Quick Note — Recommend a Serverless-Based Solution
AZ-305 › Unit 4: Design infrastructure solutions › Design compute solutions › Recommend a serverless-based solution
Quick Note — Recommend a Serverless-Based Solution
A fintech team builds a webhook receiver for a payment provider. Volume is bursty — silent for hours, then events in two minutes when reconciliation runs. The team originally builds it on a 2-instance App Service plan (/month, always on). The bill is fine, but the architect asks two questions during review: "What happens when reconciliation overlaps with a partner integration burst?" and "Why are you paying $24/7 for a workload that runs 4 hours a day?". A redesign onto `Azure Functions` Consumption plan cuts the bill to $$\sim $3/month and removes the capacity-overlap risk entirely. The Functions plan handles a 50{}$ burst without intervention.…
Retrieval target
- Recommend a Serverless-Based Solution
- Closed-book recall
- 5 minutes
- Open the full lesson after a miss
Decision anchors
| Prompt | Compact answer |
|---|---|
Azure Functions | An event-driven serverless compute service. Write a function (Node, .NET, Python, Java, PowerShell), attach a trigger (HTTP, Timer, Blob, Queue, Event Grid, Service Bus, Cosmos, Event Hub), and the platform invokes it. Adjacent bindings wire inputs and outputs (Storage, Cosmos, Service Bus) without manual SDK code. Pay-per-execution + per-GB-second on Consumption; per-instance on Premium/Dedicated. |
Functions Consumption plan | True serverless Functions plan: scale-to-zero, pay only for executions (1M free + GB-s / month). Auto-scales to 200 instances max, cold start can be seconds, function timeout default 5 min, max 10 min (configurable). No VNet integration by default (Flex Consumption is the modern variant that adds VNet + warmth). Pick for spiky / bursty / dev / low-volume. |
Functions Premium plan | Functions running on pre-warmed instances: no cold start, VNet integration built-in, longer execution time (no 10-min cap), more memory (14 GB). You pay for the pre-warmed instance (24/7) plus consumption above it. Pick when you need predictable latency, VNet access to private resources (DB, App Gateway), or long-running functions ( min). |
Functions on the App Service (Dedicated) plan | Functions sharing an App Service Plan with web apps — runs on plan VMs you've already paid for. No serverless properties (no scale-to-zero, no per-execution pricing). Useful when you have spare ASP capacity and want to colocate a small function with an app. Pick only when you can't justify Premium or Consumption — i.e., when the ASP is already paid for. |
Read the answers once, then cover the right-hand column and reconstruct each one from the prompt. A useful answer names the requirement, the recommended control or service boundary, and the nearest alternative it rejects. If you can only recognize the answer after seeing it, retrieval is not yet secure.
Ninety-second explanation
Without notes, explain:
- What requirement signals this learning objective rather than a neighbouring one?
- Which two solution families are most likely to be compared?
- Which hard constraint eliminates the strongest distractor?
- What identity, network, data, or failure boundary must appear in the design?
- Which operational test would prove the recommendation works?
Then compare your explanation with the full lesson. Record the missing decision rule—not merely the missed product name—in your error log.
When to open the full lesson
Open the curriculum-linked lesson when you cannot explain a comparison, when a scenario depends on a numeric limit or SKU feature, or when the service is on a retirement path. Use current Microsoft Learn documentation for availability, limits, pricing, naming, and migration milestones; the quick note is intentionally compact.
Source and freshness
Derived from the linked AZ-305 lesson and retrieval deck, grounded in both attached course sources. Reviewed 2026-08-02. Current Microsoft documentation controls changing product contracts.