Tech Brief: Enhancing Azure Virtual Desktop
Azure Virtual Desktop (AVD) is a platform in Microsoft Azure to host and manage virtual machines. It is not just a set of operating systems that can be run in Azure but a set of services that can be used to deliver the virtual desktops to users. Staying true to Citrix’s track record, our solutions add unique value to this platform. The Citrix Virtual Apps and Desktops service allows our customers to deploy hybrid-cloud environments, making the most of their on-premises investments while embracing new cloud technologies like Azure Virtual Desktop in Azure
Let us first look at the AVD architecture:
It consists of the core level compute, networking, and storage that makes up the physical infrastructure that the Azure cloud runs on (managed by Microsoft). Then there are the virtual machines that run on the cloud hardware – Windows single session and multi-session desktops / server OS machines and remote apps. And the shared storage exposed to the machines like Azure Files and Azure AD and related services. The customer manages their Azure subscription. And finally, the services that run to manage and provide access to the desktops and applications.
For organizations to utilize the value add that Citrix provides, the bottom two layers of the AVD platform are retained. Citrix virtualization cloud services including Citrix Virtual Apps and Desktops (CVAD) service or Citrix Virtual Apps and Desktops Standard for Azure (CVAD Standard) service replace the top layer.
The on-premises data center resources are now included in the deployment and Remote PC Access enables connectivity to physical machines from the same environment / leveraging existing security. CVAD service unifies external access and identity management.
The Citrix value add is tabulated in the following table:
|1||Choice / Management||Hybrid Platform Management||Consume Azure Virtual Desktop as needed (burst capacity, migration to cloud, Disaster Recovery / Business Continuity, and more) while continuing to manage on-premises workloads from a single management plane. Remote PC Access is also managed and secured similarly from the same console. Support of Non-domain joined users.|
|2||Choice / Management||Provisioning||Automated GUI based provisioning with versioning and rollback support. Autoscale helps reduce compute cost in the cloud. Machine Creation Services including MCS I/O optimization and On Demand Provisioning, reduce premium disk costs. Zone preference helps with identifying on-prem or reserved instances to be used ahead of pay-as-you-go instances.|
|3||Choice / Management||Director / Monitoring and Citrix Analytics||A user centric monitoring system that helps pinpoint and resolve user/application issues (Shadows user session, send messages, disconnect / logoff sessions, logon duration drill-down) from one place. Also adding alerting (Session / app launch failures, resource consumption, and predictive analysis) and help desk integration with ITSM. Citrix Analytics enables advanced performance and security issue drill-down with automated real-time remediation.|
|4||Choice / Management||Delegated Administration and Configuration Logging||Granular control over administrative rights from help desk staff to IT owner coupled with full tracking of environment changes with date/time/admin action.|
|5||Experience||HDX||The Citrix HDX protocol represents over 30 years of experience connecting remote apps and desktops to endpoints over latent networks. Reduces data on the wire and enables several optimizations and endpoint peripherals. Citrix sessions connecting directly to the session host. Adaptive display technologies are customizable for individual apps. 3D Optimizations for CAD and manufacturing use cases.|
|6||Experience||Collaboration Platforms and Content redirection||Unified communications optimization extends beyond Teams for Windows and Linux to Skype for Business, Zoom, Jabber and so on. Browser Content redirection reduces data ingress and egress costs while offloading media rendering to the client, increasing server scalability.|
|7||Experience||Personalization, WEM, and Azure Files Integration||Extend FSLogix profile containers for multi-session access using Citrix Profile Management. Workspace Environment Management (WEM) helps control compute costs by automatically managing applications. Accelerates logon to AVD and increases single server scalability.|
|8||Experience||Citrix Gateway and SD-WAN||Citrix Gateway POPs improve performance by connecting through the nearest gateway POP. Citrix SD-WAN allows the AVD environment to connect back to the on-premises data / environment and enables break out of Internet based traffic and HDX content optimizations to reduce data ingress and egress costs and improving user experience.|
|9||Experience||Citrix Workspace||Citrix Workspace adds intelligent capabilities to organize, guide, and automate work in a single place, using microapps, universal search, relevant notifications and so on.|
|10||Security||Multi-factor authentication, Session Watermarking, Session Recording, and Smart card support||Compliance and regulatory requirements met. MFA extended to several IDPs natively and others via SAML. Smart card support. Endpoint Analysis scans and granular policy control over the content and the user can access.|
This tech brief showcases the value add provided under the 3 themes of Choice / Management, Experience, Security in Citrix products when setting up a workspace and using AVD based resources hosted in Azure.
Choice / Management
In this section, the features that enhance the admin’s ability to control, manage, and provision resources in the Azure Virtual Desktop environment are showcased.
