by Jake Walsh, CTA

Hello All! 🙂

Yesterday, a CUGC Webinar took place covering a new community project called PowerScale! (Click here for the recording.)

PowerScale is a community-driven replacement for Citrix SmartScale, which went end of life in July 2019. PowerScale was created by Leee Jeffries, in response to a number of clients he works with asking for similar features.

PowerScale provides the following scaling features for Virtual Machines in a XenDesktop Environment:

• Scaling by Virtual Machine Numbers
• Scaling by CPU/RAM
• Scaling on a scheduled basis – e.g. business hours
• Scaling by Load Index

PowerScale also provides a dashboard with historical data – allowing you to log and retain data for analysis:

• Dashboard view of PowerScale Statistics
• Machines On/Maintenance/Scaled
• Farm CPU/Memory/Load Index/Session Averages
• Historical Dashboard and Logging Retention
• Configurable retention period

So, how do I get PowerScale Up and Running?
Installation is super easy and takes only 3 steps: Download, Configure, Run. It should take no longer than around 30 minutes from download to PowerScale up and running. Before starting, ensure that you have the following prerequisites:

• A Citrix Environment and Citrix Studio!
• Citrix PowerShell SDK – included on machines with Studio installed
• WMI Access enabled
• A Service Account that has access to the Citrix Servers (my account is a Citrix Admin and a Local Admin of the Session Hosts)

Step 1 – Download:

1. Head over to the Project GitHub Page: https://github.com/leeej84/PowerScale
2. Create a C:\PowerScale Folder on the Server that will run the script
3. Download the Project and Extract the Zip Contents into the C:\PowerScale Folder:

Step 2 – Configure:

1. Edit the “Create Config File.ps1” script – and add the variables to suit your environment. (These are documented in the file)
2. For a super quick start to scale based on VM Number and Time of Day – only 9 variables are needed

• $citrixController = “ctx01.jake.lab”  – Our Citrix Delivery Controller the script will communicate with
• $machinePrefix = “CTXSESSION”    – The Machine name prefix for Session Hosts
• $businessStartTime =  “06:00” – The start time of the business working day
• $businessCloseTime = “18:00“ – The end time of the business working day
• $outOfHoursMachines = “1” – The number of machines to run outside of working hours
• $inHoursMachines = “3” – The number of machines to run inside of working hours
• $wmiServiceAccount = “DOMAIN\account” – The user account that the script will run as
• $wmiServicePassword = “PowerScaleRocks123“ – The password that the above account uses
• $testingOnly = $false  – we need to set this to True for power operations to take place – otherwise it will only log!
  

3. Finally – run the Create Config script and the variables and configuration will be securely stored ready for use:

Step 3 – running the Script

We are now ready to run the script – and this is done by running the “Decision Making.ps1” script, which will then run PowerScale using the configuration provided. This script can be set to run as a scheduled task. If you wish to have PowerScale running more regularly:

OK – so I am up and running, what next?

PowerScale also provides more detailed configuration options – for example:

• Dynamic Performance Scaling – based on load, not just machines on or off
• Session Closure – to force or not to force? This can be configured
• Isolating individual machines – in case you need to work on a specific machine
• Logging – all actions can be logged for further analysis and retention

Finally – PowerScale also has an awesome dashboard! This can be used to display the scaling and give an overview of the PowerScale activity:

• PowerScale creates a static HTML Dashboard with some JavaScript that displays graphs on recent activity.
• These are stored with the script inside a separate folder called “Dashboard”
• Retention of these Dashboard is configurable – <I32 N=”dashboardRetention”>3</I32> (3 days of Dashboards)
• The time when Dashboards will be recycled can also be configured – <S N=”dashboardBackupTime”>04:00</S> (This will now happen at 4am each day.)
• Important: Don’t forget to set your script run interval, this is used as a variance on the 04:00 backup window. This should match your scheduled task run time.

Hopefully this post will help you get up and running with PowerScale – as always, any questions, comments, feature requests are welcome – please reach out to either Leee or myself!

Until next time,
Jake Walsh