Load Balance A Citrix Web Interface

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To me if you don't configure all of your Citrix Web Interfaces (WI) to use a network load balance (NLB) setup you are asking for trouble as you have now created a single point of failure within your environment!

NLB is available in Windows Server 2008 standard and enterprise so you should now have no excuses to implement this in to your environment.

First thing First lets configure 2 Windows 2008 R2 server with NLB, in my test environment the two servers are XenApp.ctxlab.com (192.168.219.129) and XenApp2.ctxlab.com (192.168.219.131) and the NLB address will be XANLB.ctxlab.com (192.168.219.135).


1.  Install the Network Load Balancing feature on both servers that will be hosting both the WI.

2.  Once NLB is installed start the NLB manager and right click to create new cluster.

3.  Enter the first member in the NLB cluster and click Connect and the Next

4.  Check that the IP address is correct and put a tick in the retain suspended state (to help avoid a webserver kicking in after rebooting during controlled maintenance) and click next.

5.  Enter the clusters IP address and Subnet Mask and click on OK.

6.  Add in the FQDN of the cluster and change the Cluster mode to Multicast.

7.  Click on edit to the current port.

8.  Change the port range to 80-80 and the protocol to TCP

9.  Once the port is changed click on finish.

10.  You should now see the first member of the cluster added correctly and add the other member of the cluster.  I wont give a description of each point here as this is done in nearly the exact same way as above I'd add the screenshots to help if anyone gets stuck.

11.  Once you have added the second member to the cluster you should now see both members working correctly.

An error occurred while making the requested connection

Please check out www.kaztechsolutions.co.uk for more of my technical posts, alternately please call us on 01932 268289. 

Recently I had an issue where I was getting the following error when trying to launch a Virtual Desktop via a CAG.

Upon looking closer at the issue I noticed that the Web Interface config had not been setup right and the URL for the STA was actually missing the correct path (http://IPAddressOfDDC/scripts/ctxsta.dll) to the STA and once it was changes to the correct format the Virtual Desktops could launch successfully.

If you have the same issue check the event logs of the Web Interface and see if event ID's 30016 and 30205 are being logged.

Hope this helps someone out.

How to delete License's on XenDesktop

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Every now and then you'll find that you might need to delete a few licenses on your XenDesktop installation generally due to over usage, bit of a pain when a user gets this error as it displays an error about not enough licenses available.

First from where you have installed the license server run the following commands from C:\Program Files (x86)\Citrix\Licensing\LS

udadmin -list

This will display who is currently using a license and when it is due to expire.


siobhan.andrews XDT_ENT_UD 2013.0815
stephen.dunn XDT_ENT_UD 2013.0815
steve.jerome XDT_ENT_UD 2013.0731
suzanne.ballantine XDT_ENT_UD 2013.0815
sylvia.munn XDT_ENT_UD 2013.0815
teena.omara XDT_ENT_UD 2013.0815

Next find the user who you want to delete and then type the following command.

udadmin -f XDT_ENT_UD -user teena.omara -delete

you have now released a license


Examples
udadmin -list
Displays all the users and devices.

udadmin -list -a
Lists all features, versions, counts of licenses, and the users and devices for each feature.

udadmin -f XDT_ENT_UD -user u8.08 -delete
Releases one user from one feature.

udadmin -f XDT_ENT_UD -device dn01.88 -delete
Releases one device from one feature.

This operation cannot be performed because the specified virtual disk could not be found.

Please check out www.kaztechsolutions.co.uk for more of my technical posts, alternately please call us on 01932 268289. 

Just had a customer who got the following error when booting a VM

"This operation cannot be performed because the specified virtual disk could not be found."

Turns out that sometimes if you have an ISO mounted in the DVD drive this can sometimes cause the above error.

Hope this helps someone out.

Sluggish Windows 7/2008 - XenServer 6.1

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If you get any issues with sluggish Windows 7 VM’s on XenServer 6.1 ensure you have the following hotfixes applied to the XenHost and then upgrade the XenTools on all VM’s after the Hotfixes have been applied.

