Question 629 of 997
Monitoring, Logging and Runtime SecuritymediumMultiple ChoiceObjective-mapped

crictl ps No Output: Fixing Runtime Endpoint

This CKS practice question tests your understanding of monitoring, logging and runtime security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

You run 'crictl ps' and see no output, but the node has running pods. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

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 --runtime-endpoint flag is not set or points to the wrong socket

The `crictl ps` command queries the container runtime via the CRI (Container Runtime Interface) socket. If it returns no output while the node clearly has running pods (visible via `kubectl` or `kubelet`), the most likely cause is that the `--runtime-endpoint` flag is not set or points to the wrong socket. By default, `crictl` uses `/var/run/dockershim.sock` (deprecated) or may fall back to an incorrect path; if the actual runtime socket (e.g., `/run/containerd/containerd.sock` for containerd, or `/var/run/crio/crio.sock` for CRI-O) is not specified, the tool cannot connect to the runtime and returns an empty list.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume `crictl ps` shows all containers on the node, but it only shows containers managed by the CRI runtime at the specified endpoint — if the endpoint is misconfigured, it returns nothing even though pods are running.

Detailed technical explanation

How to think about this question

Under the hood, `crictl` communicates with the runtime over a Unix domain socket using the gRPC CRI protocol (defined in the Kubernetes CRI spec). If the socket path is wrong or the runtime is not listening, the gRPC call fails silently or returns an empty list. In real-world scenarios, this often happens when migrating from Docker to containerd or CRI-O — the default socket path changes, and `crictl` must be configured via the `--runtime-endpoint` flag or the `CRI_CONFIG_FILE` environment variable pointing to a `crictl.yaml` file.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A practitioner preparing for the CKS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this CKS question test?

Monitoring, Logging and Runtime Security — This question tests Monitoring, Logging and Runtime Security — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The --runtime-endpoint flag is not set or points to the wrong socket — The `crictl ps` command queries the container runtime via the CRI (Container Runtime Interface) socket. If it returns no output while the node clearly has running pods (visible via `kubectl` or `kubelet`), the most likely cause is that the `--runtime-endpoint` flag is not set or points to the wrong socket. By default, `crictl` uses `/var/run/dockershim.sock` (deprecated) or may fall back to an incorrect path; if the actual runtime socket (e.g., `/run/containerd/containerd.sock` for containerd, or `/var/run/crio/crio.sock` for CRI-O) is not specified, the tool cannot connect to the runtime and returns an empty list.

What should I do if I get this CKS question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jul 4, 2026

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This CKS 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 CKS exam.