(CORE) CORE (2021)

LibVirt Net Core wrapper test on production QEMU/KVM server.

What is https://libvirt.org/? This is public library related to QEMU/KVM. This additional opportunity to control QEMU/KVM server, main opportunity is VIRSH command. Look to this page please - Microservice with report of QEMU-KVM server (VirtualMachines, Storage, Network). Also demo of Linq, Lambda, Inheritance model. - this is way to control QEMU/KVM server programmatically by own code.

libvirt library installed as separate Linux package:


# sudo apt install libvirt-daemon-system

This library allow create external connection from VM Manager to QEMU/KVM server.



Also this library used for SPICE/VNC VirtViewer.



Main future of this library is:



This library has .NET CORE wrapper https://github.com/IDNT/AppBasics-Virtualization-Libvirt and can be use in any .NET CORE API.

Below you can see my test of this library with real production QEMU-KVM server.


   1:  Imports System
   2:  Imports Libvirt
   3:  'https://github.com/IDNT/AppBasics-Virtualization-Libvirt
   4:  Module Program
   5:      Sub Main(args As String())
   6:   
   7:          Dim KvmHost As LibvirtConnection
   8:   
   9:          Console.Write("Get password string" & vbCrLf & ">")
  10:          Dim TmpPass = ReadPassword()
  11:          Console.WriteLine()
  12:          Dim LibVirtAU As LibvirtAuthentication = New OpenAuthPasswordAuth With {.Username = "root", .Password = DecryptString(My.Resources.Pass, TmpPass)}
  13:          Try
  14:              KvmHost = LibvirtConnection.Create.WithCredentials(LibVirtAU).Connect(My.Resources.Url, LibVirtAU)
  15:          Catch ex As Exception
  16:              Console.WriteLine(ex.Message)
  17:          End Try
  18:   
  19:          Console.WriteLine()
  20:          Console.WriteLine($"Connected to node {KvmHost.Node.Hostname}")
  21:          Console.WriteLine(Environment.NewLine + "[Node]")
  22:          Console.WriteLine($"   Total Memory ..........: {KvmHost.Node.MemoryKBytes / 1024 / 1024} GB")
  23:          Console.WriteLine($"   Free Memory ...........: {KvmHost.Node.MemFreeBytes / 1024 / 1024 / 1024} GB")
  24:          Console.WriteLine($"   CPU Model .............: {KvmHost.Node.CpuModelName}")
  25:          Console.WriteLine($"   CPU Frequency .........: {KvmHost.Node.CpuFrequencyMhz} MHz")
  26:          Console.WriteLine($"   CPU NUMA Nodes ........: {KvmHost.Node.CpuNumaNodes}")
  27:          Console.WriteLine($"   CPU Sockets per Node ..: {KvmHost.Node.CpuSocketsPerNode}")
  28:          Console.WriteLine($"   CPU Cores per Socket ..: {KvmHost.Node.CpuCoresPerSocket}")
  29:          Console.WriteLine($"   CPU Threads per Core ..: {KvmHost.Node.CpuThreadsPerCore}")
  30:   
  31:          Console.WriteLine("[VMS]")
  32:          For Each VM In KvmHost.Domains
  33:              'full VM.XmlDescription working!
  34:              Console.WriteLine($"   {VM.Name} ({VM.UniqueId}) {VM.State} osInfo={VM.OsInfoId} Up={TimeSpan.FromSeconds(VM.UptimeSeconds).ToString()}")
  35:              Console.WriteLine($"    memory={VM.MemoryMaxKbyte / 1024} MB")
  36:   
  37:              Dim FS1 = New IO.FileStream($"{VM.Name}.jpg", IO.FileMode.Create)
  38:              VM.GetScreenshot(FS1, System.Drawing.Imaging.ImageFormat.Jpeg)
  39:              FS1.Close()
  40:              IO.File.WriteAllText($"{VM.Name}.xml", VM.XmlDescription.OuterXml)
  41:   
  42:              Console.WriteLine("      [Nic]")
  43:              Try
  44:                  For Each Nic In VM.NetworkInterfaces