XS61E003

XS61E004

XS61E006

XS61E008

XS61E009

XS61E010

Also other possible MS issue could be related to the following - http://support.microsoft.com/kb/2617858

KMS with VDI

Please check out www.kaztechsolutions.co.uk for more of my technical posts, alternately please call us on 01932 268289. 

Anyone doing VDI at somepoint will have to deal with MS licensing and the joys of KMS!  Now if you haven't done it before and you start to read about it on the Technet and what not apparently its really easy to setup and all you need is 25 unique connections to the KMS host to start activating Windows 7 and 5 unique connections for office 2010.  RUBBISH - there's loads of little "gotcha's" that both MS and Citrix don't make you aware of.  

Hopefully this will help a few people out with the pain that is KMS...!

Setting up the KMS Host

NOTE: Always run a CMD in elevated mode.

• Designate a KMS host – has to be 2008 R2 or Windows 7. (You can use 2003... If you have too.)
• Get KMS host key from your MS volume licensing site. DO NOT USE THE KMS CLIENT KEY!
• Run a cscript slmgr.vbs /dlv and you'll see that the KMS Host is currently using a KMS Client key.
• Run cscript slmgr.vbs /ipk XXXXX-KMS-host-key-XXXXX.  This changes the licensing mode to be a KMS Host instead of a KMS Client.
• cscript slmgr.vbs /ato to activate your KMS Host against your MS volume licensing.
• After activating the KMS key, restart the Software Protection Service.
• Re-run a cscript slmgr.vbs /dlv to see the current KMS count is 0 and you'll also notice that the licensing has changes to a KMS Host.

Setting up a KMS Client

• On the golden image if you have changed the license key to a MAK change back to a KMS client key.  Windows automatically comes using a KMS client Key but if you need to change it back use the key from the KMS Client Key website.  DO NOT ENTER THE KMS HOST KEY IN TO A CLIENT!
• On the golden image type the following command to verify the DNS SRV Record: nslookup –type= srv_vlmcs._tcp
• Check that you can ping the KMS host.
• Attempt Windows 7 KMS Client activation using the following command: slmgr.vbs /ato
• The activation attempt will fail with an error that the activation count is insufficient, this is fine but check on the KMS Host that it has received the request by running a cscript slmgr.vbs /dlv on the designated KMKS Host and the count should be 1.
• Since KMS requires 25 unique activation requests to activate the clients spin up 25 desktops.
• VDI-in-a-Box ensure that the activation timer is enabled within the template and for XenDesktop PVS install ensure that the vDisk is set to KMS.

• Now a KMS client will automatically try to register against the KMS host using the DNS SRV record but you can speed this process up by using the VAMT 2.0 to force the activation.   Select 25 or more VM’s and choose to active via KMS.

• Run a cscript slmgr.vbs /dlv to see the current KMS count should be above 25, all other windows 7 VM’s will now rergister.

Setting up Office 2010

• For office make sure that the KMS host has the Microsoft Office 2010 KMS Host License Pack installed along with the KMS Host Office 2010 key from the your MS volume licensing site.
• On the golden image make sure that the Office 2010 installation have the KMS client key and like Windows 7 Office 2010 comes with a KMS Client key.
• From a CMD run a cscript ospp.vbs /dcmid from C:\Program Files (x86)\Microsoft Office\Office14 to see the CMID.
• Start a new CMD and run the following command to allow access to run the Office rearm correctly - icacls C:\ProgramData\Microsoft\OfficeSoftwareProtectionPlatform /grant "Network Service:(OI)(CI)(R,W,D)" /t.
• Start a CMD and run a OSPPREARM.EXE from C:\Program Files (x86)\Common Files\microsoft shared\OfficeSoftwareProtectionPlatform and this will clear the CMID.
• Rerun a cscript ospp.vbs /dcmid and you'll see the CMID is now cleared.
• Save and/or publish image so that it is now live, if you are using VDI-in-a-Box make sure you tick the "reset activation timer" in the template.
• Activate Office 2010 on 5 desktops by running a CMD from  %programfiles(x86)%\microsoft office\office14\cscript ospp.vbs /act (note: activation will fail for the first 5 desktops and you can also use VAMT 2.0 to do this.)
• Veryify that unique CMIDs are created for each desktop by running %programfiles(x86)%\microsoft office\office14\cscript ospp.vbs /dcmid
• On desktop number 6, KMS activation should work without errors.

