The document compares three hypervisors: XenServer, Hyper-V, and ESXi, covering aspects such as architecture, installation, and APIs. It includes personal setups for each hypervisor, networking configurations, and details about API interactions for XenServer and Hyper-V, including examples of code written to manage and monitor virtual machines. Additionally, it provides links to the full source code accessible on GitHub and personal website.

1. XenServer, Hyper-V, and ESXi - Architecture, API, and Coding
Agenda:
0. Quick hypervisor/market comparison
1. Architecture/Installation Comparison – XenServer, Hyper-V, and ESXi
2. API Comparison – XenServer, Hyper-V, and ESXi
3. Review code and demo programs I wrote - XenServer, Hyper-V, and ESXi
Humair Ahmed
hue@humairahmed.com
All code available on GitHub and Personal Website:
https://github.com/HumairAhmed
http://www.humairahmed.com/#Downloads
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2. XenServer, Hyper-V and ESXi - Architecture, API, and Coding
0. Quick hypervisor/market comparison
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3. XenServer, Hyper-V and ESXi - Architecture, API, and Coding
Gartner 2008 Analysis:
http://virtualization.info/en/news/2008/10/gartner-updates-market-share-reports.html
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4. XenServer, Hyper-V and ESXi - Architecture, API, and Coding
1. Architecture/Installation Comparison – XenServer, Hyper-V, and ESXi
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5. My Hyper-V Setup:
Windows Server 2008 R2
Full Installation of Windows
Server 2008 R2
Drivers
Enable the Hyper-V Role
In Server Manager
Hardware 2 nics on server connected to
switch on private local area network
Windows Server 2008 R2
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6. My Hyper-V Setup:
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7. My Hyper-V Setup:
You can access Hyper-V Manager separately or from
Server Manager:
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8. Is Hyper-V a True Type 1 Hypervisor?
Windows Server 2008 R2 Don 0 - Windows Server Virtual
2008 R2 Machine
Drivers Drivers
Install Hyper-V Hypervisor
Server reboots a few times
Hardware Hardware
Windows Server 2008 R2 Windows Server 2008 R2
with Hyper-V installed
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9. Is Hyper-V a True Type 1 Hypervisor?
The hypervisor is installed below the Windows Server 2008 R2
Installation. The parent partition (Windows Server) is now on Dom 0
and becomes the management platform for the hypervisor and the
hardware.
This is not the same as running as a process within the OS such as
Type 2 hypervisors like Fusion or VirtualBox.
There are actually three possible installation types for Hyper-V:
1. Server Core
2. Full Installation
3. Hyper-V server 2008 R2 (Free Version)
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10. My XenServer Setup:
Dom 0 - Linux Virtual
Machine
Embedded Linux on Dom 0
Drivers
2 nics on server connected to
switch on private local area network
Hypervisor
Hardware
XenServer
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11. My XenServer Setup:
-The software layer hypervisor boots
first. Runs in 64-bit mode.
-Next, the control domain boots, which is a 32-bit
Linux-based embedded distribution.
-The control domain is a normal XenServer VM
that has additional privileges granted to it which
allows it to control host hardware devices and
also create further guest domains.
-The XAPI management stack runs inside the
control domain and manages all resources
required for running guest domains.
It consists of a distributed database and control
software which listens on the administration
interface for XenAPI clients that issue
control instructions.
Graphic Source: Citrix XenServer Website 02/29/12 11