Choice - Environment Management
Effective management of Azure Virtual Desktop resources is important to be able to reduce cost while ensuring the best possible user experience. The simpler it is to manage the environment; the quicker it is to remediate user issues; the easier the administrator’s job is. To that end Citrix provides several features:
- Hybrid Cloud Management from a single console
- Image management and brokering
- Cost optimization using active power management, Azure On-Demand provisioning, and MCS I/O optimization
Hybrid Cloud management
Any organization that is not creating their environment from scratch in the cloud, is going to have a transition period where existing resources reside in the on-premises data center, while new resources are brought up in the cloud. Additionally, some on-premises resources may never move to the cloud due to security / compliance / business / data affinity reasons. This is where CVAD service with the ability to seamlessly manage any deployment, whether it be the on-premises data center or the Azure based AVD resources. And management of your entire environment from the same CVAD console, makes the life of the administrator so much easier.
CVAD service also supports a multi-cloud deployment – allowing admins to manage their resources in other clouds as well. The ability to host resources in different clouds is often used for geographic, performance, or reliability benefits. The console is functional and very easy to use. Everything is within reach without overwhelming administrators or help desk staff with choices.
Even simpler - The CVAD Standard console, which uses CVAD service technology, is a DaaS offering to allow the admin to deploy Azure based workloads without being an Azure expert. It includes searchability for users and groups when assigning workloads.
Let’s dig right into it with the first step needed to be performed in the process of getting a cloud-based Desktop environment running.
Image management and brokering
A well tested imaging solution allows administrators to easily manage VMs throughout their lifecycle and rapidly scale their environment whether dedicated or non-persistent.
To get several virtual machines running in the cloud, a Golden Image must be created. The golden image creation can be done with either SCCM or App Layering or by simply downloading a template from Azure and making the necessary changes to the image, including installing the apps that must be delivered to all users.
While POC deployments are easy with even the most basic image management tools, administrators may face difficulties when there are groups of users that need different applications. This requirement results in the proliferation of the number of images that need to be managed with redundant apps within them. Updating the OS and the apps in each of these images would get cumbersome. Citrix App Layering can be used to make the process of updating this image and its contents much easier by splitting the image up into individual layers that can be stacked as needed.
Citrix App Layering also enables admins to make desktops available to different user groups (who require different apps) from the same set of layers. Consider the golden images of two pools in the following diagram.
Pool A for the Finance team requires Chrome and Accounting software while Pool B for the legal team requires Firefox and a PDF writer. Using a normal image management solution, the admin needs two different golden images and then must manage updates to the OS, the hypervisor driver, and Office 2016 in both the images, as and when an update occurs.
With App Layering the same layers for the OS, Hypervisor driver and Office 2016 and the required apps can be chosen, and the images created. The 3 layers are reused for both pools. This method also has no performance impact on the virtual machines and the admin can update any layer that has a change once and push the change to both pools.
Additional benefit of using App Layering is that the same image with the platform driver being swapped for a different hypervisor or cloud allows the admin to target a new platform for the same image.
Elastic layers give an admin the ability to push an application to a particular user during login by mounting a folder onto the machine that contains the application and redirecting the writes to the profile.
Expanding the scope of an Elastic layer to be able to hold all the writes (changes) the user is making during a session (which gets redirected to a share) is the functionality called user personalization layer. Learn more about this feature a little later when Profile Management is discussed.
Once ready with the image (prepared in any way the admin chooses to), the admin needs to be able to replicate it quickly and efficiently to make it available to the user.
Machine Creation Services (MCS)
Citrix MCS clones the golden image (using a snapshot). Using that clone in conjunction with an identity disk and a writeable delta disk has many benefits.
Taking a snapshot of the golden image allows an admin to easily test future changes and rollback a change if it is found to have an issue. The presence of a snapshot provides great flexibility to admins for issue remediation with a quick turnaround.
The use of a delta disk gives an admin the flexibility to use the image for non-persistent desktops as the delta disk can be discarded easily to revert the virtual machine back to its original state after the end of the session. This also helps with resetting desktops to keep the disk from increasing to a very large size.
With CVAD Standard, Citrix has made the creation of a catalog (using MCS) very simple.
Admins have options to choose the type of catalog, select the Azure subscription that the VMs are going to be created in. Next they choose the network connectivity back to the corporate network, the region the VMs are to be hosted in and whether an Azure Hub is to be used. For the machine, admins get to choose the storage type, the anticipated workload profile, and the number of machines. Then an admin selects the master image that is to be used to create the VMs and provides a name. Lastly the admin can set a power schedule, which will power on and power-off the VMs in the catalog using our Autoscale technology.
Going forward the day to day management of these machines is simplified with the CVAD service console, which not only gives admins a feature rich brokering console to manage the resources, but also apply granular policy controls.