I hope this help a few people out and if i get some time I'll put some screenshots of the commands being run just to give a little bit more help.

Troubleshooting Tips
if you have to re-enter a office KMS key as you are currently using a MAK use the following command from %programfiles%\Microsoft Office\Office14.

 cscript ospp.vbs /inpkey:

Thanks

Citrix Access Gateway - Recovery Mode

Please check out www.kaztechsolutions.co.uk for more of my technical posts, alternately please call us on 01932 268289. 

I had an issue this week where I'd setup a XenDesktop environment and everything was looking good and internal testing showed everything was working as it should be.  I moved on to the configuration of the CAG VPX and after configuring just the hostname, Licensing, STA, Access List, Logon Points and the Date and time the CAG would restart it self over and over again until it went in to Recovery Mode.

Upon troubleshooting I started to configure the CAG bit by bit and I found that once I configured the STA the CAG would then restart - very strange.

So I enabled logging on the DDC using the Log EnablerV3 and I could see that I was getting STA error's logged in the broker log, so i started to think that this must have been a dodgy install even though XD installer didn't highlight anything once it had finshed.

So I had a quick peek in the registry and i could see under the following key that the STA identifier wasn't created correctly.

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\DesktopServer

So I re-ran the Broker_Service_x64.msi from the XD iso and then refreshed the registry and I could now see that the STA identifier was now correctly configured in the registry.

Hope this helps someone out.

XenDesktop Virtual Channels

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This blog describes how to change the Virtual Channel Priorities in the VDA in XenDesktop 5 and above and it also has which 

Virtual channels are used within an ICA connection exchange specific types of information between a client and server application. A few of the Virtual Channels implemented by Citrix are sound, graphics, CDM, USB, and printing. Based on different user scenarios, Virtual Channels priorities may need to be changed to lessen interactions between different types of content. This article describes how to change priorities of Virtual Channels in XenDesktop 5.

Remote Session Screen Update (THINWIRE) - CTXTW  ,0
Seamless Windows Screen Update (THINWIRE) - CTXTWI ,0
Clipboard - CTXCLIP,1
Client Audio Mapping - CTXCAM ,1
License Management - CTXLIC ,1
Video Server (Dead – Remember VideoFrame ?) - CTXVFM ,1
Program Neighborhood - CTXPN  ,1
CTXSBR ,1
Windows Media Redirection - CTXMM  ,1
Flash - CTXFLSH,1
USB - CTXGUSB,1
Smart Cards - CTXSCRD,1
Still cant find this one - CTXCTL ,1
End User Experience Monitoring - CTXEUEM,1
Client COM Port Mapping - CTXCCM ,2
Client Drive Mapping - CTXCDM ,3
Client Management (Auto-Update) - CTXCM  ,3
Printer Mapping for Non-Spooling Clients - CTXLPT1,3
Printer Mapping for Non-Spooling Clients - CTXLPT2,3
Printer Mapping for Non-Spooling Clients - CTXCOM1,3
Printer Mapping for Non-Spooling Clients - CTXCOM2,3
Printer Mapping for Spooling Clients (nearly all) - CTXCPM ,3
OEMOEM2,3
OEMOEM ,3

If you want to implement these virtual channels on a VDA add the following regkey 

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\GroupPolicy\Defaults\

Then create a MULTI_SZ named “VirtualChannelPriority” with the following contents but change these to your requirements:

CTXTW  ,0
CTXTWI ,0
CTXCLIP,1
CTXCAM ,1
CTXLIC ,1
CTXVFM ,1
CTXPN  ,1
CTXSBR ,1
CTXMM  ,1
CTXFLSH,1
CTXGUSB,1
CTXSCRD,1
CTXCTL ,1
CTXEUEM,1
CTXCCM ,2
CTXCDM ,3
CTXCM  ,3
CTXLPT1,3
CTXLPT2,3
CTXCOM1,3
CTXCOM2,3
CTXCPM ,3
OEMOEM2,3
OEMOEM ,3

Windows 7 Optimization and GPO's Settings

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Hi Guys,

I’d get my ideas down and put them up for discussion but no doubt over time I'll expand on this but this gives you a good base to work from.

