This CKA practice question tests your understanding of cluster architecture, installation and configuration. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
What is the default port for the Kubernetes API server?
10250
Why wrong: Port 10250 is used by kubelet for its API.
8080
Why wrong: Port 8080 is often used for insecure API server access, but the default secure port is 6443.
2379
Why wrong: Port 2379 is used by etcd for client connections.
6443
The API server listens on port 6443 by default for secure HTTPS connections.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
6443
The Kubernetes API server defaults to port 6443 for secure HTTPS traffic. This is the standard port used by kubectl and other clients to communicate with the control plane over TLS-encrypted connections, as defined in the Kubernetes documentation and default kube-apiserver configuration.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
10250
Why it's wrong here
Port 10250 is used by kubelet for its API.
8080
Why it's wrong here
Port 8080 is often used for insecure API server access, but the default secure port is 6443.
2379
Why it's wrong here
Port 2379 is used by etcd for client connections.
6443
Why this is correct
The API server listens on port 6443 by default for secure HTTPS connections.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse the deprecated insecure port 8080 with the default secure port 6443, especially if they have experience with older Kubernetes versions or minikube setups that might expose port 8080 locally.
Detailed technical explanation
The API server listens on port 6443 for HTTPS, using TLS certificates to authenticate and encrypt all traffic. In a production cluster, the insecure port (8080) is typically disabled via the `--insecure-port=0` flag, and all client requests must go through port 6443, which is also the port used by kube-proxy and other components for service discovery and proxying to the API server.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CKA 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
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FAQ
Cluster Architecture, Installation and Configuration — This question tests Cluster Architecture, Installation and Configuration — Read the scenario before looking for a memorised answer..
The correct answer is: 6443 — The Kubernetes API server defaults to port 6443 for secure HTTPS traffic. This is the standard port used by kubectl and other clients to communicate with the control plane over TLS-encrypted connections, as defined in the Kubernetes documentation and default kube-apiserver configuration.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This CKA 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 CKA exam.
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