Autoscale helps to reduce cost in the cloud by shutting down machines that are not needed during off peak times or when there is low load on the catalog. On the flip side Autoscale helps to power on the required machines before a shift or workday morning (logon storms) to handle the anticipated load so that user experience is not affected by long logon times when VMs boot as the users log in during these times. Admins can also define disconnection and logoff time outs to ensure idle machines can be shut down.
Another advantage is the ability to identify primary (lower cost resources, such as on-prem desktops or reserved instances) and secondary (pay-as-you-go instances) resources. Resources in the primary zone, are booted up first before trying to consume resources from the more expensive secondary zone. Secondary zone resources can be used for burst usage or during a business continuity or disaster recovery event. Hosts in the secondary zone would be turned off first as well when demand drops.
To learn more about Autoscale read the Autoscale Tech Brief
Azure On-Demand Provisioning
With Autoscale the machines can be shut down to reduce compute costs. But the machine still exists in Azure and therefore the organization would be charged for the all the static costs including storage costs. Another feature that is available in only the CVAD service is the Azure On-Demand Provisioning. This feature allows MCS to create the virtual machine only when a power on command is given and deletes the virtual machine when it is shut down. Resulting in no components of a machine being present when the machine is shut down, including the storage disks. Requires the use of Azure Managed disks.
MCS I/O optimization
Another line item in the organization’s Azure bill are I/O operations (IOPS), if using standard disks. The Windows operating system assuming that a physical disk is locally available, performs a lot of small random write operations. In a virtualized environment, this means increased load on the drives that host the OS. The increased load would lead customers to opt for the more expensive SSD options to host their VMs.
MCS I/O optimization – a RAM cache-based solution, is designed to offload random write operations to high-speed RAM. The redirection of I/O to cache reduces the number of writes to the disk and improves session responsiveness. As the RAM cache is consumed, MCS consolidates the writes and places large blocks of RAM cache onto disk. By creating larger, sequential blocks of data, MCS can provide better disk utilization allowing organizations to reduce costs by utilizing standard disks instead of high-performance disks.
Also, all reads are performed from the cache and only the data that is not in the cache is fetched from the disk. Reading from the cache also reduces the I/O operations that the organization is charged for in Azure.
Results from tests performed with the LoginVSI knowledge worker workload show, from the first an HDD with no cache, the user density comes out at 61. Adding MCSIO (fourth and fifth bar), with a small cache disk, user density increases to 76 or 77 users with the same workload.
Compare it to SSD disks, which are more expensive, and it is observed that the user density improved slightly from 74 to 77.
Consider a scenario where 1,000 users need desktops. These same 1,000 users, can be hosted on 12 D5_v2 instances instead of 13 without MCS I/O, with the VMs running on standard HDDs instead of Premium SSDs. Using Standard HDDs results in monthly cost savings (West US 2 pay-as-you-go monthly pricing as of writing this document) of approximately:
= Price of 1 VM running in Azure + Price of Premium SSD
= [Price of 1 D5_v2 VM + price of 1 Premium SSD managed disk
= USD [1366.56 + 9.29]
= ~USD 1375.85
Effectively saving of approximately USD 1,375 per month for every 1,000 users in the environment.
In addition to the cost savings, the user’s application response times are also improved, which directly impacts user experience scores.
Read more about the testing and results here
Choice - Monitoring and Analytics
The setup and design of an environment is just the first part of getting VDI infrastructure for an organization. For that reason, it gets the most focus from cloud providers. But the Day 2 and onwards of running and maintenance of a large environment in my opinion is as important. Hosting VMs in public clouds obfuscate the running of the machines, but the admin must still ensure that the user experience is consistent and high performing day in and day out.
Citrix gives full help desk visibility into user sessions, for both real-time debugging of specific user issues and performance, and broad visibility into the environment and trends.
As seen in the preceding screenshot, the admin has a view of what’s going on in the session, can shadow the session and can remediate from the same console.
The following is a list of some of the great features that Citrix brings to bear for the administrator and the help desk:
- Full featured integrated monitoring, alerting, and help desk support console
- Real time Session Details with drill-down for support actions
- Task Manager, process management, latency, user-perceived interaction latency, applied policy set, granular virtual channel status, client details, remoting protocol inspection, and so on.
- Always on monitoring of
- User Logons
- Connection Failures
- Server Resources
- Application Failures
- Breakdown of Logon Times
- Connection probing - synthetic app launch attempts to proactively test availability
- Predictive capabilities (for example capacity planning projection)
- Configuration Logging
- Allows for full tracking of environment changes with date/time/admin action
- Delegated Administration
- Granular controls over administrative rights from help desk staff to IT owner
- Citrix Director utilized to diagnose and resolve user/application issues
- Shadow Users
- Send messages to users
- Disconnect/restore desktop and application sessions
- Session Recording
- Citrix Director utilized to diagnose and resolve user/application issues
- Help desk integration
- ITSM Adapter for ServiceNow allows for API-level integration
- Advanced analytics for performance and security
- Enterprise-wide view of environment with ability to drill down to specific locations or individual users
- Monitor session responsiveness and latency
- Multi-product user behavior scoring to help admins evaluate security risks
In this section, the features that enhance the user experience when accessing their Azure Virtual Desktop resources are showcased.