Some are from Citrix best practices but the rest are what I think should be changed.

http://support.citrix.com/servlet/KbServlet/download/25161-102-648285/XD%20-%20Windows%207%20Optimization%20Guide.pdf

Disable following services

This can be done on the VM itself or via GPO added the settings to the below section.

Background Intelligent Transfer Service

Desktop Windows Manager Session Manager

Function Discovery Resource Publication

HomeGroup listener

HomeGroup provider

Offline Files

Security Center

SuperFetch

System Restore

Windows Defender

Windows Media Player Sharing Service

Group Policies applied to Windows 7 VM - Computer

Error Reporting: Administrative Templates – Windows Components – Windows Error Reporting Disable Windows Error Reporting: Enabled

Windows Update: Administrative Templates – Windows Components – Windows Updates Configure Automatic Updates: Disabled

System Restore: Administrative templates – System – System Restore Turn off System Restore: Enabled

Group Policies applied to Windows 7 VM - Users

Screensaver :Administrative Templates – Control Panel – Personalization

Enable screen saver: Enabled

Prevent changing screen saver: Enabled

Password protect screen saver: Enabled

Screen saver timeout: Enabled – 600 seconds

Force specific screen saver: Enabled – scrnsave.scr

Force folder redirection: Enabled (Include AppData, Desktop, Documents, Downloads, Favourites and Pictures and Music depending on how strict we want to be.)

Ensure each folder redirection is setup like so.

Add following via registry preferences through a GPO

Force Offscreen Composition for Internet Explorer: [HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main] "Force Offscreen Composition"=dword:00000001

Reduce Menu Show Delay: [HKEY_CURRENT_USER\Control Panel\Desktop] "MenuShowDelay"="150"

Disable all Visual Effects:

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects] "VisualFXSetting"=dword:00000003

[HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics] "MinAnimate"="0"

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced] "ListviewAlphaSelect"=dword:00000000 "TaskbarAnimations"=dword:00000000 "ListviewWatermark"=dword:00000000

"ListviewShadow"=dword:00000000

[HKEY_CURRENT_USER\Control Panel\Desktop] "DragFullWindows"="0" "FontSmoothing"="0" "UserPreferencesMask"=binary:90,12,01,80 ,10,00,00,00

Citrix Profile Manager GPO – Version 4 and above

IMPORTANT: make sure the version of the ADM added to the GPO is exactly the same as the version of the installation that is in the image.

Profile Management – Enable Profile Management - Enabled

Profile Management – Processed groups: Enabled (add AD groups containing required users)

Profile Management – Process logons of local Administrators: Disabled

Profile Management – Path to Store: Enabled (specify path to store)

Profile Management – Active write back: Enabled

Profile Management – Profile Handling – Template profile: Enable (if we want to standardise user profiles)

Profile Management – Advanced settings – Process Internet cookies files on logoff: Enabled

Profile Management – Log Settings – Enable logging: Enabled

Profile Management – File System – Exclusion list – Directories

$Recycle.Bin

AppData\LocalLow

AppData\Local\Microsoft\Windows\Temporary Internet Files

AppData\Local\Microsoft\Windows\Burn

AppData\Local\Microsoft\Windows Live

AppData\Local\Microsoft\Windows Live Contacts

AppData\Local\Microsoft\Terminal Server Client

AppData\Local\Microsoft\Messenger

AppData\Local\Microsoft\OneNote

AppData\Local\Microsoft\Outlook

AppData\Local\Windows Live

AppData\Local\Temp

AppData\Local\Sun

AppData\Local\Google\Chrome\User Data\Default\Cache

AppData\Local\Google\Chrome\User Data\Default\Cached Theme Images

AppData\Roaming\Microsoft\Windows\Start Menu

AppData\Roaming\Sun\Java\Deployment\cache

AppData\Roaming\Sun\Java\Deployment\log

AppData\Roaming\Sun\Java\Deployment\tmp

Profile Management – File System – Synchronization – folders to mirror: Enabled (AppData\Roaming\Microsoft\Windows\Cookies)

