前言

先前的例子在代码中指定数据中心、主机、虚拟机的参数，如：ram、bw、storage、mips、PEs等，非常混乱。通过改进，实现从XML配置文件读取数据来创建，实现数据与逻辑分类，使之更加直观。

配置文件

通过抽象，将一个数据中心（datacenter）描述成如下配置文件。

datacenters.xml

<?xml version="1.0"?>
<datacenters>
	 <datacenter arch="x86" os="Linux" >
		<hosts>
			<host>
				<core>4</core>				<!-- in number of Processing Elements(PEs)  -->
				<mips>8000</mips>			<!-- Million Instructions Per Second (MIPS) -->
				<ram>1600</ram>  			<!-- in Megabytes -->
				<storage>20000</storage>  	<!-- in Megabytes -->
				<VMs>
					<VM>
						<core>1</core>
						<mips>1000</mips>
						<ram>400</ram>
						<storage>2000</storage>
					</VM>
					<VM>
						<core>1</core>
						<mips>1000</mips>
						<ram>400</ram>
						<storage>2000</storage>
					</VM>
					<VM>
						<core>2</core>
						<mips>5000</mips>
						<ram>800</ram>
						<storage>4000</storage>
					</VM>
				</VMs>
			</host>
		</hosts>
	</datacenter>
</datacenters>

关于主机的带宽参数，虚拟机的CPU调度策略等，可以写到另外的配置文件中。

DatacenterParameters.java

public class DatacenterParameters {
	public static int WAN_BANDWIDTH = 300;      // bandwidth (in Megabits/s)
	// CloudletSpaceShared，Cloudlet所需的PE将被独有地安排。
	// 这意味着如果Cloudlet数量大于可用的PE数量，后面到达的Cloudlet将在队列中等待，直到有足够的空闲资源。
	public static String CPU_ALLOCATION_POLICY = "SPACE_SHARED";
}

解析数据

同一数据中心的主机（host）分配相同的带宽，也即配置文件中的WAN_BANDWIDTH。
同一台主机上的虚拟机上均分带宽，也即：long vmBandwidth = bandwidth / vmNodeList.getLength();。
在创建虚拟机时将虚拟机绑定到所属的主机上。

/**
 * @Author: mhh
 * @Date: 2021/8/9
 * @Description: 通过XML配置文件创建数据中心
 */
public class DatacentersManager {

    private final List<DatacenterSimple> datacentersList;
    private final List<Vm> vmList;
    private final CloudSim simulation;

    public DatacentersManager(CloudSim simulation) {
        this.simulation = simulation;
        this.datacentersList = new ArrayList<>();
        this.vmList = new ArrayList<>();
    }

    public void createDataCenters(String file) throws Exception {
        File serversFile = new File(file);
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(serversFile);
        NodeList datacenterList = doc.getElementsByTagName("datacenter");
        for (int i = 0; i < datacenterList.getLength(); i++) {
            Node datacenterNode = datacenterList.item(i);
            Element datacenterElement = (Element) datacenterNode;
            // 创建主机列表
            List<Host> hostList = createHosts(datacenterElement);
            // 创建数据中心
            datacentersList.add(new DatacenterSimple(simulation, hostList));
        }
    }

    private List<Host> createHosts(Element datacenterElement) {

        List<Host> hostList = new ArrayList<>();

        NodeList hostNodeList = datacenterElement.getElementsByTagName("host");
        for (int j = 0; j < hostNodeList.getLength(); j++) {

            Node hostNode = hostNodeList.item(j);
            Element hostElement = (Element) hostNode;
            int numOfCores = Integer.parseInt(hostElement.getElementsByTagName("core").item(0).getTextContent());
            double mips = Double.parseDouble(hostElement.getElementsByTagName("mips").item(0).getTextContent());
            long storage = Long.parseLong(hostElement.getElementsByTagName("storage").item(0).getTextContent());
            long ram = Integer.parseInt(hostElement.getElementsByTagName("ram").item(0).getTextContent());
			
			long bandwidth =  SimulationParameters.WAN_BANDWIDTH;
			
            List<Pe> peList = new ArrayList<>();

            for (int i = 0; i < numOfCores; i++) {
                peList.add(new PeSimple(mips, new PeProvisionerSimple()));
            }

            ResourceProvisioner ramProvisioner = new ResourceProvisionerSimple();
            ResourceProvisioner bwProvisioner = new ResourceProvisionerSimple();
            VmScheduler vmScheduler = new VmSchedulerSpaceShared();