Experience - HDX
For over three decades, Citrix has been in the business of remote delivery of desktops and applications. That experience led to various technologies designed to specifically come under the umbrella of HDX (High Definition eXperience). These technologies include the graphics remoting (the encoding, decoding, and rendering of the session window), the compression technologies for various data types, the transport protocol used to send the data. And our broad support for the peripherals, including support for printing, various keyboards, scanners, mice, audio and video peripherals, security / authentication devices and many more.
Some of the great features that must be highlighted are:
- Data transport technology optimizations
- Graphics optimizations
- Policies and Peripherals and peripheral connectivity
HDX is designed around three technical principles:
- Intelligent redirection
- Adaptive compression
- Data de-duplication
Applied in different combinations, they optimize the user experience, decrease bandwidth consumption, and increase user density per hosting server.
Intelligent redirection - Intelligent redirection examines screen activity, application commands, endpoint device, and network and server capabilities to instantly determine how and where to render an application or desktop activity. Rendering can occur on either the endpoint device or the hosting server.
Adaptive compression - Adaptive compression allows rich multimedia displays to be delivered even on constrained network connections. HDX first evaluates several variables, such as the type of input (text, video, voice, and multimedia), device, and display quality. It chooses the optimal compression codec and the best proportion of CPU and GPU usage. It then intelligently adapts based on each unique user and session characteristics basis. See the Tech Insight video.
Data De-Duplication - De-duplication of network traffic reduces the aggregate data sent between client and server. It does so by taking advantage of repeated patterns in commonly accessed data such as bitmap graphics, documents, print jobs, and streamed media. Caching these patterns allows only the changes to be transmitted across the network, eliminating duplicate traffic. HDX also supports multicasting of multimedia streams, where a single transmission from the source is viewed by multiple subscribers at one location, rather than a one-to-one connection for each user.
HDX Adaptive Throughput
HDX adaptive throughput intelligently fine-tunes the peak throughput of the ICA session by adjusting output buffers. The number of output buffers is initially set at a high value. This high value allows data to be transmitted to the client more quickly and efficiently, especially in high latency networks. Providing better interactivity, faster file transfers, smoother video playback, higher framerate, and resolution results in an enhanced user experience.
Session interactivity is constantly measured to determine whether any data streams within the ICA session are adversely affecting interactivity. If that occurs, the throughput is decreased to reduce the impact of the large data stream on the session and allow interactivity to recover.
For more info, see the Tech Insight video.
Read more about optimizing HDX bandwidth over high latency connections here.
HDX 3D Pro
Hardware encoding and optimization for CAD based use cases. Utilization of GPU enabled hosts in AVD can make the experience of 3D based use cases a lot better. These technologies with HDX policies such as Optimized for 3D graphics workloads, Build to Lossless, Progressive display and so on make image rendering and the user interaction with the session as near native as possible, even in challenging network conditions. The settings that are best suited for the majority of use cases are preconfigured. Admins use policies to fine-tune based on specific use groups that may have specialized needs. For example, the HDX 3D Pro policy is enabled for the set of users that require the graphics card for an application. Based on the sensitivity of the application the rest of the policies can be set to provide the desired experience.
Build to Lossless – when interacting with a model the quality may be reduced to increase interactivity but when the user stops interacting with the model a lossless image is rendered. The following side by side images showcases this feature.
Multi Monitor - Virtual Display Layout
The Virtual Display layout feature lets the user define a virtual monitor layout to split up a single 4K display into up to eight monitors. The user can create various monitor layouts and apps can be easily moved between monitors.
Windows display settings show the placement and scaling of each of the monitors. If the user wants to change the layout, they can define a new one by splitting the screen up by percentages of the client monitor resolution either horizontally or vertically. The user can set the DPI for each monitor individually.
In the current era, where new hires are being onboarded from home and organizations take longer to ship systems to their employees. The ability to work on multiple virtual screens, even though the user has just one physical one is a great productivity booster.
To learn more see the video here
Policies and Peripherals
The rich set of policies available to fine-tune the delivery of the app or desktop are extremely useful. The policies can be applied based on various criteria, such as group of users, a set of resources, a set of tagged objects and many more. The policies ensure the widest range of supported endpoints and devices while giving maximum control over the delivery of the session and what can and cannot be accessed by the user. Some examples are
- QoS for managing multiple connections on supported routers (see Multi-stream connections policy settings for details).