Profile Management – Streamed user profile – Profile Streaming: Enabled

Changes applied directly to VM

Disable Large Send Offload :[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BNNS\Parameters] "EnableOffload"=dword:00000000

Disable TCP/IP Offload :[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]  "DisableTaskOffload"=dword:00000001

Increase Service Startup Timeout [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control] "ServicesPipeTimeout"=dword:0002bf20

Hide Hard Error Messages [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows] "ErrorMode"=dword:00000002

Disable CIFS Change Notifications :[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer] "NoRemoteRecursiveEvents"=dword:00000001

Disable Logon Screensaver :[HKEY_USERS\.DEFAULT\Control Panel\Desktop] "ScreenSaveActive"="0"

Modify C:\ProgramData\Microsoft\Windows\Start Menu to reflect a “tidy” start menu

Optimizer

If we are using a PVS in an environment ensure that the PVS optimizer is run at least once on image or at the end of each image update process just to be on the safe side.

One time changes

Disable Boot Animation: bcdedit /set bootux disabled

Remove unused Windows components : Windows Media Center, DVD Maker, Tablet Components

Page file : Minimum and maximum the same

Final actions to be performed at each image update process.

Disk Cleanup

Run defragmentation

Optimize Antivirus

Clear event logs

Run a windows updates (potential)

Rerun PVS optimizer if client is using a PVS

XenDesktop Planning

Please check out www.kaztechsolutions.co.uk for more of my technical posts, alternately please call us on 01932 268289. 

Where and how do you start with planning a XenDesktop deployment???  After looking around the web for a bit I came to a conclusion that there really isn't anything out there that lays out exactly what you need and in what order to do it.

So after thumbling around the edocs that Citrix have on XenDesktop, finding some really good knowledge base articles and basically going through the installation of XenDesktop a few times this is what I've come up with.  

By no means am I saying this is the correct way or order to do a deployment every single time but it will give you (and me...) a good starting point to work from, highlight a few options you should consider before you get started and basically just help you out.

VM Desktop (Golden Image)
It's important that you plan your "golden image" appropriately and decide on how you want to deploy your virtual desktops, are you going to use MCS or PVS?  Are you going install all apps on your image or use XenApp?  These are just some of the questions you need to ask yourself before you start, have a read of the Preparing a Master VM eDocs article.

• What OS is required?
• Ensure that the hard disk for the master VM is attached at device location 0.
• Ensure you set enough hard drive space as this cannot be changed at a later date. vCpu's and memory can be changed though.
• Install on the VM the appropriate integration tools for your hypervisor.
• If you plan to deliver desktops from pooled and dedicated machines, join the VM to the domain of which you want users' desktops to be members and ensure that the master VM is available on the host where you want to create the machines.
• Install the Virtual Desktop Agent from the XenDesktop installation media.
• Install any third-party tools require such as AV.
• Install and configure any third-party applications that you do not want to virtualize.  Remember Citrix recommends virtualizing applications and delivering them to users' desktops with XenApp.

Note: In the case of streamed machines, image a vDisk from your master target device before you join the master target device to a domain - have a read of the following doc. 

If you plan to deliver desktops from pooled and dedicated machines, Citrix recommends that you create a snapshot of your master VM and name the snapshot in a way that allows you to identify the master VM in the future. If you specify a VM rather than a snapshot when creating a pooled or dedicated machine catalog, Desktop Studio will create a snapshot for you but you will not be able to name it.

VDA
When installing the VDA ask yourself the following questions before you begin, a lot of this information I found dotted around and there was not a defined things to look out for a consider. 

