Load balancing users across datacenter using XenDesktop 7.6

We get requirement quite often to load balance users across datacenter and provide DR with XenDesktop. There are tons of article which will help you to design so. But what we are discussing here is load balancing users within delivery group.

Requirement : Load balance users delivery group across datacenter. If there are 100 users in a particular use case then 50 users should be directed to datacenter A and 50 users should be redirected to datacenter B.

Challenge: It would have been easy if we had to just load balance users. We could have used GSLB and distribute users in round robin fashion. But when it comes to delivery group this has its own challenge. To achieve this we do require single farm architecture. To build single farm architecture we do require SQL availability across the location. Challenge is with the amount of require bandwidth and latency within India. In general latency across two cities in India is around 60ms.

Gotchas: Profiles availability across datacenter. Microsoft does not support profile replication. So if we need profiles with the users then we must use two separate store at each datacenter.

How to achieve this: To start with I will put some drawing to make it simple.

Component configuration:

Two Delivery Controller at both datacenter: Total of four  Delivery Controller will be part of the single XenApp/XenDesktop Site. But here is the catch, VMS at respective DC will be pointing to respective Delivery Controller . So VMS will be register with only with respective site delivery controller.

Two StoreFront at both the datacenter: Two storefront will be in cluster at each of the datacenter. NetScaler will be used to load balance each of the storefront farm across datacenter.

Separate PVS farm at each of the datacenter: Each of the farm will be streaming VM’s in their respective datacenter.

Now coming to the important part is SQL setup. There are many ways we can setup SQL for database replication and I am not going to explain those. You can refer to article like this to get that configure. What I will explain you is how we did the setup in our environment. Two  SQL has been setup with Multi Subnet fail over cluster and something similar explained here

In our case we have one node at each of the site. WFC has been setup with the following roles

Under the server name there are two IP’s and this is used for Availability Group Listeners under SQL

WFC resource property is important to understand for failover .

 

This is how listener group looks like

We are replicating three database a)Site b)Logging c)Monitoring using AlwaysOn High Availability. During site creation we pointed it to listener database and allow Studio to create database. Once database were setup, It was then moved to Always ON group.

 

Then we separated all the database and moved separately. Now time for testing? No before we start testing we have to follow few more steps to ensure Delivery Controller is MultiSubnet aware and logins are replicated. To do so I followed Citrix blog and download the script listed here. Now its time for powershell magic. Open powershell from desktop studio and check if you have all the scripts. We need to run Change_XD_TO_MultiSubnetFailover.ps1

 

Once script executed then it will be upload

Post this when we run get-brokerDBConnection it will showing multisubnetfailover=true.

Now make sure logins for all the DDC is created on replica database .

DDC is ready for fail over testing. Now we need to create delivery group for  datacenter A and map catalog corresponding catalog. Separate delivery group for datacenter B  mapped to catalog for respective dc.

Now we need to publish desktop  to this both deliver group.

Add-BrokerApplication -Name "Publised App Name" -DesktopGroup "Delivery Group A"

Add-BrokerApplication -Name "Publised App Name" -DesktopGroup "Delivery Group B"

So what will be the end result: Users will hit GSLB which will deploy users in round robin fashion across datacenter. Users will  land on one the LB Store Front server and will get access to application. Users will be load balanced in round robin fashion but will land on same delivery group. Delivery group which doesn’t have priority (Fail over priority can be defined for delivery group) defined. Delivery group is going to distribute users across the VM . Incase of one of datacenter goes down SQL connection will failover to other site. This will have to wait till DNS update happen and listner group IP is changed to other site. Then we will be using connection leasing feature of XD 7.6 which is similar to LHC of XenApp 7.6 .

Drop a note incase you have question.

Prepopulating Citrix Receiver within ICA session.

We get the requirement quite   often that once users logged into virtual desktop application should launch via seamlessly. Here seamlessly have many meaning  and it varies from customer to customer. For example one customer would like the application to be present as a shortcut in the start menu and when users click the application it must do single sign on.  There are various way to achieve this. Once can import receiver ADM template using gpedit.msc

To prepopulate the receiver with the URL

To prepopulate url , one can do it via adm template or via Citrix HDX policy . To do it via adm template, import it into local policy and then perform following settings

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Once storefront url is selected value must be entered in following format “

SalesStore;https://sales.mycompany.com/Citix/Store/discovery;On;Store for Sales staff” and even one doesn’t want to wish to have it. So once this is done it will prepopulate the URL.

Once url is prepopulated, SSO has to be done. To do the so , we must choose “local user name and password” and then choose Enable pass-through authentication.

This will allow single sign on and allow users to launch application seamlessly.

Failed to add a Failover Cluster Node because “SQL Server Agent” account name empty

I came across interesting issue on two occasion when I tried adding second node to the SQL 2012 cluster node. After it detecting the second server detail, account name for “SQL Server Agent”  is blank. After we typed password this still fail with error message “There are validation error on this page”

We tried rebooting boxes but that didn’t help. Finally to fix this we need to create

1. SQL Server agent 2. Add the same agent as fail over cluster resources.

You can do this steps on any of the fail over cluster node. Use following PS editor to run the command

$ClusterName = "YourClusterName"
$FciClusterGroupName = "SQL Server (MSSQLSERVER)" # may need to modify to reflect your environment

Add-ClusterResourceType -Name "SQL Server Agent" -Dll "sqagtres.dll" 

Output of command will be like this

Once this is done,select role –>Add Resource –> More Resources –>

More Resources –> SQL Server Agent

Select “New SQL Server Agent” and --->properties –>Dependencies select resource as “SQL Server”

Now select properties tab and type  InstanceName = <Name of the SQL server Instance name> VirtualServerName =<Name of the SQLCluster>

Now the “New SQL Server agent”  will start

Make sure the registry on primary server is set to 1

After above steps when setup is run again , it was able to see SQL Server Agent users name.

Yeah I am also a SQL expert

Source here

Citrix Profile and folder redirection without Microsoft GPO

Sometimes you have a situation where profile and folder redirection can not be done via Windows GPMC. Citrix provide you an option to do so via HDX policy. Citrix have inbuild policy which can used to achieve this. This way we may not require help from AD team and can be managed at our own. I am not going to explain  what all we can apply as part of UPM because everything is available here , here and here.  Profile and redirected folder path must be different .

1. To get this first make sure path is define in this way for each of the folder redirection highlighted in red

Along with each of the folder redirection make sure that “Redirect settings for <folder name>” is selected to “Redirect to the following UNC path”.

2. Make sure policy is applied to the users group

3. For UPM alone path should be set to \\path to folder\#SAMaccountname#or %username% also make sure following should be defined

For rest of the settings and best practices please follow the above mention 3 link .

Gud luck for not using Microsoft GPO :)

Expand vDisk for PVS 7.1 on Hyper-V

There are many article which talks about vDisk expansion on different version of PVS but couldn’t find one for PVS 7.1 using windows 2012R2. Here I am sharing what I have done. Download vhdtool.exe from here. After downloading the tool follow this command as shown below

Now open disk management on any machine and attach the vhd

Once disk is attached it will showup as expanded volume . Select the disk and then choose extend volume.

Select the entire size and then next

Detach the hard disk post expansion