- Managing the image quality on the endpoint like settings for Visual Quality, Target frame rate and display memory limit (video buffer size in kilo bytes).
- Session reliability and Auto client reconnect settings that ensure smooth session reconnection when a network interruption may occur.
- Various inputs devices including but not limited to specialty keyboards, mice, recording equipment, identification devices, and so on.
- A plethora of clipboard settings, for example:
- Restriction on text and types of files that can be copied to the clipboard.
- No clipboard or one way redirection (client to server or vice versa)
Experience - Multimedia Delivery Optimization
Using HDX technologies and creating optimizations for the delivery of high-quality content and near native conferencing capabilities makes the entire remote desktop experience complete. When accessing content or using conferencing solutions from a cloud based resource several unique considerations are to be kept in mind. For users working from home, having large amounts of media data be routed to the customer data center or cloud location and then to the user’s endpoint (possibly on a latent connection) is extremely detrimental to the user experience. As much as possible, the admin would want to ensure that media content is directly delivered to the user (saving data ingress and egress cost in the cloud). Another major consideration is the need to offload processing of media from the cloud-based resources to the client endpoint. Media processing when offloaded to the client reduces the load on the cloud resources, resulting in savings on compute cost while bettering user experience and server scalability.
Citrix is at the forefront of development of these technologies, some of which are:
Browser content redirection (BCR)
With BCR the media encoding, and decoding is done on the client, which helps alleviate the load of rendering media heavy websites on the session host (running in Azure). Let’s look at how this feature makes AVD desktops more performant while increasing server scalability.
Browsing websites even casually, can use up a lot of CPU and Memory resources, as can be seen from this graph where 5 mins were spent browsing followed by a couple minutes of idle time.
Enabling Browser content redirection, offloads the media rendering from the CPU and reduces Memory requirements for the browser on each cloud hosted machine. This offload leads to higher single server scalability and reduces ingress and egress data costs as these large video files are not being sent up to the cloud.
The following were screenshots taken during our tests
Building on top of the Browser content redirection technology, Citrix in partnership with Microsoft (since the days of optimizing Skype for Business), gives admins a Microsoft Teams optimization solution. The ability to have the endpoint perform the encoding and decoding of the audio, video, and screen sharing bits of a call, increases the server scalability and call quality, by a significant margin. For users working from home on latent connections this means that audio and video call or screen sharing data is transmitted directly between them rather than being sent up to the cloud-based resources and then sent back to the recipient. This additional latency can mean the difference between a barely understandable video call and a perfectly smooth one.
Consider a scenario in a global company, where two users in different locations want to have a Teams call with each other and the desktops are hosted in a different location. The following map depicts such a situation with one user in the Netherlands and another in India.
The AVD resource location is US East and there was significant latency between these locations with the Azure region in the middle (920 ms round trip). The optimization reduces the latency by ensuring that in a 1:1 call, the users are connecting directly to each other rather than having to hair pin to the AVD server in the East US region hosting the call. This results in a sub 150 ms latency between the users (one way) in our example, that improves user experience immensely.
When Teams optimization is enabled, the improvement in the image in the call is evident.
And CPU consumption on the machines hosting the Teams call is also drastically reduced. Microsoft has released their own Teams optimizations solution, currently it only supports Windows 10 on the endpoints, Citrix’s value add is that, not only are Windows OS based clients supported, but also Linux endpoints.
Experience - Resource Optimization
Most important to the user is a short logon time and session responsiveness. See how with Citrix technologies admins can reduce resource consumption by managing the applications running inside a AVD desktop while reducing logon times and making apps and desktops more responsive. This is a win-win as there are cost savings to be achieved as well.
AVD desktop while reducing logon times and making apps and desktops more responsive. This is a win-win as there are cost savings to be achieved as well.
Some of the technologies of note are:
CPU and Memory optimizations
Workspace Environment Management (WEM) uses intelligent resource management and Profile Management technologies to deliver the best possible performance, desktop logon, and application response times for Citrix Virtual Apps and Desktops deployments.
Resource management - To provide the best experience for users, Workspace Environment Management monitors and analyzes user and application behavior in real time, then intelligently adjusts RAM, CPU, and I/O in the user workspace environment.
RAM optimization - When a new process is launched, it takes up more RAM than it needs for its normal running. But generally, processes will not relinquish these resources once they are allocated to them.
WEM in real time detects which processes are in the focus of the user. A portion of the RAM working set of apps that are not in focus can then be reclaimed. It is observed that even if these apps come back into focus, they generally need a smaller subset of the amount of RAM that was reclaimed from them. These actions optimize RAM consumption in the cloud and increase single server scalability.