• What VDA do you require? VDA for HDX 3D Pro or just the standard VDA?  Remember if you require 3D pro you need to obtain your Key file beforehand.
• Choose advanced Install unless you are setting up a POC without personal vDisks or HDX 3D Pro, in which case you can select Quick Deploy.
• Remember to launch the install through the autorun and not by double clicking on the standalone installer.
• If you are using Personal vDisks what drive letters are already currently in use?  if you require to change the drive letter follow this article.
• Do you want HA for the VDA?  This is not an alternative to other HA solutions.
• Have you meet all the VDA requirements?
• What discovery method are you going to use to communicate with the controller?  AD or registry based?

Planning your Database

XenDesktop 5 and upwards is now fully dependant on an SQL database, all information is stored on the database and controllers communicate only with the database and not with each other.  Things to be considered and planned for are.

• Windows authentication must be used when connecting to the database.
• SQL Express can be used but should only be when doing a POC.  Remember Express doesn't offer any kind clustering or mirroring.
• Check the database requirements.
• Citrix recommends that you use a HA solution for your database using either the hypervisior's HA feature, SQL mirroring or SQL clustering with mirroring being Citrix's preferred method. 

Note: If you want to mirror the XenDesktop database, ensure that the database uses the full recovery model and not the simple model. When Desktop Studio is used to create a database on an external SQL server, the database is configured to use the simple model by default; this means the transaction log cannot be backed up and the database cannot be mirrored. To ensure the database is configured to use the full recovery model, create the database manually and then use Desktop Studio to generate the necessary setup scripts to be run on the database.

Planning your Controller 

For desktops to be usable they must register with the correct controller or with any one of the controllers if there are more than one.  Here is a good read on Controller planning but things to consider are...

• How will your controller be discovered?  AD or registry based?
• Do you require SSL communication between controllers?
• Is your SQL server spec'ed enough to handle possible boot stroms?
• Is the site capacity too much for your controller to handle and will you possibly have to "Scale up" and add more resources to your controller and SQL or will you "Scale Out" and create a new site with its own controller and SQL.  Here is a very good article on scaling.

XenDesktop Install

To be totally honest the install of XenDesktop is dead straight forward, its knowing how you want it configured and setup to provide you or your client with the best experience. Things to consider before you start your install on Xendesktop are.

• How are you going to split the components?
• Do you already have an existing license server that you can use?
• What SQL server are you going to use?  More about this later.
• Is a firewall enabled on the controller?  if so are the necessary ports open?
• Have you installed the prerequisite? or will you let the install do it for you?

Configuring a XenDesktop site

Before you start to configure your XenDesktop environment it's a good idea to have a few of the following details already decided on before you begin as there is nothing worse than having to do something twice!!!

• Specify a site name.
• Licensing server name and port.  NOTE: you will not be prompted for a license server if you've installed the license server component on the controller.
• Specify the database to use.
• What hyperversior will you be using?  VMware, XenServer or Hyper-V?  If you are using vmware you may need to either purchase a CA certificate or amend the the proxy.xml on the vCenter.
• Cluster to use along with the Networking that the VM's will use on the hypervisor.
• Storage to be used along with the personal vDisk storage if required.

Also another thing to consider when thinking about sites is do you require site failover for DR? You have a couple of options here but from a very high overview you have a couple of options.

• Configuring the Web Interface RecoveryFarm setting with a list of alternate sites.
• Use a NetScaler to intelligently load balance and validate that Web Interface and XML services.
• Fault tolerance can be increased yet further by using the Global Server Load Balancing (GSLB) features of NetScaler.

Choosing the Machine Type

It does help to have the machine type that you require decided on before you start to create your catalog's.  What machine type you require will also decide what image delivery option you need to take - MCS or PVS.  See below for some brief information on MCS vs PVS.

Here is a VERY quick overview of what each desktop is and who it best suits, read the following article for more information.

Pooled - Desktops that are allocated to users on a per-session, first-come first-served basis. Pooled-random machines are assigned to users at each logon and returned to the pool when they log off.  Perfect for task workers who require standardized desktops, who share workstation and do not require to install applications.

