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VCAP7-DTM Design Exam, Part 10

In part 10 of my VCAP7-DTM Design exam series we take a look at the Horizon 7 Enterprise Reference Architecture.

To be honest, I didn’t study that much the last two weeks but I checked a few documents about App Volumes, Mirage, ThinApp and User Environment Manager.

This time I would like to summarize what I have learned from the reference architecture and the VMworld 2018 session called Architecting Horizon 7 Enterprise: The Official Reference Architecture (WIN3451BUR).

I only focus on the component design part since I already covered topics like use cases, business drivers, design methodology etc.

Horizon 7

A successful deployment depends on good planning and a very good understanding of the platform. The core elements include Connection Server, Composer, Horizon Agent and Horizon Client. Part 4 to part 9 cover the Horizon 7 component design and also provide more information on the following components.

Horizon 7 Logical Architecture

Identity Manager

VMware Identity Manager (VIDM) can be implemented on-premises or in the cloud, a SaaS-based implementation. If you decide to go with the SaaS implementation, a VIDM connector needs to be installed on-prem to synchronize accounts from Active Directory to the VIDM service in the cloud.

If cloud is no option for you, you still have the possibility for the on-prem deployment and use the Linux-based virtual appliance. There is also a Windows-based installer available which is included in the VMware Enterprise Systems Connector. VMware’s reference architecture is based on the Linux appliance.

VMware Identity Manager Architecture

Syncing resources such as Active Directory and Horizon 7 and can be done either by using a separate VMware Identity Manager Connector or by using the built-in connector of an on-premises VMware Identity Manager VM. The separate connector can run inside the LAN in outbound-only connection mode, meaning the connector receives no incoming connections from the DMZ.

VIDM comes with an embedded PostgreSQL database, but it’s recommended to use an external database server for production deployments.

For high availability, based on your requirements, at least two VIDM appliances should be deployed behind a load balancer. After you have deployed your first appliance, you simply clone it and assign a new hostname and a new IP address.

App Volumes

As you still may know from part 8, App Volumes has two functions. The first is the delivery of applications for VDI and RDSH. The second is the provision of writable volumes to capture user-installed applications and the user profile.

app volumes architecture

For high availability, always use at least two App Volumes Managers which are load-balanced.

AppStacks are very read intensive, hence, you should place AppStacks on storage that is optimized for read operations. Writable volumes should be placed on storage for random IOPS (50/50). There reference architecture uses vSAN to provide a single highly available datastore.

For the SQL database it is recommended using an AlwaysOn Availability Group.

User Environment Manager

When User Environment Manager design decisions need to be made, you have to think about user profiles (mandatory, roaming, local) and folder redirection. As already described in part 9, VMware recommendation is to use mandatory profiles and folder redirection. Use appendix B if you need help configuring the mandatory profile.

vmware user environment manager

The first key design consideration is using DFS-R to provide high availability for the configuration and user shares. Note: Connect the management console only to the hub member when making changes. DFS-R will replicated those changes to the spoke members.

The second consideration one is using GPO loopback processing.

Unified Access Gateway

In part 6 I mentioned that a UAG is typically deployed within the DMZ.

VMware Unified Access Gateway

UAG appliances are deployed in front of the Horizon 7 Connection Servers and sit behind a load balancer. The Unified Access Gateway also runs the Content Gateway as part the AirWatch (WorkspaceONE UEM) service.

You have two sizing options during the appliance deployment:

  • Standard (2 vCPU, 4GB RAM, 2’000 Horizon server connections, 10’000 AirWatch service connections)
  • Large (4 vCPU, 16GB RAM, 2’000 Horizon server connections, 50’000 AirWatch service connections)

As you can see, the big difference here are the estimated AirWatch service connections per appliance. In production you would deploy dedicated UAG appliances for each service. Example:

  • 2 standard size UAGs appliances for 2’000 Horizon 7 sessions (n+1)
  • 3 large size UAG appliances for 50’000 devices using Content Gateway and per-App Tunnel which gives us a total of 100’000 sessions. The third appliance is for high availability (n+1)

vSphere and Physical Environment

The software-defined data center (SDDC) is the foundation that runs all infrastructure servers and components. The products and the licensing for the foundation are outside of the Horizon 7 product (except vSAN), but are required to deliver a complete solution.