12. My XenServer Setup:
Accessing the XenServer Pool via XenCenter:
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13. My ESXi Setup:
Virtual Virtual
Machine Machine
Notice – no Dom 0 VM!!!!
2 nics on server connected to
Hypervisor switch on private local area network
Drivers
Hardware
ESXi
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14. My ESXi Setup:
Connecting to ESXi via vSphere Client:
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15. Compare Hyper-V to XenServer
Dom 0 - Linux Virtual Dom 0 - Windows Virtual
Machine Server 2008 R2 Machine
Drivers Drivers
Hypervisor Hypervisor
Hardware Hardware
XenServer Look familiar? Hyper-V
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16. Compare XenServer to ESXi
Virtual Virtual
Dom 0 - Windows Virtual Machine Machine
Server 2008 R2 Machine
Drivers
Hypervisor
Drivers
Hypervisor
Hardware Hardware
Windows Server 2008 R2 ESXi
with Hyper-V installed
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17. Compare Hyper-V to ESXi
Dom 0 - Linux Virtual Virtual Virtual
Machine Machine Machine
Drivers
Hypervisor
Hypervisor Drivers
Hardware Hardware
XenServer ESXi
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18. Compare Hyper-V to ESXi to XenServer
Our competition negatively portrays VMware ESX Server as a
“monolithic” hypervisor, but our experience and testing proves it to be the
best design. -- Vmware Website
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Graphic Source: VMware Website

19. XenServer Networking
By default, VM network packets are bridged (default) at the Ethernet layer over the
host NIC assigned to the virtual network interface in the VM. The bridge is similar
to an Ethernet switch, ensuring traffic from VMs are isolated from each other at Layer
2.
Traffic can be isolated by using VLANs, which will tag the Ethernet traffic separately but
still go over the same physical NIC on the host.
Graphic Source: Citrix XenServer Website 02/29/12 19

20. XenServer Networking
-The physical interface (usually eth0) on the physical host / Dom-0 is renamed to
"peth0". “peth0” becomes the "uplink" of the Xen server to the physical switch. “peth0”
is connected to the virtual bridge created by Xen.
-Virtual Network Interfaces (ex: vif0.0) are created in Dom-0 and act as network ports
for the bridges and are connected to the virtual network interfaces (eth0) of each virtual
machine.
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Graphic Source: http://cooker.techsnail.com/index.php/Virtualization-XEN

21. XenServer Networking
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22. Hyper-V Networking
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Graphic Source: http://blogs.technet.com/b/tnmag/archive/2009/01/15/automating-virtual-machine-host-deployment.aspx

23. Hyper-V Networking
-Similar to XenServer
-To create an external network in Hyper-V, a virtual network switch is created and
bound to the selected physical adapter.
- A new virtual network adapter is created in the parent partition which is then
connected to the virtual network switch. Virtual machines / child partitions can be
bound to the virtual network switch by using virtual network adapters.
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Graphic Source: http://social.technet.microsoft.com/wiki/contents/articles/151.hyper-v-virtual-networking-survival-guide.aspx

24. Hyper-V Networking
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25. ESXi Networking
-Physical adapters are uplinks in vSwitches
-Virtual adapters are connected to the vSwitches
-Each port on a vSwitch is assigned to a port group
-Each vNIC connects to a port within a port group on the vSwitch
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Graphic Source (Graphic 1): http://www.networkworld.com/community/node/24158

26. XenServer, Hyper-V and ESXi - Architecture, API, and Coding
2. API Comparison – XenServer, Hyper-V, and ESXi
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27. XenServer, Hyper-V, and ESXi API Architecture
Graphic Source: Citrix XenServer Website 02/29/12 27

28. XenServer API
-The XAPI stack is written in Objective Caml (or Ocaml - a high-level,
statically type-safe language).
Supposedly, this is to help prevent low-level memory corruption issues
such as buffer overflows or integer overflows which could be used in
malicious attacks over the administration network.
-The XAPI stack listens on port 80 (plain-text) and port 443
(SSL encrypted) for XenAPI requests.
-XenCenter uses the SSL port which ensure that traffic from the host is
Encrypted. XenAPI clients may or may not use SSL.
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29. XenServer API
-XenServer includes a XML-RPC based API.
XML-RPC is a web service approach used so PCs can call procedures on other
PCs. Extensible Markup Language (XML) provides a vocabulary for describing
Remote Procedure Calls (RPC), which are transmitted between computers using
the HyperText Transfer Protocol (HTTP).
-The XenServer API can be called from a remote system or locally from the
XenServer host.
-Remote calls are generally made securely over HTTPS, using port 443. RPC
involves libraries on both sides of the connection creating and processing
messages.
-There are five SDKs available, one for each of C, C#, Java, PowerShell,
and Python.
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30. XenServer API
XML-RPC Request Response Process
1. The client makes a procedure call using XML-RPC. The call specifies a method
name, parameters, and a target server.
2. The client packages the method name and parameters as XML and issues an
HTTP POST request containing the request information to the target server.
3. An HTTP server receives the POST request and passes the XML content to an
XML-RPC listener which parses the XML to get the method name and
parameters and then calls the appropriate method, passing it the parameters.
4. The method on the server returns a response to the XML-RPC process and the
XML-RPC process packages the response as XML.
5.The web server returns the XML as the response to the HTTP POST request.
6. The client parses the XML and extracts the return value which is then passed as
the return value back to the client program and the client program continues
processing with the return value.
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HTTP is used which means that XML-RPC requests must be both synchronous