Dedicated - Desktops that are assigned to individual users. Machines can be assigned manually or automatically assigned to the first user to connect to them. Whenever users request a desktop, they are always connected to the same machine, so you can allow users to personalize their desktops to suit their needs.

Existing - The existing machine type enables you to use XenDesktop to manage and deliver user desktops that you have already migrated to VMs in the data center.

Physical - The physical machine type enables you to use XenDesktop to manage user desktops hosted on dedicated workstations or blade PCs, this enables you to support small numbers of users who have particularly demanding performance requirements.

Streamed - The streamed machine type enables you to deliver desktops to VMs and blade PCs that have been configured to load the operating system over the network from Provisioning services. Target devices are managed in Provisioning services as a device collection and the desktops are delivered from a Provisioning services vDisk imaged from a master target device. Using Provisioning services to deliver desktops enables you to leverage the processing power of existing hardware, while realizing all the benefits of centralized desktop management.

Machine Catalog

Machine catalog is a collections of VM's or physical computers are managed as a single entity and can only contain one machine type.

Pooled or dedicated machine catalog

• A host with sufficient processors, memory, and storage to accommodate the number of machines you plan to create.
•  master VM from which to create the desktops. 
• An admin AD account or enough pre-created AD computer accounts to use.

Existing or physical machine catalog

• VMs or dedicated blade PCs hosting user desktops.
• Active Directory user and computer accounts to assign to the VMs or blade PCs.

Streamed machine catalog

• A Provisioning services deployment with a vDisk.
• Device collections configured to load the vDisk over the network.
• AD computer accounts managed by PVS for each target device in the device collections.

PVS or Machine Creation Service?

As we are talking about machine types and catalogs I thought it best that we now add a little bit about whether to go with a PVS or use MCS. Just a few points to note on this matter and also read this article which has some really good pointers in.
              

MCS Pro's 

• Simpler to manage than PVS.
• Ideal for smaller deployments.
• Uses technology within the hypervisor and doesn't require an additional server(s) .

MCS Con's

• In some tests, it was shown that MCS required 1.5x as many IOPS on the SAN as PVS.
• MCS can only use dynamic disks, which incurs the expansion penalty during boot storms and reboots.
• MCSs is limited in that it is meant for hosted VDI desktops only, pooled or dedicated.

PVS Pro's

• Reduced IOPS compared to MCS.
• Ideal for large deployments.
• Organizations looking to utilize a hosted shared desktop model, a streamed VHD model or a Hosted VDI model with blade PCs can use be provided by a PVS.

PVS Con's

• To some the additional steps required to manage a PVS prove to complicated.
• Requires additional server(s) to host the PVS.

Client\User Considerations

Without doubt you will have to consider what the needs, wants and experience that a client\user requires.  some pointers for things to consider

• How are you going to Delegate Administration Tasks?
• How are you going to manage printers?
• Do you require USB devices within XenDesktop?
• How are you going to configure the HDX policies?  do you have a baseline?
• What connection timers will suit your/their needs?
• Do you require Workspace Control to be enabled? 
• What applications are required for the client/user? Are they even supported in XenDesktop or even XenApp.

This blog will be an ever expanding post but if you feel you would like to add something please don't hesitate to post your thoughts and i'll add them.

Hope this helps.

Error: Unable to contact the Hypervisor

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I came across this error recently when doing a POC for XenDesktop on Vmware ESXi 5.

Error: Unable to contact the hypervisor. Check that the address, user name, and password are correct; the Controller and hypervisor are connected; and the SSL certificates have been set up correctly if you are using HTTPS.

To get around this issue I had to change the Proxy.xml file located on the Virtual Center to accept HTTP communication which is located in the following directory

C:\ProgramData\VMware\VMware VirtualCenter\proxy.xml

Find the following sections of the XML file and change them from "httpWithRedirect" to "httpAndHttps"

Now from the knowledge base article its a tad confusing which part of the xml file you need to change, ignore the id= part and just look for "/" and change the access mode and also look for "/sdk"and change the access mode.

http://support.citrix.com/article/CTX125578