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The 15 things to be sure of

If you remember nothing else, remember these.

1	App Service = PaaS: Azure runs the OS, patching, load balancing and TLS. A VM means you own all of it.
2	The App Service Plan is what you pay for — and apps sharing a plan share its CPU.
3	Scale up = bigger machine (has a ceiling) · scale out = more machines (needs a stateless app).
4	Load Balancer = L4, packets · Application Gateway = L7, URLs + WAF · Front Door = L7 global.
5	Slots: deploy to staging → warm up → swap routing. Zero downtime, and rollback is a second swap.
6	Mark environment-specific settings as slot settings, or the swap points production at the staging database.
7	Code rolls back; data does not. Migrations must be expand-then-contract.
8	Canary = gradual %, smallest blast radius · Blue-green = switch everyone at once, simpler, 2× cost.
9	Alert on the canary's own error rate — the blended figure hides it.
10	Functions = event-driven, scale to zero, cold starts. App Service = steady traffic, full pipeline, no cold start.
11	Elastic pool = many small databases with non-overlapping peaks share one pool of compute.
12	Managed identity = no secret exists to steal. Use it for Key Vault, SQL and Storage.
13	Key Vault is not 100% secure — it protects secrets at rest, not a compromised app. Hence least privilege.
14	App Insights: end-to-end transaction view shows where the time went. Read p95, not the average.
15	CI = build + test · Continuous Delivery = releasable, human approves · Continuous Deployment = no approval.

Words that signal seniority

slot swap · warm-up · sticky slot setting · expand/contract migration · blast radius · canary weight · cold start · managed identity · least privilege · p95 · end-to-end transaction · build once, deploy everywhere