CKA Practice Question: Cluster Architecture, Installation and Configuration
You are upgrading a Kubernetes cluster from version 1.28 to 1.29. What is the correct order of steps?
⚠ Common exam trap
Watch out — candidates often think upgrading worker nodes without draining is acceptable if they use a rolling update strategy, but the CKA exam specifically tests the requirement to drain nodes before upgrading to avoid pod disruption.
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
✓
Upgrade control plane nodes first, then drain each worker node before upgrading it.
The Kubernetes upgrade process requires upgrading the control plane nodes first to ensure the cluster's management layer is running the new version before worker nodes are upgraded. Draining each worker node before upgrading it is essential to safely evict pods and maintain application availability, as the kubelet on the node must be stopped during the upgrade and the node must be cordoned to prevent new pods from being scheduled.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Upgrade all worker nodes first, then upgrade control plane nodes.
Why it's wrong here
Upgrading worker nodes before the control plane violates Kubernetes version skew policies. The kubelet on a worker node cannot be newer than the kube-apiserver, as the older control plane may not recognize new API fields or behaviors introduced in the newer kubelet version. Therefore, the control plane must always be upgraded first to maintain API compatibility and cluster stability.
- ✗
Upgrade control plane nodes first, then upgrade worker nodes without draining them.
Why it's wrong here
While upgrading the control plane first is correct, failing to drain worker nodes before upgrading their kubelet and container runtime can cause severe workload disruption. Draining safely evicts running pods to other active nodes in the cluster, preventing sudden application downtime and ensuring a graceful termination of stateful or stateless workloads. Skipping this step risks ungraceful pod termination and service outages.
- ✓
Upgrade control plane nodes first, then drain each worker node before upgrading it.
Why this is correct
This sequence aligns perfectly with the official Kubernetes upgrade lifecycle. Upgrading the control plane components first ensures that the API server can handle requests from newer kubelet versions. Subsequently draining each worker node before its upgrade guarantees that workloads are safely rescheduled onto other healthy nodes, minimizing service disruption during the node's maintenance window.
- ✗
Upgrade all nodes simultaneously.
Why it's wrong here
Attempting to upgrade all nodes at the same time will lead to complete cluster downtime and potential data corruption. The control plane must remain operational to coordinate the scheduling and management of workloads while individual worker nodes are being upgraded. A simultaneous upgrade violates version skew limits and leaves the cluster without an active API server to manage the transition.
Go deeper
Related to this question
Learn chapter
Kubernetes Architecture Overview
Key term
Kubernetes Node Roles
Kubernetes Node Roles are labels assigned to machines in a cluster that define whether a node runs application containers (worker) or manages the cluster (control plane).
Key term
Ingress Resources
Ingress Resources are Kubernetes API objects that manage external access to services inside a cluster, typically HTTP and HTTPS traffic, by defining rules for routing requests based on hostnames and paths.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.