Short, honest write-ups of the ideas that come up in interviews and on the job. Each one teaches the concept properly, cites the Microsoft documentation, and points back to the class that drills it until it sticks.
An image is a reusable template for spinning up new, identical VMs; a snapshot is a point-in-time copy of one disk. Here's when to use each, and the exact az CLI and portal steps for both paths.
Nested virtualization is running a hypervisor inside an Azure VM so you can spin up Hyper-V, Windows Sandbox, WSL2, or nested Kubernetes on it. It only works on VM sizes that expose the virtualization extensions — pick the wrong series and it silently won't. Here's what it is, which sizes support it, and how to turn it on.
Microsoft’s container-optimised distro (formerly CBL-Mariner): a small, hardened host OS for AKS nodes. Why it exists, how to choose it, and Ubuntu-vs-Azure-Linux.
The 30-second az webapp up, a static-vs-dynamic decision, custom domain plus free HTTPS, and what it actually costs per month.
What each tier is for, and the feature cliffs — Always On, slots, VNet — that force an upgrade. F1 to P1v3, side by side.
ACI runs a container; Container Apps runs a container service. Burst jobs versus scale-to-zero, cost, and the AKS off-ramp.
Three real options with real monthly-dollar math — and the places where "free" quietly bites you later.
Static and JAMstack go to Static Web Apps; server-rendered apps and backends go to App Service. The full cost and feature split.
Why Free and Shared tiers can't do it, the DNS and verification steps, the free managed cert, and the apex-domain traps.
Kubernetes is a demanding machine to keep alive; AKS is the deal where Azure runs the demanding part for free and you pay only for the boxes your containers actually land on.
Both spread your VMs so one failure doesn't take the whole application down — but a set spreads them across racks inside one building, and a zone spreads them across separate buildings, and that difference is the whole point.
The size picker has hundreds of options with names like Standard_D4s_v5, and most people scroll until something looks big enough — which is how you end up paying for RAM you never touch, or throttling a database that needed it.
A Spot VM can cost a fraction of the standard price for the exact same hardware — but Azure can take it back with 30 seconds notice, mid-job, whenever it wants the capacity. Whether that trade is worth it comes down to one question about your workload.
The default *.azurewebsites.net URL never goes away and lands visitors on the raw app behind your custom domain. You can't delete it and going private breaks the domain — redirect it with one URL Rewrite rule, minding the patternSyntax gotcha.
500.30 means the ASP.NET Core Module launched your app and it crashed during startup. Here's how to tell it apart from 500.31–500.38 and pull the real underlying exception with stdout logging, Log stream, and dotnet App.dll.
Running one VM is easy; running forty identical ones that add and remove themselves with demand is a job you do not want to do by hand. A scale set is Azure doing it from a single image — the building block under autoscale and AKS node pools.
The scariest moment in running a web app is the deploy. Slots turn it into a non-event: push to a warm staging copy, swap it into production with nothing dropped, and swap straight back if the new build misbehaves.
Sizing a server for your worst hour means paying for that hour all day. Autoscale flips it: the app grows instances when the crowd arrives and gives them back when it leaves — the elasticity you moved to the cloud for.
Hosting a web app used to mean owning a server — patching an OS, praying on release night. App Service takes all of that off your plate and leaves the one thing that matters: your code.
Most cloud code spends its life waiting — a server billed by the hour to work for a few seconds a day. Functions flips that: your code sleeps for free, wakes on an event, does its job, and goes back to sleep.
Azure has a shelf of places to run your code, and the beginner mistake is reaching for the most powerful one. The real question is not what can run this, but how much platform your team can actually operate.
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