And in my opinion this is what makes the whole solution so brilliant. Even I work for VMware, I would never say from the beginning that Horizon is better than XA/XD. This was also the case when I worked as a consultant for Citrix before I joined VMware in May 2018.
It depends on the requirements and use cases which need to be satisfied. That are the most important things if you choose a vendor or a specific technology. Our goal is to make the customer happy! 🙂

But I would say that VMware Horizon including WorkspaceONE is very hard to beat if you use the complete stack! But that’s another topic.

The vSphere infrastructure in the reference architecture includes vSAN and NSX. In part 5 I covered the basics of vSAN, but I think I maybe need to write a short overview about NSX and how you can use it with Horizon.

vSAN provides a hyper-converged storage optimized for virtual machines without the need for an external SAN or NAS. This means that the physical server not only provides the compute and memory resources, but also storage in a modular fashion. You can use vSAN for the management and resource block  and follow a hybrid approach for the management resources and use all-flash vSAN for the Horizon resources.

VMware vSAN

I will not cover the vSphere design, but it’s important to understand that all components are operating redundantly and that you have enough physical resources to meet the requirements.

vSphere Networking

A general recommendation is to use at least 10 GbE connections, to separate each traffic (mgmt, VM traffic, vSAN, vMotion) and make sure that each of them has sufficient bandwidth.

NSX for vSphere

NSX provides several network-based services and performs several security functions within a Horizon 7 implementation:

  • Protects VDI infrastructure
  • Protects desktop pool VM communication with applications
  • Provides user-based access control (user-level identity-based micro-segmentation)

VMware NSX for vSphere

If you want to use NSX you have to think about a NSX infrastructure design as the NSX platform adds new components (e.g. NSX manager) and new possibilities (distributed firewall and identity firewall).

The most important design consideration for Horizon 7 is the concept of micro-segmentation. In the case of Horizon 7, NSX can block desktop-to-desktop communications, which are normally not needed or recommended. Each VM can now be its own perimeter and this desktop isolation prevents threats from spreading:

NSX isolation

The Horizon 7 reference architecture of probably the best document to prepare yourself for the VCAP7-DTM exam. What do the current VCAP7-DTM certified  people say? What else needs to be covered? Jump to part 11

VCAP7-DTM Design Exam, Part 6

This is the sixth part of my VCAP7-DTM Design exam series. In part 5 I covered the creation of a physical design for horizon storage. This time we take a look at section 5 of the blueprint, the creation of a physical network design for Horizon:

Section 5 – Create a Physical Design for Horizon Networking
Objective 5.1 – Plan and Design Network Requirements for Horizon solutions (including Mirage and Workspace One)
Objective 5.2 – Design Network and Security Components Based on Capacity and Availability Requirements
Objective 5.3 – Evaluate GPO and Display Protocol Tuning Options Based on Bandwidth and Connection Limits

Networking is also a very important and exciting when creating a Horizon architecture and a lot of questions are coming up when I think about Horizon and network access and devices:

  • How does the ISP infrastructure look like?
  • Do we have redundant internet uplinks?
  • Bandwidth in the data center?
  • Firewalls?
  • Remote connections?
  • How is the connection between Horizon client and agent?
  • ESXi host network interfaces?
  • Do we have mobile workers using WLAN?

I once had a customer who had a really nice and modern data center infrastructure, but their firewalls didn’t provide enough throughput. Make your homework and know how the routing and switching looks like and check every component’s limit.