The following graph shows the amount of memory consumed by a set of sessions, with and without WEM.
CPU Optimization - If a process is detected to be hogging CPU resources, it might negatively affect not only the session that it is running in, but also slow down other sessions running on the same machine and even impact logon times for other users.
CPU optimization with WEM, involves real-time monitoring of the process running on each VM. When a process is detected to be hogging CPU resources (for a defined amount of time), WEM automatically reduces the priority of the process. THis action allows other processes to use the CPU and alleviates server load. When the process is seen to have returned to low CPU consumption overtime, then its priority is reset back to normal.
Each Citrix Virtual Apps and Desktops release build is tested to validate the expected scale improvements, using LoginVSI. To validate the effect of CPU optimization by WEM, in a noisy neighbor scenario, these scale tests were extended. To simulate a noisy neighbor, a user not part of the LoginVSI knowledge worker test run, is added to the test setup. This user’s session is configured, to launch a process that consumes 3 CPU cores for an average of 50%-70% of total CPU, based on the number of cores in the Azure VM.
Windows 10 2004 multi-session VMs, were tested with Citrix Virtual Apps and Desktops 2006 installed and the Citrix Optimizer applied and WEM agent over HDX. To baseline the test results, the same test was run with Microsoft RDP as the connection protocol and the VMs had Out of the Box optimizations from Microsoft.
As can be seen from the following table, the inclusion of WEM, suppresses the effect of the CPU consuming noisy neighbor. The inclusion also increases the VSImax (no of users that can be supported on the machine) from 20% to 43%. Resulting in a higher number of users that can run on a single VM, even in this stress scenario.
Scale breakdown with Noisy Neighbor scenario:
|Azure Size||Baseline||Citrix HDX||% WEM Scalability Improvement|
As WEM reduces CPU spikes, another important inference from the results is, that the response time for the user is much better. Citrix Virtual Apps and Desktops sessions have an almost 1000 ms lower response time when compared to the baseline (at the instant VSImax is reached) for the same number of users.
Similarly, the latency observed in the session is between 25%-50% lesser on both the machines with 4 vCPUs. Both these results point to a much smoother and snappier user experience when WEM is in the picture.
Logon Time Optimization
To deliver the best possible logon performance, Workspace Environment Management replaces commonly used Windows Group Policy Object objects, logon scripts, and preferences with an agent which is deployed on each virtual machine or server. The agent is multi-threaded and applies changes to user environments only when required, ensuring users always have access to their desktop as fast as possible.
Find more information about WEM and its benefits here.
Experience - Personalization
In a non-persistent VDI environment, which includes AVD, users often require some level of personalization. Without persistent personalization, users are required to configure OS/app settings with every session.
Microsoft incorporates FSLogix containers into a AVD environment. This solution helps solve several personalization challenges. However, Citrix is able to extend the capabilities to include items like
- User-Installed Applications
- Multi-Session Support
- Azure Files Support
There are several scenarios where the admin would want to provide a desktop to power users and knowledge workers that want to be able to install apps on the desktops. These apps would not be persisted across session logouts with most solutions.
User personalization layer is a VHD based solution just like FSLogix Profile Containers but has the additional benefit of persisting user installed applications across session logouts.
The user personalization layer VHD is mounted on the VMs at logon over the network. The changes a user makes are redirected to the individual user’s user personalization layer, which resides in the shared storage location.
Note: It is not necessary for the entire OS image to be layered using App Layering to utilize this feature.
To learn more about the user personalization layer feature see the Tech Insight video.
Multi-session support for FSLogix containers
Another advanced use case, one which is more prevalent when users are remote, is when a user wants to have multiple, concurrent sessions.
With a VHD based profile solution, such as the FSLogix Profile Container or the user personalization layer alone, which requires the VHD to be mounted on the desktop that has the first session running on it, there is an inherent limitation. This approach allows only one session to write back changes. That is the first session that the user logs into has the VHD mounted in Read/Write mode, while the next session onwards the VHD can only be mounted as Read-Only.
So, when a user has a desktop session running and launches an app which writes to their profile, the changes made in the app are discarded.
For example, consider a physician working from home, they launch Outlook from their corporate Windows 10 device and a few minutes later launch’s the hospital’s EMR system on an iPad, to quickly check up on a few patients. That’s two simultaneous sessions, the first session that the physician logged into has the VHD mounted in Read/Write mode, while the EMR app session would have the VHD mounted as Read-Only. The changes made to the setting of the EMR app (default schemes, macros, favorites, and so on), are not written to the profile when they log off from it.
Citrix profile manager helps to synchronize files and settings that are changed in a Read-Only session. The centralized profile storage (user store) acts as the temporary storage for writes in the Read-Only sessions.
