Understanding how to correctly structure the Azure Virtual Desktop (AVD) environment can impact the performance, security, and usability of your virtualized workspaces. Let’s dissect every piece of the host pools architecture to grasp this topic better.
Host Pools in Azure Virtual Desktop Environment
Host pools are a group of virtual machines that registered to Azure Virtual Desktop as session host. These host pools can be of two types, Personal or Pooled, based on the work assignment to the users.
- Personal host pools: In this type, each user is assigned a dedicated virtual machine. It’s helpful for users who need a dedicated workspace with greater computing power than a typical user. The user-VM relationship is 1:1.
- Pooled host pools: In contrast, these host pools have multiple users share resources of a single virtual machine. This type has more flexibility but less computing power per user. The user-VM relationship is many:1.
Designing Azure Virtual Desktop Host Pools
Now that we have understood the basic construct of host pools, let’s talk about designing these. When designing your host pools, you need to consider the types of users and their computing power requirements. Personal host pools can be expensive but provide high performance. Meanwhile, pooled host pools are cost-effective but offer less performance per user.
Here you’ll have to analyze your user types and their specific requirements. Document the user requirements and start designing the host pool architecture accordingly.
Example Scenario:
Consider an organization ‘X’ with 100 users. About 75 users only require office suite and email services. While, the remaining 25 users are developers who require more resources for their development environment. Here, for office users 1-2vCPU and 4GB RAM might suffice while developers might need 4vCPU and 16GB RAM minimum.
This organization can save costs by designating one or more pooled host pools for office users and personal host pools for developers.
For pooled host pools, you have another critical decision to make – setting the maximum number of sessions per host or let Azure manage. If you opt for Azure management, it will use its algorithm to calculate based on your specified density, but the count might go a bit higher during peak use times.
Load Balancing of Host Pools
Azure Virtual Desktop offers two types of load-balancing for Pooled host pools; Depth-first and Breadth-first.
- Depth-first: This type fills one session host to its maximum capacity before directing users to the next session host in the pool.
- Breadth-first: This type distributes users evenly across all the available session hosts.
Depth-first load balancing optimizes cost as it ensures that any unused session hosts remain in the ‘Stopped’ state until necessary. Meanwhile, Breadth-first helps to assure that sessions are evenly distributed, which can improve the user experience in cases where session host performance varies.
As you can see, planning your host pools architecture requires detailed analysis and decision-making. Take your time to understand your users’ requirements, evaluate your options, and select the right types and configurations for your host pools. An appropriately planned host pools architecture can significantly improve the efficiency, cost-effectiveness, and user experience of your Azure Virtual Desktop environment.
In the next article, we will dive into the Auto-scaling feature for Host Pools which allows you to dynamically manage resources based on usage.
Practice Test
Host pools in Windows Virtual Desktop become a collection of one or more session hosts where users can access their resources.
- A. True
- B. False
Answer: A. True
Explanation: Host pools act as a collective resource of computing power in Windows Virtual Desktop, enabling users to access their resources.
For load balancing, Azure Active Directory uses Breadth-first method.
- A. True
- B. False
Answer: B. False
Explanation: For load balancing, Azure Virtual Desktop uses two methods – Breadth-first and Depth-first, not Azure Active Directory.
Which of the following statement is correct about assignment type in Host pools?
- A. ‘Pooled’ assign a user to multiple session hosts in the host pool.
- B. ‘Personal’ assign a user to one and only one session host in the host pool.
- C. Both A and B.
Answer: C. Both A and B.
Explanation: In Host pools, ‘Pooled’ means that a user assignment type can allow a user to log into the first available VM while ‘Personal’ means that a user assignment type guarantees a one-to-one relationship between the user and the VM.
Host pools can’t contain both RemoteApp applications and desktops in a single host pool.
- A. True
- B. False
Answer: A. True
Explanation: With Windows Virtual Desktop, you’re not able to include both desktops and RemoteApp applications in the same host pool.
Breadth-first is the default load-balancing method for new host pools.
- A. True
- B. False
Answer: A. True
Explanation: Breadth-first is the default load-balancing method for new host pools given that it helps maximize the utilization of Azure resources.
It is important to plan the host pool update method in Azure Virtual Desktop infrastructure articulation.
