https://next.nutanix.com/community-blog-154/new-x-play-actions-in-prism-central-2021-7-40005 The Prism Central Playbook Action is a tool that allows you to automate tasks based on triggers, such as events, alerts, or webhooks. You can define a series of actions (called a playbook) that perform operations on your infrastructure, such as adding or reducing resources on a VM2.
To use the Playbook Action for VMs, you need to meet some prerequisites, such as:
The Prism Central version must be 2020.11 or later.
The AOS version must be 5.15 LTSR or later.
The hypervisor must be AHV or ESXi.
The VMs must have Nutanix Guest Tools (NGT) installed and enabled3.
One of the possible reasons why the Playbook Action is no longer being triggered is that the virtual desktop CPU Usage alerts were not cleared. According to the Prism Central guide3, "If an alert has been triggered once and has not been cleared yet, then it will not trigger any action again until it has been cleared". Therefore, if the CPU Usage alert remains active for a virtual desktop, it will prevent the Playbook Action from adding more vCPUs to it.

gpumodeswitch is a command-line tool that is used to switch supported NVIDIA GPUs between compute and graphics mode. Compute mode allows multiple VMs to share a GPU for CUDA workloads. Graphics mode allows a single VM to use a GPU for graphics workloads12.

Citrix Workspace includes several components that can replace or integrate with the traditional Citrix infrastructure components, such as:
Citrix Cloud Services, which provide management and orchestration capabilities for Citrix Workspace, such as Citrix Virtual Apps and Desktops service, Citrix Gateway service, Citrix Endpoint Management service, etc.
Citrix Workspace app, which is a client software that enables users to access their apps and desktops from any device.
Citrix Cloud Connectors, which are software agents that establish a secure connection between Citrix Cloud Services and the on-premises or cloud-based resources, such as Active Directory, hypervisors, VDAs, etc.
According to Citrix documentation2, an administrator who chooses to move all of the backend Citrix infrastructure to be managed as a service by Citrix can use the following components:
Citrix Virtual Apps and Desktops service, which replaces the Citrix Delivery Controllers and provides centralized management and delivery of virtual apps and desktops.
Citrix Studio, which is still available as a web-based console for configuring and managing the virtual apps and desktops environment.
Citrix Gateway service, which replaces the Citrix NetScaler and provides secure remote access to virtual apps and desktops through a single URL.
Citrix StoreFront, which is still available as an optional component for providing users with self-service access to their apps and desktops through a web portal or native receiver.

non-persistent VDI desktops are virtual desktops that do not save any changes made by the user after they log off or shut down12. They rely on a master image that contains the OS, configuration settings, and other customizations that replicate to multiple virtual desktops1.

This is because this option will allow the administrator to use Citrix Director to reset user profiles on a Nutanix Files share that provides high performance, scalability, and resilience3.
Citrix Profile Management is a solution that allows administrators to manage user profiles and settings across different devices and sessions12. Nutanix Files is a software-defined file storage solution that provides high performance and scalability for file data12. Nutanix Files supports all forms of profile management with efficient metadata caching techniques that optimize for faster VDI logon times12. Nutanix Files offers two types of shares: standard shares and distributed shares3. Standard shares are hosted on a single file server, while distributed shares are hosted on multiple file servers for load balancing and high availability3.
https://portal.nutanix.com/page/documents/solutions/details?targetId=BP-2079-Citrix-Virtual-Apps-and-Desktops:BP-2079-Citrix-Virtual-Apps-and-Desktops