Car sharing, leasing or owning a car — which cloud model suits you
SaaS, PaaS, IaaS: three abbreviations that appear in every cloud presentation and that hardly anyone explains. At heart there is only one question — how much do you want to do yourself, and how much should someone else do for you?
Anyone who needs a car has three options: car sharing, leasing or buying. All three get you where you are going. They differ in how much you have to arrange yourself — and how much freedom you get in return.
Cloud services work the same way. SaaS, PaaS and IaaS are not technologies you choose between because one is more modern. They are operating models: They determine where the provider’s responsibility ends and yours begins.
That sounds like a contractual detail. In practice it decides how many people you need to run it, how quickly you can change something — and whose phone rings when something fails at night.
The analogy
Three ways to get there
Get in and drive
The car is waiting, fuelled, serviced and insured. You decide only where it goes. Someone else takes care of tyres and servicing — you do not even find out when it happens.
The price of that convenience: you drive whatever model is standing there. Fitting a tow bar is not an option.
A say, within a fixed frame
You choose the model, the engine and the trim. The vehicle is yours for the term, you drive it daily and set it up as you like. But the basic framework is fixed, and for the big jobs there is the garage.
More room to shape things than with car sharing — in return you carry more responsibility for keeping it in good order.
Full control, full responsibility
The vehicle is yours. You decide everything — and you look after everything: servicing, repairs, tyres, garage appointments. If it will not start in the morning, that is your problem.
In return, nobody can tell you what you may modify.
A note on placing this: Citrix and Omnissa are not themselves IaaS offerings. Their control plane is run by the vendor as a service — but the workplaces beneath it run on virtual machines that you are responsible for. In the analogy: your own car with a service contract attached.
And the fourth option? Your own data centre corresponds not only to owning the car — but to owning the garage, the filling station and the workshop as well.
Responsibility in detail
Who does what — layer by layer
The analogy helps you start. For planning you need the actual division: which layer does the provider run, and which stays with you? From the bottom upwards, responsibility shifts a little further towards you with each model.
| Layer | Windows 365SaaS | Azure Virtual DesktopPaaS | Citrix / Omnissa on AzureIaaS | Your own data centreOn-Premises |
|---|---|---|---|---|
| Identities and accounts | ||||
| Users’ devices | ||||
| Anwendungssicherheit | ||||
| Operating system and updates | ||||
| Configuration of the deployment | ||||
| Network control | ||||
| The virtualisation control plane | ||||
| Physical servers | ||||
| Physical network | ||||
| Data centre and building |
Presentation: our own mapping, based on the responsibility models of the respective providers and focused on the digital workplace context. Contractual arrangements in individual cases may differ.
Two rows stand out: identities and devices stay with Ihnen in every model — even the most convenient one. Anyone who believes a SaaS service hands over responsibility for security is mistaken at exactly the point where most incidents begin.
The same applies to application security: with Windows 365, Microsoft runs the platform, but which applications are installed on it, how they are configured and whether they are kept current remains your affair. That is why it says shared responsibility — the row most often overlooked in projects.
And no model is better than another. A shift worker with three applications does not need to own a car. A CAD engineer with specialist hardware is poorly served by car sharing. That is why every decision starts not with the technology but with the question of who actually works with what.
What follows from this
The model decides your calendar
The choice of service model is often treated as a cost question. It is above all a staffing question. Every layer that stays with you needs someone who understands it, monitors it and repairs it when it fails — at night, at weekends, during holidays.
An example: when Microsoft ships an operating system update, with Windows 365 that is a notice to take note of. With Azure Virtual Desktop it is a procedure involving a test phase, a gold image update and a maintenance window. In your own data centre hardware planning comes on top.
Conversely: the more you hand over, the narrower the frame becomes. Special cases that cost an hour when you run things yourself are sometimes simply not vorgesehen.
The right question is not „what is the most modern?“ but „which responsibility do we want to carry, and which can we?“
Technology that is understood
My standard as an architect is not that a solution works — that is the minimum. It should be comprehensible: every decision has to be explainable in a single sentence that someone who does not work with virtualisation every day can follow. If the management cannot explain why they chose a model, the advice was incomplete.
The car analogy is a start. It does not replace architecture work — but it does make sure everyone at the table is talking about the same thing.
Continue the discussion
This article is part of Workplace Decoded.
I share analyses, frameworks and comparisons on the digital workplace — vendor-neutral and evidence-based. If you see the division of responsibility differently, or want to add from your own experience, LinkedIn is the quickest route to a conversation.
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