What happens when you redeploy an ARM template in incremental mode to a resource group that already contains resources NOT defined in the template?
A.The unlisted resources are deleted
That's COMPLETE mode behavior — the exam loves this trap.
B.Unlisted resources are left unchanged — only template resources are created/updated
Incremental = leave everything else alone. Correct.
C.Deployment fails due to drift detection
Drift doesn't block ARM deployments.
D.Unlisted resources lose their tags
Tags aren't touched on unlisted resources.
Why this answer
Incremental mode (default) adds/updates only what the template defines and ignores everything else. Complete mode is the dangerous one — it DELETES resources not in the template. The incremental-vs-complete distinction is a classic exam point.
Correct answer: B · Last reviewed 2026-02-14
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