This allows each session to write changed files back and those changes are merge using the last writer win strategy at file level. Changes to registry hive files like NTUSER.DAT, are merged at registry key level. More information about this feature can be found at this link
Azure Files Integration
Citrix has built integrations to use Azure Files’ SMB based storage to host Citrix user personalization layer and Citrix Profile Management data. Azure Files support for on-premises Active Directory Domain Service Authentication (AD DS) enables these integrations. Azure Files shares can be mounted simultaneously in the cloud and on-premises, on Windows, Linux, or macOS. The benefit of having the personalization repositories in Azure, is that the data can be fetched quickly from the shares, making session launch and application data access much faster.
Azure Files alleviates the need to set up, manage, and update the SMB store infrastructure (physical or virtual windows machines). Azure Files can be used to move the data that is hosted in your data center to the cloud and then be accessed by machines in your hybrid environment.
Learn more about how to set up the same here.
Experience - App Delivery solutions
Citrix Gateway and Citrix Secure Workspace Access
Citrix Gateway is the preferred app delivery solution for reverse proxy to Citrix resources, providing VPN-less access to resources for end users.
Citrix Gateway Service has dozens of Points of Presence (POP) globally, connecting through the nearest Citrix Gateway POP improves performance. With CVAD service and Citrix Gateway service enterprises now may provide remote access to apps and desktops without additional VPN requirements along with following benefits:
- Multiple sites are implemented and maintained globally by Citrix
- Public IP addresses are implemented and maintained by Citrix
- Predictive DNS provides better user experience
- Certificates are implemented and maintained by Citrix
- Elastic scalability and High Availability are provided and managed by Citrix
- Enterprises pay as they grow and reduce operating expenses
- Faster onboarding for new customers
Furthermore, Citrix Secure Workspace Access combines the capabilities of instant secure access to SaaS and web applications through single sign-on (SSO), along with browser and cloud-based app controls, web-filtering policies and integrated user-behavior analytics to add an extra layer of security.
Endpoint Point Access scans and contextual access help to determine the level of security that a URL would need. Based on the result the system automatically determines whether the user can access the URL directly or the user must be redirected to a Secure Browser session where the URL is opened safely, or the URL needs to be blocked.
Citrix Analytics service using all these services as data sources provides comprehensive insights into user behavior. It uses machine learning algorithms to detect anomalous user behavior, troubleshoot user sessions and view operational metrics for users in an organization.
Citrix SD-WAN optimizes all the network connections needed by machines running in AVD. Working in concert with the HDX technologies, Citrix SD-WAN provides quality-of-service and connection reliability for ICA and out-of-band Citrix Virtual Apps and Desktops or Citrix Virtual Apps and Desktops Standard for Azure traffic. It also helps bridge the AVD deployment in Azure with the on-premises data center and other office locations.
Citrix SD-WAN supports the following network connections:
- Multi-stream ICA connection between users and their virtual desktops
- Internet access from the virtual desktop to websites, SaaS apps, and other cloud properties
- Access from the virtual desktop back to on-premises resources such as Active Directory, file servers, and database servers
- Real-time/interactive traffic carried over RTP from the media engine in the Workspace app to cloud-hosted Unified Communications services such as Microsoft Teams
- Client-side fetching of videos from sites like YouTube and Vimeo
Citrix SD-WAN provides optimized connectivity including:
- Deep HDX visibility - to prioritize delivery based on class of service
- VoIP packet duplication for reliability
- Security over the Internet
- Simple, integrated admin workflow
- Low latency and congestion avoidance
The breakout of internet traffic directly from the end point reduces the latency and ensure faster load times. Optimization of Unified Communications traffic including Microsoft Teams, make the conference audio and video the best-in-class. Citrix SD-WAN helps reduce the amount of data that needs to be sent to the AVD resources, consequently reducing the ingress and egress of data to your Azure subscription.
Integrations with Citrix Virtual Apps and Desktops Standard for Azure can provision the SD-WAN instances in the Azure Tenant, by the using the Citrix SD-WAN Orchestrator service.
Experience - Citrix Workspace
Citrix Workspace extends the capabilities that AVD sessions provide by encompassing them with a holistic workspace. It is not just the place to provide single sign-on access to apps and desktops. The Workspace helps the user by organizing their work, guiding them to the important tasks and automating the repetitive tasks to enable them to complete tasks without having to leave the workspace.
Citrix Workspace with Intelligence organizes work by funneling in notifications from various sources and then enables users to action on them by integrating actions and workflows into the Workspace by using microapps. Learn more about Workspace Microapps here.
Citrix Workspace adds universal search capabilities to all the data sources the workspace has been tied into including your on-premises SharePoint or SMB share, all the way to OneDrive in the cloud and everything in between. Increasing productivity by saving you time and the hassle of searching for that file you need right now but don’t know where it is stored.
