu placement='static'>{vcpu}</vcpu>
          <os>
            <type arch='x86_64' machine='pc-i440fx-2.9'>hvm</type>
          </os>
          <devices>
            <disk type='file' device='disk'>
              <driver name='qemu' type='qcow2'/>
              <source file='{destination_image_path}'/>
              <target dev='vda' bus='virtio'/>
              <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
            </disk>
            <interface type='network'>
              <mac address='{mac_address}'/>
              <source network='default'/>
              <model type='virtio'/>
              <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
            </interface>
            <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'/>
          </devices>
          <metadata>
            <network>
              <ip address='{ip_address}' netmask='255.255.255.0'/>
            </network>
          </metadata>
        </domain>
        """
        try:
            self.conn.defineXML(xml_config)
            print(f'VM {name} created successfully with MAC {mac_address} and IP {ip_address}')
        except libvirt.libvirtError as e:
            print(f'Failed to create VM: {e}')

    def start_vm(self, name):
        try:
            vm = self.conn.lookupByName(name)
            vm.create()
            print(f'VM {name} started successfully')
        except libvirt.libvirtError as e:
            print(f'Failed to start VM: {e}')

    def stop_vm(self, name):
        try:
            vm = self.conn.lookupByName(name)
            vm.shutdown()
            print(f'VM {name} shutdown request sent')
        except libvirt.libvirtError as e:
            print(f'Failed to stop VM: {e}')

    def delete_vm(self, name):
        try:
            vm = self.conn.lookupByName(name)
            vm.undefine()
            print(f'VM {name} deleted successfully')
        except libvirt.libvirtError as e:
            print(f'Failed to delete VM: {e}')

    def list_vms(self):
        try:
            vms = self.conn.listAllDomains()
            for vm in vms:
                print(f'VM Name: {vm.name()}')
        except libvirt.libvirtError as e:
            print(f'Failed to list VMs: {e}')

    def close(self):
        self.conn.close()

if __name__ == '__main__':
    manager = KVMManager()
    # 示例操作
    manager.create_vm('test-vm', '2048000', '2', '/datadisk/myfolder/iso/qcow2/linux/debian12-username-eisc-000000.qcow2', '192.168.122.0/24')
    manager.start_vm('test-vm')
    manager.list_vms()
    manager.stop_vm('test-vm')
    manager.delete_vm('test-vm')
    manager.close()


'''
python312 -m pip install --upgrade pip         # 更新pip 安装工具
pip install libvirt-python                     # 安装kvm api 库
'''