Exercise 2: Why "Zone 1" Isn't the Same Datacenter Across Subscriptions — Possible Solution
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Azure maps each physical datacenter to a logical zone number (Zone 1,
Zone 2, Zone 3) on a PER-SUBSCRIPTION basis, not on a single, shared,
provider-wide basis. This means the specific physical datacenter
behind "Zone 1" is determined independently for each subscription --
Subscription A's own Zone 1 might correspond to a genuinely different
physical building than Subscription B's own Zone 1, even in the exact
same Azure region.

The real, practical implication for two teams deliberately trying to
co-locate resources for low latency: if Team A deploys resources into
"Zone 1" under their own subscription, and Team B deploys resources
into "Zone 1" under a separate subscription, there is no guarantee
those two "Zone 1" deployments are actually in the same physical
datacenter at all -- despite sharing the same zone number, they could
be kilometers apart, with real, ordinary inter-zone latency between
them rather than the co-located latency the teams were hoping to
achieve.

ANSWER: Because zone-number-to-physical-datacenter mapping is assigned
independently per subscription, two subscriptions' own "Zone 1" can
genuinely refer to different physical locations. For two teams to
reliably co-locate resources, they cannot simply agree to both use
"Zone 1" -- they need to explicitly check and compare their own real
physical-to-logical zone mappings (via the Azure CLI, PowerShell, or
the Resource Manager API) to confirm they're actually targeting the
same physical zone before deploying.

WHY THIS WORKS AS AN ANSWER
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This correctly explains the real mechanism behind the quirk
(per-subscription mapping, not a shared global one) and translates it
into a concrete, practical consequence for a realistic multi-team
scenario, rather than just restating that the mapping "can differ"
without explaining what that means for anyone trying to actually use
it.