CKAD Application Design and Build Practice Question
A CronJob has concurrencyPolicy set to 'Forbid'. At the scheduled time, if the previous job is still running, what happens?
⚠ Common exam trap
A common mix-up: candidates confuse 'Forbid' with 'Replace' (which terminates the previous job) or assume Kubernetes will queue the job, but 'Forbid' strictly skips the run without any retry or delay.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The new job is skipped (does not run)
When a CronJob has `concurrencyPolicy: Forbid`, Kubernetes ensures that if a previous job instance is still running at the next scheduled time, the new job is simply skipped (does not run). This prevents overlapping executions, which is critical for workloads that must not run concurrently, such as database migrations or batch processing that would cause data corruption.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The new job is delayed until the previous job completes
Why it's wrong here
This describes behavior that Kubernetes does not implement for CronJobs. The Forbid concurrency policy does not queue or hold the new run until the previous job finishes; delay would require an external workflow or a separate controller. When the scheduled time arrives and the previous Job is still active, the CronJob controller immediately drops the run for that schedule, so it never becomes a pending or delayed Job.
- ✓
The new job is skipped (does not run)
Why this is correct
With concurrencyPolicy: Forbid, the CronJob controller checks for any active Jobs from the same CronJob at the scheduled start time. If one exists, the controller deliberately does not create the new Job, and the scheduled invocation is skipped entirely without being queued or retried. The CronJob can then run again only at its next configured schedule, assuming no overlapping Job is still active.
- ✗
Both jobs run concurrently
Why it's wrong here
Allowing both Jobs to run at the same time is exactly what concurrencyPolicy: Allow does, not Forbid. Forbid exists specifically to prevent overlapping executions, which can be critical for batch jobs that must not run concurrently due to shared state, database locks, or resource limits. Under Forbid, the existence of a current active Job suppresses the new one, so concurrent execution cannot occur.
- ✗
The previous job is terminated and the new job starts
Why it's wrong here
Terminating the previous Job and starting a new one is the behavior of concurrencyPolicy: Replace, not Forbid. In Replace mode, the controller removes the currently running active Job before or as it creates the new one, ensuring at most one Job for that CronJob at a time. Forbid, by contrast, takes no destructive action on the existing Job; it simply omits creating the new scheduled run, allowing the current Job to continue uninterrupted.
Go deeper
Related to this question
About these practice questions
This CKAD question is part of Courseiva's 826-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKAD practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CKAD exam.