31. Hyper-V API
-There are two methods you can use to interact with Hyper-V:
1.Using Hyper-V’s Windows Management Instrumentation.
Microsoft also provides a command line interface to WMI called Windows
Management Instrumentation Command-line (WMIC).
2. PowerShell Management Library for Hyper –V (Not officially supported by
Microsoft)
** Note there are other language bindings available
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32. Hyper-V API
-Windows Management Instrumentation is the standard API for Windows. It is built-in
into the core Windows OS. WMI allows scripting languages like VBScript or
Windows PowerShell to manage Windows PCs/servers
-PowerShell for Hyper-V is basically an extensive set of WMI interfaces:
Around 108 or more classed prefixed with Msvm_
-There is a PowerShell module for Hyper-V that you can install on the client
(http://pshyperv.codeplex.com/):
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33. Hyper-V API
Hyper-V WMI Classes:
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34. set-executionpolicy unrestricted
Hyper-V API
-To use the Powershell API you must have a Remote Desktop
Connection (RDC) with the Hyper-V machine.
-Install the PowerShell Module for Hyper-V
To run scripts on the system you must:
1. Either digitally sign the script
or
2. The easier method, but less secure, change your signing policy
- “set-executionpolicy unrestricted” in PowerShell
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35. vSphere API
The vSphere API is exposed as a Web service which runs on VMware vSphere
ESXi/vCenter. The API provides access to the vSphere management components.
The vSphere Web Services SDK provides interface/classes to interact with the
vSphere system.
H
O
SOAP/REST
S
VM T
Management VI API Hypervisor
D
Tool
Hardware
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36. vSphere API
-Used VI Java API for prior project with vSphere ESXi:
 VI Java API is a set of Java libraries that sits on top of existing vSphere
SDK Web Services interfaces. It provides a full managed object model
and run-time type checking, resulting in a dramatic productivity boost.
Application Application
VI Java APIs
Web Service Engine + VIM Stubs
Java Runtime (JRE)
----- HTTP/HTTPS
ESX / VirtualCenter Server
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37. VI API Object Model
Add problem statement
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38. XenServer, Hyper-V and ESXi - Architecture, API, and Coding
3. Review code and demo programs I wrote - XenServer, Hyper-V, and ESXi
02/29/12 38

