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Exporting a Snapshot of a Virtual Machine

  • Articolo

The following C# and VBScript samples demonstrate exporting a snapshot of a virtual machine (VM). Samples that demonstrate exporting a virtual machine can be found on the ExportVirtualSystemEx topic.

C#: The referenced utilities can be found in Common Utilities for the Virtualization Samples.

using System;
using System.IO;
using System.Management;

namespace HyperVSamples
{
    class ExportVirtualSystemExSnapshotsClass
    {

        static ManagementObject GetLastVirtualSystemSnapshot(ManagementObject vm)
        {
            ManagementObjectCollection settings = vm.GetRelated(
                "Msvm_VirtualSystemsettingData",
                "Msvm_PreviousSettingData",
                null,
                null,
                "SettingData",
                "ManagedElement",
                false,
                null);

            ManagementObject virtualSystemsetting = null;
            foreach (ManagementObject setting in settings)
            {
                Console.WriteLine(setting.Path.Path);
                Console.WriteLine(setting["ElementName"]);
                virtualSystemsetting = setting;
            }
            return virtualSystemsetting;
        }


        static string GetVirtualSystemExportSettingDataInstance(ManagementScope scope, ManagementObject snapshotSettingData)
        {
            ManagementPath settingPath = new ManagementPath("Msvm_VirtualSystemExportSettingData");

            ManagementClass exportSettingDataClass = new ManagementClass(scope, settingPath, null);
            ManagementObject exportSettingData = exportSettingDataClass.CreateInstance();

            exportSettingData["CopySnapshotConfiguration"] = 2;
            exportSettingData["CreateVmExportSubdirectory"] = true;
            exportSettingData["SnapshotVirtualSystem"] = snapshotSettingData.Path.Path;

            string settingData = exportSettingData.GetText(TextFormat.CimDtd20);

            exportSettingData.Dispose();
            exportSettingDataClass.Dispose();

            return settingData;
        }


        static void ExportVirtualSystemExSnapshots(string vmName, string exportDirectory)
        {
            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject virtualSystemService = Utility.GetServiceObject(scope, "Msvm_VirtualSystemManagementService");

            ManagementBaseObject inParams = virtualSystemService.GetMethodParameters("ExportVirtualSystemEx");

            ManagementObject vm = Utility.GetTargetComputer(vmName, scope);
            ManagementObject snapshotSettingData = GetLastVirtualSystemSnapshot(vm);

            if ( snapshotSettingData == null )
            {
                Console.WriteLine("There are not snapshots in the VM to be exported...");
                return;
            }

            inParams["ComputerSystem"] = vm.Path.Path;
            
            if (!Directory.Exists(exportDirectory))
            {
                Directory.CreateDirectory(exportDirectory);
            }
            inParams["ExportDirectory"] = exportDirectory;
            inParams["ExportSettingData"] = GetVirtualSystemExportSettingDataInstance(scope, snapshotSettingData);

            ManagementBaseObject outParams = virtualSystemService.InvokeMethod("ExportVirtualSystemEx", inParams, null);

            if ((UInt32)outParams["ReturnValue"] == ReturnCode.Started)
            {
                if (Utility.JobCompleted(outParams, scope))
                {
                    Console.WriteLine("VM '{0}' were exported successfully.", vm["ElementName"]);
                }
                else
                {
                    Console.WriteLine("Failed to export VM");
                }
            }
            else if ((UInt32)outParams["ReturnValue"] == ReturnCode.Completed)
            {
                Console.WriteLine("VM '{0}' were exported successfully.", vm["ElementName"]);
            }
            else
            {
                Console.WriteLine("Export virtual system failed with error:{0}", outParams["ReturnValue"]);
            }

            inParams.Dispose();
            outParams.Dispose();
            vm.Dispose();
            virtualSystemService.Dispose();
        }

        static void Main(string[] args)
        {
            if (args != null && args.Length != 2)
            {
                Console.WriteLine("Usage: ExportVirtualSystemExSnapshots vmName exportDirectory");
                return;
            }
            ExportVirtualSystemExSnapshots(args[0], args[1]);
        }
    }
}

VB 
option explicit 

dim objWMIService
dim managementService
dim fileSystem


const JobStarting = 3
const JobRunning = 4
const JobCompleted = 7
const wmiStarted = 4096
const wmiSuccessful = 0


Main()


'-----------------------------------------------------------------
' Main
'-----------------------------------------------------------------
Sub Main()


dim computer, objArgs, vmName, vm, exportDirectory

set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")
computer = "."
set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization")
set managementService = objWMIService.ExecQuery("select * from Msvm_VirtualSystemManagementService").ItemIndex(0)

set objArgs = WScript.Arguments
if WScript.Arguments.Count = 2 then
    vmName = objArgs.Unnamed.Item(0)
    exportDirectory = objArgs.Unnamed.Item(1)
else
    WScript.Echo "usage: cscript ExportVirtualSystemExSnapshots.vbs vmName exportDirectoryName"
    WScript.Quit(1)
end if

set vm = GetComputerSystem(vmName)

if ExportVirtualSystemExSnapshots(vm, exportDirectory) then
    WriteLog "Done"
    WScript.Quit(0)
else
    WriteLog "ExportVirtualSystemExSnapshots Failed."
    WScript.Quit(1)
end if