  45:                      Console.WriteLine($"         {Nic.Address.ToString()} bridge={Nic.Source.Network}, mac={Nic.MAC.Address}")
  46:                  Next
  47:              Catch ex As Exception
  48:                  Console.WriteLine(ex.Message)
  49:              End Try
  50:   
  51:              GoTo SkipError1
  52:              Console.WriteLine("      [Disks]")
  53:              'VM.DiskDevices dont working => InvalidOperationException: Instance validation error: 'block' is not a valid value for VirXmlDomainDiskType.
  54:              Try
  55:                  For Each dev In VM.DiskDevices.ToList
  56:                      Console.WriteLine($"         {dev.Address.ToString()} {dev.Device} (driver={dev.Driver}) target={dev.Target.ToString()} source={dev.Source?.GetPath()}")
  57:                      Console.WriteLine()
  58:                  Next
  59:              Catch ex As Exception
  60:                  Console.WriteLine(ex.Message)
  61:              End Try
  62:  SkipError1:
  63:          Next
  64:   
  65:          GoTo SkipError2
  66:          'dont working => Can't determine path of storage pool $dsk-c with driver disk.
  67:          Console.WriteLine()
  68:          Console.WriteLine("[KvmHost Pools]")
  69:          Try
  70:              For Each Pool In KvmHost.StoragePools.ToList
  71:                  Console.WriteLine($"   {Pool.Name} (state={Pool.State} driver={Pool.DriverType} path={Pool.GetPath()}) {Pool.CapacityInByte / 1024 / 1024 / 1024} GB ({Pool.ByteAvailable / 1024 / 1024 / 1024} GB free)")
  72:              Next
  73:          Catch ex As Exception
  74:              Console.WriteLine(ex.Message)
  75:          End Try
  76:  SkipError2:
  77:   
  78:          Console.WriteLine()
  79:          Console.WriteLine("[KvmHost Volumes]")
  80:          Try
  81:              For Each Volume In KvmHost.StorageVolumes
  82:                  Console.WriteLine($"      Volume {Volume.Name} (type={Volume.VolumeType}, path={Volume.Path}) {Volume.CapacityInByte / 1024 / 1024 / 1024} GB ({Volume.ByteAllocated / 1024 / 1024 / 1024} GB allocated)")
  83:              Next
  84:          Catch ex As Exception
  85:              Console.WriteLine(ex.Message)
  86:          End Try
  87:   
  88:          Console.WriteLine("press [ENTER] to exit CPU Utilization")
  89:          Dim VM1 = KvmHost.Domains.Where(Function(X) X.Name = "D82-site").FirstOrDefault
  90:          While Not Console.KeyAvailable
  91:              Console.WriteLine($"{VM1.Name}'s CPU Utilization = {VM1.CpuUtilization.LastSecond}%")
  92:              Threading.Thread.Sleep(1000)
  93:          End While
  94:   
  95:   
  96:          Console.WriteLine()
  97:          Console.WriteLine("Waiting for VM lifecycle events...")
  98:          AddHandler KvmHost.DomainEventReceived, AddressOf KvmHost_DomainEventReceived
  99:          Console.WriteLine()
 100:          Console.WriteLine("[ENTER] to exit")
 101:          Console.ReadLine()
 102:          KvmHost.Close()
 103:   
 104:      End Sub
 105:      Private Sub KvmHost_DomainEventReceived(ByVal sender As Object, ByVal e As VirDomainEventArgs)
 106:          Dim VM = CType(sender, LibvirtDomain)
 107:          Console.WriteLine($"EVENT: {e.UniqueId} {VM?.Name} {e.EventType}")
 108:      End Sub
 109:   
 110:  ...
 111:   
 112:   

Full code of this test I uploaded to Github https://github.com/Alex-1347/LibvirtNetCoreWrapper.



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