CKAD Application Design and Build Practice Question
Which TWO statements about init containers are true?
⚠ Common exam trap
Candidates often confuse init containers with sidecar containers, thinking they run in parallel with regular containers, but Kubernetes explicitly runs init containers sequentially and to completion before any regular containers start.
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
✓
Init containers run to completion before any regular containers start.
Init containers are designed to run to completion before any regular containers in the Pod start. This ensures that prerequisites (e.g., database schema migrations, configuration file generation, or waiting for a service to become available) are satisfied before the main application containers begin execution.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Init containers run to completion before any regular containers start.
Why this is correct
Init containers are a distinct type of container in a Kubernetes pod that are started first, and each must run to completion (exit code 0) before any regular container in the pod is launched. The kubelet ensures that all init containers finish successfully before the main application containers are created, making them a gate for prerequisites. If an init container fails, it is restarted according to the pod's restartPolicy until it succeeds, and regular containers never start until that happens.
- ✗
Init containers run in parallel with regular containers.
Why it's wrong here
This statement is false because init containers are explicitly executed in a separate phase that precedes the regular containers; regular containers are only started after all init containers have completed successfully. There is no overlap in execution: an init container and a regular container cannot be running simultaneously in the same pod. Moreover, even among init containers themselves, they run sequentially rather than in parallel, so concurrency is not a feature of init containers.
- ✓
Init containers run sequentially, one after another.
Why this is correct
Init containers run strictly in the order they are defined in the pod spec, one after another. The kubelet starts the first init container, waits for it to exit with code 0, then starts the next init container, and so on. This sequential behavior is fundamental to their use case, allowing you to execute setup steps in a specific, deterministic order before the main containers start.
- ✗
Init containers must use the same image as the main container.
Why it's wrong here
This statement is incorrect because Kubernetes allows each init container to use a different image, and there is no requirement for it to match the image of the main container. This flexibility is intentional—init containers often use lightweight or specialized images (e.g., busybox, a curl image, or a custom utility) to perform setup tasks while the main container uses its own runtime image. The pod spec can list multiple init containers with totally different images, and that is perfectly valid.
- ✗
Init containers cannot access volumes shared with regular containers.
Why it's wrong here
This statement is false because init containers share the same pod-level volumes as regular containers, since they are part of the same pod definition. By mounting the same volume in an init container, you can pre-populate files, set permissions, or fetch data that the main container will later use—this is a common pattern. The pod spec allows you to declare volumes and then mount them in both initContainers and containers, so there is no restriction on volume access for init containers.
Go deeper
Related to this question
About these practice questions
Courseiva writes every CKAD question from scratch — 826 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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.