End Sub


'-----------------------------------------------------------------
' Retrieve Msvm_VirtualComputerSystem from base on its ElementName
'-----------------------------------------------------------------
Function GetComputerSystem(vmElementName)
On Error Resume Next
dim query
query = Format1("select * from Msvm_ComputerSystem where ElementName = '{0}'", vmElementName)
set GetComputerSystem = objWMIService.ExecQuery(query).ItemIndex(0)
if (Err.Number <> 0) then
WriteLog Format1("Err.Number: {0}", Err.Number)
WriteLog Format1("Err.Description:{0}",Err.Description)
WScript.Quit(1)
end if
End Function


'-----------------------------------------------------------------
' Get Last Snapshot of a Virtual System
'-----------------------------------------------------------------
Function GetLastVirtualSystemSnapshot(computerSystem, snapshot)


dim objVSSDs, vssd
dim query 

GetLastVirtualSystemSnapshot = false

query = Format1(&quot;ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_VirtualSystemsettingData&quot;, computerSystem.Path_.Path)
set objVSSDs = objWMIService.ExecQuery(query)

for each vssd in objVSSDs
if vssd.SettingType = 5 then &#39;SettingType = 5 means it is a snapshot
        GetLastVirtualSystemSnapshot = true
    set snapshot = vssd
end if
next



End Function


'-----------------------------------------------------------------
' Export a virtual system
'-----------------------------------------------------------------
Function ExportVirtualSystemExSnapshots(computerSystem, exportDirectory)


dim objInParam, objOutParams 
dim query
dim computer
dim exportSettingData
dim lastSnapshot
dim isSnapshotPresent

ExportVirtualSystemExSnapshots = false

if Not fileSystem.FolderExists(exportDirectory) then
    fileSystem.CreateFolder(exportDirectory)
end if

set objInParam = managementService.Methods_(&quot;ExportVirtualSystemEx&quot;).InParameters.SpawnInstance_()
objInParam.ComputerSystem = computerSystem.Path_.Path

query = Format1(&quot;ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_VirtualSystemExportSettingData&quot;, computerSystem.Path_.Path)
set exportSettingData = objWMIService.ExecQuery(query).ItemIndex(0)
exportSettingData.CopyVmStorage = true
exportSettingData.CopyVmRuntimeInformation = true
exportSettingData.CreateVmExportSubdirectory = true
exportSettingData.CopySnapshotConfiguration = 2
isSnapshotPresent = GetLastVirtualSystemSnapshot(computerSystem, lastSnapshot)
if isSnapshotPresent = false then
    WriteLog &quot;No snapshots were found on the VM when trying to export snapshot as VM.&quot;
    ExportVirtualSystemExSnapshots = false
Exit Function
end if

exportSettingData.SnapshotVirtualSystem = lastSnapshot.Path_.Path
objInParam.ExportSettingData = exportSettingData.GetText_(1)

objInParam.ExportDirectory = exportDirectory

set objOutParams = managementService.ExecMethod_(&quot;ExportVirtualSystemEx&quot;, objInParam)

if objOutParams.ReturnValue = wmiStarted then
    if (WMIJobCompleted(objOutParams)) then
        ExportVirtualSystemExSnapshots = true
    end if
elseif (objOutParams.ReturnValue = wmiSuccessful) then
    ExportVirtualSystemExSnapshots = true
else
    WriteLog Format1(&quot;ExportVirtualSystemExSnapshots failed with ReturnValue {0}&quot;, objOutParams.ReturnValue)
end if



End Function


'-----------------------------------------------------------------
' Handle wmi Job object
'-----------------------------------------------------------------
Function WMIJobCompleted(outParam)


dim WMIJob, jobState

set WMIJob = objWMIService.Get(outParam.Job)

WMIJobCompleted = true

jobState = WMIJob.JobState

while jobState = JobRunning or jobState = JobStarting
    WriteLog Format1(&quot;In progress... {0}% completed.&quot;,WMIJob.PercentComplete)
    WScript.Sleep(1000)
    set WMIJob = objWMIService.Get(outParam.Job)
    jobState = WMIJob.JobState
wend

if (jobState &lt;&gt; JobCompleted) then
    WriteLog Format1(&quot;ErrorCode:{0}&quot;, WMIJob.ErrorCode)
    WriteLog Format1(&quot;ErrorDescription:{0}&quot;, WMIJob.ErrorDescription)
    WMIJobCompleted = false
end if



End Function


'-----------------------------------------------------------------
' Create the console log files.
'-----------------------------------------------------------------
Sub WriteLog(line)
dim fileStream
set fileStream = fileSystem.OpenTextFile(".\ExportVirtualSystemEx-ExportSnapshot.log", 8, true)
WScript.Echo line
fileStream.WriteLine line
fileStream.Close


End Sub


'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format2(myString, arg0, arg1)
Format2 = Format1(myString, arg0)
Format2 = Replace(Format2, "{1}", arg1)
End Function


'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format1(myString, arg0)
Format1 = Replace(myString, "{0}", arg0)
End Function

Exporting the configuration of a Virtual Machine

ExportVirtualSystem

ExportVirtualSystemEx