39. Citrix XenServer Source Code
• Used Tkinter library to develop GUI for easily managing XenServers
• Also used the Pmw megawidgets library (which itself uses Tkinter as a base)
You will very quickly find there is little to no well written documentation on
the
Tkinter Python library. The Pmw megawidgets library has even less
documentation.
However, there is ONE book which may help some:
"All in all, I think it's well worth the price, considering it's the only Tkinter book out there."
--Jeff Blaine
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40. Citrix XenServer Source Code
• Used Python Binding to XML-RPC based API for managing, monitoring, and
performing operations on virtual machines.
You will very quickly find there that documentation for the Python binding is
extremely lacking. If my life depended on it, I would not have used Python.
The Java binding has a nice JavaDoc which is extremely helpful and was
even helpful developing in Python, although some classes were either not
implemented or named very differently .
• JavaDoc, XenServer Management API Guide, XenServer Software
Development Kit Guide, and experimenting are you best bet!
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41. Citrix XenServer Source Code
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42. Citrix XenServer Source Code
-Allows user to connect to a pool of XenServers via a GUI application
-In-case of emergency, user can logon to the slave host of the pool
-User can filter VMs in the pool by host
-User can perform some administrative functions like restart VM,
suspend VM, resume VM, etc.
-User can take snap shots of VM
*******************Advanced Monitoring Feature************************
User can set advanced network monitoring on multiple VMs at the
same time. If network monitoring detects a loss of network
connectivity for a VM, a snapshot of that VM is automatically
taken.
*****************************************************************************
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43. Citrix XenServer Source Code
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44. Citrix XenServer Source Code
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45. Citrix XenServer Source Code
*******************Advanced Monitoring Feature************************
User can set advanced network monitoring on multiple VMs at the
same time. If network monitoring detects a loss of network
connectivity for a VM, a snapshot of that VM is automatically
taken.
*****************************************************************************
-The goal was to create a monitoring station that would ping each VM every
few seconds. I decided to send two consecutive pings to each selected VM
around every 5 seconds. If any two consecutive pings are missed, the
management station should assume the VM has a network outage and
immediately take a snapshot of the VM.
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46. Citrix XenServer Source Code
*******************Advanced Monitoring Feature************************
User can set advanced network monitoring on multiple VMs at the
same time. If network monitoring detects a loss of network
connectivity for a VM, a snapshot of that VM is automatically
taken.
*****************************************************************************
-The following classes were created :
* VMNetMonitor – Every ManagedVM has a VMNetMonitor object
attribute
* Pinger – Every VMNetMonitor has a Pinger object attribute
* ping – Open source ICMP ping implementation that needs to be modified
to fit requirements. Every Pinger has a ping object attribute
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47. Citrix XenServer Source Code
-There is an open source Python-Ping implementation available - just
search “Python-Ping” on GitHub.
-The problem was - to monitor, multiple VM’s at the same time, I had to
make some changes not only so it would meet my requirements but also
to make it thread-safe so I could use multiple threads to monitor multiple
VMs at the same time!
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48. Citrix XenServer Source Code
* You must install XenServer Tools to be able to perform much of the
Operations on Guest VMs
What happens when you try to shutdown a guest that does not
have XenServer Tools installed?
Checkout Full Source Code at:
http://humairahmed.com/#Downloads
or
https://github.com/HumairAhmed
02/29/12 48

49. Hyper-V Source Code
WMI MSVM_ComputerSystem object:
Represents a physical computer system or virtual computer system (VM)
PowerShell Module Equivalent = Get-Vm:
Returns WMI objects representing Hyper-V Virtual Machines
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50. Hyper-V Source Code
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51. Hyper-V Source Code
Checkout Full Source Code at:
http://humairahmed.com/#Downloads
or
https://github.com/HumairAhmed
02/29/12 51

52. VMware ESXi Source Code
 Used the Java Swing library for the UI to programmatically and easily
manage ESXi via a GUI.
 Used VI Java SDK API to manage the server; create, delete, start,
stop, and monitor virtual machines; and import/export OVF.
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53. VMware ESXi Source Code
• There is a managed object type called ManagedObject in the VI
Java API and it captures all common properties and behaviors
of all managed objects.
• Two classes used extensively for this project are both
subclasses of the very important ManagedEntity class which is
the immediate super-class for all other types in the inventory
tree:
– HostSystem (Used for the Server level)
– VirtualMachine (Used for the VM level)
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54. VMware ESXi Source Code
• Additional important classes:
– ServiceInstance – first managed object seen in a typical application flow. Used to connect
and authenticate with the ESXi server
– ServerConnection – represents a connection to the server under a specific login user.
– InventoryNavigator – class used for helping to find managed entities inside the inventory
InventoryNavigator Example:
mes = new InventoryNavigator(rootFolder).searchManagedEntities("VirtualMachine");
mesHost = new InventoryNavigator(rootFolder).searchManagedEntities("HostSystem");
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55. VMware ESXi Source Code
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56. VMware ESXi Source Code
Checkout Full Source Code at:
http://humairahmed.com/#Downloads
or
https://github.com/HumairAhmed
02/29/12 56

57. Questions
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