Beside our VDI traffic, what about management, vMotion and vSAN traffic? Do we have enough network interfaces and bandwidth? If you think about management traffic, then 1Gbit interfaces are normally sufficient. But vMotion and vSAN traffic should have redundant 10Gbit connections and be on different subnets/VLANs.

Overview of the Network Architecture

In most network architectures two firewalls exist to create the DMZ.

The Unified Access Gateway (UAG) appliances are placed in the DMZ. UAG can perform authentication or pass a connection to the Connection Server for AD authentication.
Notauthenticated sessions are dropped at the Unified Access Gateway appliance and only authenticated sessions are allowed to connect to the internal resources.

UAG appliances in the DMZ communicate with the Connection Server instances inside the corporate firewalls and ensure that only the desired remote apps and desktop sessions can enter the corporate data center on behalf of this strongly authenticated user.

Inside the corporate firewall you install and configure at least two Connection Server instances. Their configuration data is stored in an embedded LDAP directory (AD LDS) and is replicated among all members of the group.

Firewall Ports

On March 22, 2016, an updated network ports diagram has been posted by VMware:

Horizon 7 Network Ports Diagram

On Tech Zone this diagram and all key firewall considerations are available for Horizon 7:

Network Bandwidth Considerations

The used session bandwidth between the Horizon client and agent depends highly on the session configuration. For display traffic, many elements can affect network bandwidth, such as the used protocol, monitor resolution, frames per second, graphically intense applications or videos, image and video quality settings.

Because the effects of each configuration can vary widely, it’s recommended to monitor the session bandwidth consumption as part of a pilot. Try to figure out the bandwidth requirements for each use case.

Display Protocol

I would say that Blast Extreme is the way to go, because it has been optimized for mobile devices and can intelligently switch between UDP and TCP (Adaptive Transport). PCoIP has been developed by Teradici, but Blast is VMware’s own creation and that’s why I think that Blast will be “the future” and that RDP still can be used as fallback for some special scenarios.

Display Protocol Tuning Options

I will not cover this topic and explain you how you can configure the maximum bandwidth for PCoIP via GPO. There are several options to decrease and increase the used session bandwidth:

Configuring PCoIP session variables
VMware Blast Policy Settings

WAN Consideration

Nowadays, every client device is connected with 1Gbps. LAN connections and the user experience are most of the time perfect. How is it with WAN connections where you will have latencies that could be between 50 and 200ms? Do you apply Quality of Services (Qos) policies to prioritize Horizon traffic?

WAN optimization is one of the keywords when talking about WAN connections and is valuable for TCP-based protocols which require many handshakes between client and server, such as RDP.
PCoIP is  UDP-based and this was the reason why everyone in the past said, that you should prefer this protocol for connections with higher latencies and then no WAN optimization or acceleration would be needed.

Then inside the corporate network you would use RDP because your network is stable or did you leave this choice to the user?

With Blast Extreme, Adaptive Transport will automatically detect higher latencies and automatically switches between TCP and UDP if needed. Higher latencies could also occur with mobile devices working of WiFi networks.

In my opinion there are almost no reasons anymore to use anything else than Blast because it’s also more network efficient than PCoIP.

pcoip blast extreme comparison


Use separate networks for vSphere management, VM connectivity, vMotion and vSAN traffic. Make sure you have redundancy across different physical adapters (NIC, PCI slot) and devices (switches, router, firewall). Consider the use of a vSphere Distributed Switch (vDS) to reduce management overhead and provide a richer feature set. Maybe NSX could be interesting for micro segmentation.

Load balancing is a very important component of a Horizon architecture. The primary purpose of load balancing is to optimize performance by evenly distributing client sessions across all available Connection Server instances. The same is valid for UAG appliances, Identity Manager or App Volumes Manager. NSX comes with a virtual load balancer, but F5 and NetScaler are also fine.

Depending on your customer’s requirements and needs, the network design is another key part to remove single point of failures.

In part 7 we will figure out how we have to design Horizon desktops and pools.