Control Hyper-V VMs with Python

问题:

im trying to write a control VMs on a HyperV Server using Python. I start with connecting to the server the HyperV server runs on:

connection = wmi.connect_server(server="servername", namespace=r"root\virtualization", user=r"username", password=r"password") wmiServerConnection = wmi.WMI(wmi=connection) 

This gives me a wmi object for this connection.

For stopping and starting a VM I can simply use:

#get the wmi object representing the VM vmSystem = wmiServerConnection.Msvm_ComputerSystem(ElementName="VmName") #send change request to vm vmSystem[0].RequestStateChange(3) 

But before starting a VM I want to apply a certain snapshot. The class Msvm_VirtualSystemManagementService provides a method - ApplyVirtualSystemSnapshot/ApplyVirtualSystemSnapshotEx - for this. It needs the SnapshotSettingData as a parameter and I thought I could get that one using the GetSummaryInformation method of the same class. MSDN says this method returns a Msvm_SummaryInformation class.

I call this function like this:

#get the wmi class object vmManagement = wmiServerConnection.Msvm_VirtualSystemManagementService() snapshotInfo = vmManagement[0].GetSummaryInformation([1,107]) 

This should give me the name and the snapshot information for all VMs on the HyperV server. But all I get is list of COM Objects.

When I try to give a certain VM as parameter gotten from

vmSettings = wmiServerConnection.Msvm_VirtualSystemSettingData(ElementName="VmName") 

like this

snapshotInfo = vmManagement[0].GetSummaryInformation([1,107], [vmSettings[0]]) 

it crashes.

My questions:

1. Why don't I get a WMI object?

2. The second parameter is obviously wrong. MSDN says it needs CIM_VirtualSystemSettingData REF SettingData[] as parameter. Is the WMI object the wrong one? How do I get the correct parameter?

3. How can I retrieve the information I need from the COM object?

Or am I totally on the wrong track?

Thanks, Stefanie

回答1:

So, I finally found the solution. It was much easier than I thought, but whatever:

1.Connect to your server and get the WMI-object:

connection = wmi.connect_server(server=serverName, namespace=r"root\virtualization", user=username, password=password) wmiServerConnection = wmi.WMI(wmi=connection) 

2.Get the system object and the management service object:

#get object representing VM vmSystem = wmiServerConnection.Msvm_ComputerSystem(ElementName=VmName) #get object responsible for VM vmManagement = wmiServerConnection.Msvm_VirtualSystemManagementService() 

3.Get the objects associated with the VM:

#get objects the VM contains     vmObjects = vmSystem[0].associators(wmi_result_class="Msvm_VirtualSystemSettingData ") 

4.Apply the snapshot you want:

for singleVmObject in vmObjects:         if(singleVmObject.SettingType == 5 and singleVmObject.ElementName == snapshotName):         retVal = vmManagement[0].ApplyVirtualSystemSnapshotEx(vmSystem[0].path(), singleVmObject.path()) 

Further documentation can be found here:

http://timgolden.me.uk/python/wmi/wmi.html

http://msdn.microsoft.com/en-us/library/cc136986(v=vs.85).aspx

文章来源: Control Hyper-V VMs with Python