Exercise 1: Missing Memory Metrics on a Cloud Monitoring Dashboard — Possible Solution
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Cloud Monitoring automatically collects CPU utilization and disk usage
for Compute Engine VMs with no setup required, which is exactly why
those two are already showing up correctly. Memory usage is not part
of that automatically-collected set - it is one of the detailed
system metrics that requires installing the real Ops Agent on the VM
first, the same real gap this chapter names as recurring across all
three major cloud providers.

Without the Ops Agent installed, there is simply no memory-usage data
being sent to Cloud Monitoring at all, which is why the dashboard
shows nothing for it rather than showing zero or an error - the
metric was never being collected in the first place.

ANSWER: This is happening because memory usage is not part of Cloud
Monitoring's automatically-collected metrics - only CPU and disk usage
are collected by default. The fix is to install the Ops Agent on the
Compute Engine VMs, which is what actually enables memory (and other
detailed) metric collection.

WHY THIS WORKS AS AN ANSWER
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This correctly identifies the specific real automatic-vs-agent-
required metric split the chapter describes, rather than assuming all
system metrics are collected automatically by default.