Security provided by Microsoft is enhanced by adding additional layers with both client-side and server-side technologies. Features such as Session Watermarking, Session Recording, clipboard redirection policies and many more services from Citrix enhance the security stance. Extensions to authentication mechanisms with peripheral connectivity and the inclusion of various 3rd party identity providers, helps leverage existing investments, when extending the resource footprint in the cloud.
Delegated administration and configuration logging don’t just enhance change tracking and audit capabilities but also help remain compliant.
The following are some features of note to bolster the security of your AVD deployment:
Citrix extends the Azure multi-factor authentication capabilities with support for the following:
- MFA for CVAD service Administrators (TOTP)
- Citrix Gateway Service Active Directory + Token (Citrix SSO, MS Authenticator, Google Authenticator)
- Citrix Gateway Service with AAD MFA
- Citrix Gateway Service with Okta
- Citrix Gateway Service with Google IdP (in preview)
- Citrix Gateway Service with SAML IdP (Ping, ONeLogin, Auth0) (in preview)
- On-Premises Citrix Gateway and existing MFA configurations
- Smart Card / Proximity Card support
- Supported (Imprivata, Gemalto, and so on)
Read more about how the Citrix Workspace enables SSO with MFA in the tech brief.
For sessions that have a user accessing sensitive data, a great deterrent to having the data be stolen is a watermark. Especially if the watermark can uniquely identify the user. Citrix enables admins to configure what to display. This includes use logon name, client IP address, VDA IP address, VDA host name, login timestamp, and even customized text. Being a server-side feature it is applicable to all sessions (not just on specific endpoints) and is immune to process termination at the end point by the user as a workaround.
Citrix provides the ability to record all or part of a desktop or app session. The recording can be intelligently stopped when sensitive information is being displayed. The admin is also able to initiate recording of a session from the Manage tab in the CVAD service console to be able to help troubleshoot issues being experienced by users.
Session Recording provides flexible policies to trigger recordings of application and desktop sessions automatically. This enables regulatory compliance and an audit trail of what was done during a session. Playback can have events inserted in them to allow for easy seeking of the recording.
Security of the session recordings can be enhanced by encrypting them to ensure only authorized users can view them or digitally signing the recordings. The admin can even define the size of the recording file based on file size or duration. Citrix Analytics can automatically turn on Session Recording when a user’s risk score is above the configured threshold, helping admins discover and diagnose unusual behavior.
The value-add Citrix provides to Microsoft Azure Virtual Desktop is multifaceted and can help expand the capabilities of your Microsoft AVD based VDI environment into a full-fledged Workspace.
Citrix adds value in almost all the steps of the VDI deployment lifecycle in AVD, reducing cost and delivering the best possible user experience. Initial configuration and workload lifecycle tasks are streamlined through our provisioning tools and layering technologies. Day to day tasks are simplified through advanced monitoring, hands on help desk capabilities and performance and security analytics.
The following is a list of the features that were discussed in the detail in the preceding sections, grouped by theme:
- Choice / Management
- Hybrid platform management allows the admin to move the environment into the cloud as needed.
- Setup and VM consumption cost management – Citrix App Layering, MCS, MCS I/O optimization, Azure On-demand provisioning, and Autoscale.
- A full-fledged user centric help desk solution that can remediate issues in the same console. Delegated administration and configuration logging of actions taken in the environment.
- HDX technologies allow for the most optimized and customizable delivery of remote sessions with support for the richest set of peripherals.
- Performance, Single server scalability and compute consumption optimization – Workspace Environment Manager, Optimization for UCE solutions including Microsoft Teams, Browser Content Redirection, and SD-WAN based network optimization.
- Profile Management extension for multi-session scenarios, support for Azure Files.
- App Delivery solutions – Gateway enhances security with SSO and MFA, reduces latency to the resources and increase the resiliency of the environment, while enabling VPN-less access. SD-WAN provides QoS, reliability, out-of-band traffic for internet content, and optimizes connectivity between the cloud and on-premises data center. SD-WAN traffic optimization for UCE, Web, and SaaS apps delivers the best experience possible.
- Workspace – Enhances the user experience by integrating the AVD based resources into a Workspace that helps, organize, guide, and automate work for the user.
- Security – Session Watermarking, Session Recording, expanded multi-factor authentication capabilities, Security Analytics, Citrix Gateway service, and Citrix Secure Workspace Access service all add to layers of extra security to your environment.
Call to action:
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In this article
- Choice / Management
- Choice - Environment Management
- Choice - Monitoring and Analytics
- Experience - HDX
- Experience - Multimedia Delivery Optimization
- Experience - Resource Optimization
- Experience - Personalization
- Experience - App Delivery solutions
- Experience - Citrix Workspace