Measure What the Operator or User Actually Cares About
CPU and container counts are supporting signals; service reachability, backup validity and call-path health are closer to the real objective.
TOPIC
Observability
Lessons, explainers, experiments, and implementation notes.
Health Probes Should Not Follow Redirects Blindly
A probe that follows a redirect can report success for the wrong endpoint and hide an authentication or routing failure.
cAdvisor Used 428 MiB Until We Asked What We Actually Needed
Observability can become the workload if collection is broader than the questions operators actually need to answer.
A Five-Minute Cache Was the Right Place for Expensive Docker Storage Inventory
Not every metric needs to be collected at the same cadence; expensive inventory can be cached without weakening real-time health signals.
Metric Cardinality Is a Capacity Problem Disguised as a Naming Problem
Labels make dashboards flexible, but uncontrolled label values multiply time series and memory cost quickly.
Disabling One Metric Family Can Be Better Than Tuning the Whole Monitoring Stack
The fastest observability optimization came from identifying one costly collector instead of globally lowering fidelity.
Stale Telemetry Should Not Render as Healthy
A last-known-good value becomes misleading when the system does not show how old the evidence is.
Wi-Fi Signal Needed Two Measurement Paths, Not One Assumption
Hardware and drivers expose radio state differently, so a production metric may need a fallback without hiding uncertainty.