# Reflection: The Right Primitive Is a Correctness Decision, Not a Style Choice

You just built a one-shot Job and a scheduled CronJob for real. Take a few minutes to connect
this to production thinking.

## Reflection questions

1. If your team accidentally deployed the database backup script as a Deployment instead of a
   CronJob, what's the FIRST symptom you'd likely notice — and would it look like a bug in the
   backup script itself, or something else?
2. A CronJob that fails silently every night for a week is a real, common incident pattern. What
   would you want monitored to catch this quickly?
3. Why does "it ran once and worked" not prove a CronJob is configured correctly?

## Real Ops takeaway

**Workload-primitive mistakes often look like application bugs at first.** A backup script
"crashing" every few minutes on a Deployment isn't a bug in the script — the script did exactly
what it was told to do (exit when finished) and the Deployment is "correctly" restarting it
according to its own contract. Recognizing "wrong primitive," not "buggy code," as the root
cause saves real debugging time.

**A schedule you never verify is a schedule you can't trust.** A CronJob failing every single
run since deployment is easy to miss if nobody checks — unlike a Deployment's crash-looping
Pods, which are visible in `kubectl get pods` by default, a CronJob's failed history requires
someone to actually look at `kubectl get jobs` or the CronJob's own status. Real teams monitor
CronJob success/failure explicitly rather than assuming silence means success.

This module is complete. Continue to the next module.

## Instructor Notes

**Discussion questions for a live classroom:** question 1 is worth pushing on — many students'
first instinct is to debug the "crashing" script rather than question the workload type it's
running under.

**Approximate timing:** 8 minutes live discussion; 5 minutes self-paced writing.

**Optional extension:** ask students to name one alerting rule they'd add for a critical nightly
CronJob (e.g. "alert if no successful completion recorded in the last 25 hours").