            Host host = new HostSimple(ram, bandwidth, storage, peList);
            host.setRamProvisioner(ramProvisioner).setBwProvisioner(bwProvisioner).setVmScheduler(vmScheduler);
            createVms(host, hostElement, bandwidth);
            hostList.add(host);
        }

        return hostList;
    }

    private void createVms(Host host, Element hostElement, long bandwidth) {
        NodeList vmNodeList = hostElement.getElementsByTagName("VM");
        for (int k = 0; k < vmNodeList.getLength(); k++) {
            Node vmNode = vmNodeList.item(k);
            Element vmElement = (Element) vmNode;
            // VM参数
            long vmNumOfCores = Long.parseLong(vmElement.getElementsByTagName("core").item(0).getTextContent());
            double vmMips = Double.parseDouble(vmElement.getElementsByTagName("mips").item(0).getTextContent());
            int vmRam = Integer.parseInt(vmElement.getElementsByTagName("ram").item(0).getTextContent());
            long vmStorage = Long.parseLong(vmElement.getElementsByTagName("storage").item(0).getTextContent());

            long vmBandwidth = bandwidth / vmNodeList.getLength();

            CloudletScheduler tasksScheduler=  "SPACE_SHARED".equals(SimulationParameters.CPU_ALLOCATION_POLICY) ? new CloudletSchedulerSpaceShared() : new CloudletSchedulerTimeShared();

            Vm vm = new VmSimple(vmList.size(), vmMips, vmNumOfCores);
            vm.setRam(vmRam).setBw(vmBandwidth).setSize(vmStorage).setCloudletScheduler(tasksScheduler);
            vm.setHost(host);
            vmList.add(vm);
        }
    }

    public List<DatacenterSimple> getDatacentersList() {
        return datacentersList;
    }

    public List<Vm> getVmList() {
        return vmList;
    }
}

测试

/**
 * @Author: mhh
 * @Date: 2021/8/9
 * @Description: 使用配置文件生成数据中心
 */
public class Test {

    // 创建云任务
    private static final int CLOUDLETS = 4;
    private static final int CLOUDLET_PES = 1;
    private static final int CLOUDLET_LENGTH = 10000;

    public static void main(String[] args) throws Exception {
        new Test();
    }

    private Test() throws Exception {
        // 1.设置日志级别
        // Log.setLevel(WARN);
        // 2.初始化CloudSim
        CloudSim simulation = new CloudSim();
        // 3.创建数据中心代理
        // 创建代理，该代理是代表云客户进行管理其VM和Cloudlet的软件
        // 与云用户直接交互，充当用户与数据中心的中间人，屏蔽了云数据中心的内部操作
        // （如虚拟机的创建、管理、任务单元在虚拟机上的分配），
        // 用户只需要提交自己的服务请求即可。
        DatacenterBroker broker0 = new DatacenterBrokerSimple(simulation);
        // 4.创建数据中心、创建主机列表
        DatacentersManager serversManager = new DatacentersManager(simulation);
        serversManager.createDataCenters("mobile/src/main/resources/datacenters.xml");
        List<DatacenterSimple> dataCenterList = serversManager.getDatacentersList();
        // 5.虚拟机列表
        List<Vm> vmList = serversManager.getVmList();
        // 6.创建云任务
        List<Cloudlet> cloudletList = createCloudlets();
        // 7.提交划分的虚拟机列表到代理
        broker0.submitVmList(vmList);
        // 8.提交云任务
        broker0.submitCloudletList(cloudletList);
        // 仿真开始
        simulation.start();
        // 获得仿真结果
        final List<Cloudlet> finishedCloudlets = broker0.getCloudletFinishedList();
        // 打印输出
        new CloudletsTableBuilder(finishedCloudlets).build();
    }

    /**
     * Creates a list of Cloudlets.
     */
    private List<Cloudlet> createCloudlets() {
        final List<Cloudlet> list = new ArrayList<>(CLOUDLETS);

        final UtilizationModelDynamic utilization = new UtilizationModelDynamic();
        final UtilizationModelFull utilizationModelFull = new UtilizationModelFull();

        for (int i = 0; i < CLOUDLETS; i++) {
            final Cloudlet cloudlet = new CloudletSimple(CLOUDLET_LENGTH, CLOUDLET_PES);
            cloudlet.setSizes(1024)
                    .setUtilizationModelBw(utilization)
                    .setUtilizationModelRam(utilization)
                    .setUtilizationModelCpu(utilizationModelFull);
            list.add(cloudlet);
        }
        return list;
    }
}

结果

                                         SIMULATION RESULTS

Cloudlet|Status |DC|Host|Host PEs |VM|VM PEs   |CloudletLen|CloudletPEs|StartTime|FinishTime|ExecTime
      ID|       |ID|  ID|CPU cores|ID|CPU cores|         MI|  CPU cores|  Seconds|   Seconds| Seconds
-----------------------------------------------------------------------------------------------------
       2|SUCCESS| 2|   0|        4| 2|        2|      10000|          1|        0|         2|       2
       0|SUCCESS| 2|   0|        4| 0|        1|      10000|          1|        0|        10|      10
       1|SUCCESS| 2|   0|        4| 1|        1|      10000|          1|        0|        10|      10
       3|SUCCESS| 2|   0|        4| 0|        1|      10000|          1|       10|        20|      10
-----------------------------------------------------------------------------------------------------