Oh! it is been a month i haven’t written a single post. Ah! Blogging is my favorite activity. I love sharing my experience and learning. This the single most platform I can express my thoughts on technical front. I don’t know how many of you like but I don’t see that as motivation factor. In all cases I would love to hear back from you. Recently I did a VDI requirement gathering workshop with a customer. Based on various design meeting I have come across questionnaire. I would like to share with you. You will need to basic understanding VDI especially technology you are supporting. First and foremost and most important why are you looking towards VDI. Don’t start with Why question. Rather I suggest you put across a question in way a your customer understands. It is worth noting first meeting will be with IT manager, CXO. They would understand if you ask them what is the primary objective in exploring VDI options.
What is the business goals/Drivers for VDI?
Security, Cost saving, desktop refresh. These are few of the options which can help you to drive the discussion. Without understanding each of the Business drivers your conversation will be more like Q&A. It should be discussion. If desktop refresh is one of the drivers, then immediate question would be to understand if existing desktops can be reused. Are the existing desktop end of life. Since existing desktop will be used, it is very likely user might use both the desktop. It is opportunity to ask where users will be saving their data. It would also give you insight that you need some profile migration tool in place. Since we are here, whether users are using PST and if they are storing in some central location. Here is reference on this topic. This post also provide you likely solutions
What applications will be used via VDI Desktops and What is the nature of this application?
This is most important thing I learnt from Brian Suhr book. VDI is all about apps and not about desktops alone. How you present Applications (apps) to the end user. iPad, Tablets,Phone and Cars is of utmost important. Entire focus of your discussion should around these applications. Who is using these application and what they are doing with these applications. Are there is common set of applications used across your organization? Are there heavy graphics, High I/O (Autocad, Visual Studio), Memory Intensive CPU intensive (Graphics), Recording Audio application in used. Are these application business specific, can these application be down? This discussion will help you decide 1.) if you need a multiple desktop pools 2) Do you need any application virtualization feature. This could be easily guessed, more variation in applications portfolio, more will be inclination to separating application from desktop pool . Most frequently used application can be part of standard image or can be thin app’ed. This is very well explained in Brian’s book. In each case you need to the count of users who are using this application. e.g. If photoshop users are only 5 and they just use it for light graphics you probably don’t need grid cards. If these are heavy graphic users along with considerations of Grid cards, you are very likely to consider to Monitor size and resolution. You could see how one question leads to answer to another. Now that you understand the nature of application, most critical part is how license works. e.g. Office licenses need validation and it need license management server (KMS).
Are there any users who need to install applications on local desktops other than desktop admins?
Now this is one of the use case for persistent desktops. If there are developers in your organization who need pool of applications, they obviously need administrator access and much more. As could be easily guess, you must know how many developers/users with this requirement are needed. This will drive the DR strategy for persistent desktops. Along with, you need to know how critical is their nature of work. Here you can pause and ask how frequently application refresh occurs and how applications are refreshed. This is critical piece of information as these will impact application virtualization and it’s efforts need to update. e.g. If application-A is refreshed every month (yes there are applications which are refreshed every month), and if you are proposing application virtualization for these set of application, you need to consider how are you going to ensure these updates are integrated. This is on-going cost and may vary based on complexity of application. yes I’m reading your mind “App Volumes”. Yeah!, do you need to be architect to say/propose it. Think again!!!
Are users working in shift?
If yes, what is anticipated concurrent users. This will help you decide licenses for VDI and CALs. This will also help you decide % of users who need floating desktops. e.g. if there are 300 users working in a 3 shifts, i.e. 100 users per shift. You just need 100 Concurrent user licenses, you can provide 5% allowances and procure licenses. Floating desktops is must here. CALS refer to end user CALS for desktops or RDSH if you are offering RDSH based desktops. This could be also appropriate place to understand if Terminal services licenses are there with customer
What is anticipated total users (if they are not shift users)?
This will help you identify license requirement for AV, Software licenses for Office, Desktops and other product which do not based their licensing concurrent users. You could relate difference between 300 licenses or 100 AntiVirus license.
From where end users are going to access desktops/applications?
This help you understanding how access has to be granted to the end users e.g. WAN/LAN/Internet. If there are Multiple sites, what is the required bandwidth between these sites. How users are going to access from the remote site. (thin client/Desktop/Laptop). Internet: They could be mobile users, working from home or working from office. Number of users, number of applications they need to access will have direct impact on bandwidth and latency required
Do you need access to desktop from home?
Yes it is not application access but desktop access. If yes, there is whole lot of security considerations. You need view security server or identity access appliance. Identity access appliance would be suitable if there is sufficient VMware Infrastructure in DMZ. All users would need access from Home? Do users needs two factor authentication? if Yes, RSA token is license per user. Is access from Home critical? or it is access on best effort basis. It will drive your high availability design. Again you will need restrict VDI Desktops to specific VLAN
Is user using Lync/Audio/Video user ?
Lync will have direct impact on selection of thin client. It must support Lync plug-in. Zero client definitely do not support it. Factors like features, cost, Design and performance.
Do you need USB devices/Scanner/SmartCard Readers redirection?
This is often forgotten. User need USB devices for various reason. It must be able to accommodate this requirement. In hospitality industry things become more critical when they need to move between room attending patients. This requirement will have indirect impact on your selection of endpoint device.
List down the agent installed on the desktop
- AV Agent
- Backup Agent
- SCCM/LANDesk Agent3
Do you still needs these agents in VDI Desktops? Backup Agent? definitely not. You no longer would be taking desktop backups. would you?
Following questions will help you build supporting infrastructure
- Do you have Certificate Authority? If no, you either have to recommend one to be prerequisite(read this post from Harsha) or assist them in building one
- Do you have Load balancer in your existing solution? If no, you can either procure on behalf of them or ask them to in pre-requisite list? If they need active active VDI solution, then Load balancer should be intelligent to divert traffic based on source IP
- Do you have SRM? If DR strategy is Active-Passive, then SRM will assist in DR failover to VDI components. Refer this white paper for further details
- Do you have terminal server licenses? If yes, you can explore the possibility of providing RDSH to the customer for select applications
- Where users are storing data? local desktop/laptop? then you must considered file server in your design for user data and probably for PST as well.
- Do you have DHCP server at site? Is it redundant?
- Are there any non-corporate users accessing desktops? e.g. Vendor, contractors? How these users prohibited from accessing corp data?
- How are using connecting to the network? These will have direct impact on users endpoint.
This is just the tip of iceberg. If you follow this questionnaire, I’m sure you can built your own based on your experiences. Biggest advantages of this questionnaire is, it allows you to build requirement gathering document without much effort.