- A. True
- B. False
Answer: A. True
Explanation: Planning how you update session hosts in host pools is an integral part of Azure Virtual Desktop infrastructure planning.
Which statement is not true about Depth-first load balancing method?
- A. It fills up one session host before moving on to the next.
- B. It leads to cost savings.
- C. It distributes the sessions evenly across all session hosts.
Answer: C. It distributes the sessions evenly across all session hosts.
Explanation: Depth-first filling does not distribute the sessions evenly across all session hosts. Instead, it fills up one session before moving on to the next.
Host pools in Windows Virtual Desktop are region-specific.
- A. True
- B. False
Answer: B. False
Explanation: Host pools in Windows Virtual Desktop are globally dispersed and are not restricted to a specific region.
You cannot mix different virtual machine sizes in a single host pool.
- A. True
- B. False
Answer: B. False
Explanation: In a Windows Virtual Desktop host pool, you’re allowed to have different virtual machine sizes.
In Windows Virtual Desktop deployments, it is recommended to create one host pool and apply different user group rules.
- A. True
- B. False
Answer: B. False
Explanation: In Windows Virtual Desktop deployments, it’s recommended to segregate responsibilities and applications by creating separate host pools for specific user groups and their needs.
Interview Questions
What is a host pool in Microsoft Azure?
A host pool is a collection of Virtual Machines (VMs) in Azure Virtual Desktop that a user or group of users can connect to. You can customize the host pool’s settings according to your organization needs.
How can host pools in Azure Virtual Desktop be categorized?
Host pools in Azure Virtual Desktop can be categorized into two types – Personal and Pooled. Personal allows one user per VM while Pooled can accommodate multiple users on a single VM.
What is the significance of using a Load Balancing algorithm in host pools?
The Load Balancing algorithm in host pools allows for the distribution of user sessions across all available VMs in the host pool. This ensures that user load is balanced evenly across all VMs, and enhances resource utilization and efficiency.
What are the two types of Load Balancing algorithms available in Azure Virtual Desktop?
There are two types of Load Balancing algorithms available in Azure Virtual Desktop – Breadth-first and Depth-first. Breadth-first spreads user connections across all available session hosts in the host pool while Depth-first fills up one session host before distributing users to the next one.
How does the Maximum session limit work in Azure Virtual Desktop?
The Maximum session limit defines the number of users that a single session host in a host pool can accommodate at once. When the maximum limit is reached, Azure Virtual Desktop stops new connections till a session slot becomes free.
What is a session host in Azure Virtual Desktop?
A session host is a VM in Azure that’s part of a host pool and is responsible for running the remote desktop session for the end user.
Is it possible to mix Windows Server and Windows 10 session hosts in the same host pool?
No, mixing Windows Server and Windows 10 session hosts in the same host pool in Azure Virtual Desktop is not supported.
What is the role of application groups in host pools architecture?
Application groups in host pools manage which applications are available to the users connecting to the host pool. A host pool can have multiple application groups.
What is the difference between a desktop application group and a remote application group?
A desktop application group provides a full desktop experience to the user. A remote application group allows users to run a set of applications remotely without a full desktop experience.
Which Azure services are required to create a host pool?
The Azure services required to create a host pool are Virtual Networks, Azure Active Directory, Virtual Machines and Azure Resource Groups.
Can you change a host pool type after it’s created?
No, once a host pool is created, you cannot change its type. You’ll have to create a new host pool if you need to use a different type.
What is the significance of host pool metadata in Azure Virtual Desktop?
The host pool metadata provides detailed information like the host pool type, location, Maximum session limit, Load Balancer type, etc. This information is used by Azure Virtual Desktop to manage and monitor the host pool.
Can usage of host pools lead to cost savings in Azure Virtual Desktop?
Yes, using host pools can lead to cost savings in Azure Virtual Desktop by sharing VM resources among multiple users (in pooled type) or turning off VMs when not in use.
What is the “Start VM on connect” feature in Azure Virtual Desktop host pools?
The “Start VM on connect” feature in Azure host pools allows a VM to be started automatically when a user tries to connect. This helps in resource management by keeping VMs turned off until they’re needed.
How does Failover behavior work in Azure Virtual Desktop host pools?
Failover behavior in Azure host pools ensure that if a session host fails, the user connections are moved over to another session host in the host pool. This ensures continuous availability for users.
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