Start VM on Connect

Start VM on Connect is a feature that enables host pool VMs to automatically start when a user attempts to connect.

This is a major cost-saving feature. It allows you to set up an Auto-scaling configuration where the host pool size can be reduced to zero hosts (all session hosts are powered off) when not in use. For details, see Auto-scale History for Host Pools.

Supported clients

Start VM on Connect is supported when users connect from the Windows App and Web Client as well as the following clients:

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Configure Start VM on Connect

Enable Start VM on Connect to automatically power on session host virtual machines when users initiate a connection.

To configure Start VM on Connect:

1. At the account level, locate the host pool you wish to work with.

2. From the action menu, select Properties > AVD.

3. Select the Start on connect option.

   Note: The Start VM on Connect feature is generally used in conjunction with dynamic host pools where the minimum active host pool capacity is set to zero. A reminder is displayed to ensure that you have enabled the Start VM on Connect property for the host pool.

4. Set Min active host capacity to 0 (zero).

   

5. Select Save or Save & close.

Considerations

While the Start VM on Connect feature offers significant cost-saving benefits, it introduces certain limitations that you should be aware of.

Specifically, review the considerations below.

Scripted actions are not triggered

• Problem: Because this feature operates independently of Nerdio Manager’s automation framework, any scripted actions configured to run on VM startup will not be triggered. This happens because Nerdio Manager is not notified when a VM is started via Start VM on Connect, making the process functionally equivalent to manually starting the VM through the Azure portal.

• Troubleshooting: To address this limitation, you can implement scheduled tasks directly on the host pool VMs. These tasks should be configured to execute on the VM startup, thus replicating the intended automation. It is recommended to include these configurations in the base image to ensure persistence across re-imaging cycles.

Start VM on Connect does not modify the OS disk type of a VM

• Problem: In environments where Auto-scaling is configured to downgrade the OS disk type (e.g., to Standard HDD) during scale-in operations, the VM retains this disk type when started via Start VM on Connect. This may impact performance if not proactively managed.

• Mitigation: Consider one of the following methods:

  • Retain the OS disk type: You can choose not to alter the OS disk type during scale-in operations, thus ensuring consistent performance when the VM is started.

    

  • Enable pre-staging in your Auto-scale configuration:

    • By configuring pre-staging, Nerdio Manager proactively starts hosts and applies the designated OS disk type for running workloads. This ensures that VMs are optimized prior to user connection.

      

    • When implementing pre-staging, it’s important to configure appropriate session time limits within the host pool properties. This prevents scenarios where a VM started with a downgraded disk type remains active into peak usage periods, for example Monday mornings following weekend access.