Question 646 of 302
How to Upgrade a Worker Node with Kubeadm
A cluster was upgraded from v1.28 to v1.29 using kubeadm. After upgrading the control plane, nodes remain at v1.28. What is the correct next step to upgrade a worker node?
Quick Answer
The answer is to SSH into the worker node and run `kubeadm upgrade node`, then upgrade kubelet and kubectl, and finally restart the kubelet. This is correct because `kubeadm upgrade node` updates the node’s kubelet configuration and static pod manifests to match the new control plane version, but it does not automatically upgrade the kubelet binary itself—that requires a separate package manager step. On the CKA exam, this task tests your understanding that worker nodes are not upgraded by the control plane’s `kubeadm upgrade apply`; each node must be handled individually, and a common trap is forgetting to restart the kubelet after upgrading its binary. Remember the sequence: drain, upgrade config, upgrade binaries, restart kubelet, uncordon. A helpful mnemonic is “SSH, Node, Binary, Restart” to avoid missing the critical kubelet restart step.
⚠ Common exam trap
A common mix-up: candidates assume simply upgrading the kubelet binary via the package manager is sufficient, but the CKA exam tests the understanding that 'kubeadm upgrade node' must be run first to update the node's configuration and static pod manifests, ensuring a complete and consistent upgrade.
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
✓
SSH into the worker node and run 'kubeadm upgrade node', then upgrade kubelet and kubectl, then restart kubelet.
After upgrading the control plane with kubeadm, worker nodes must be upgraded individually. The correct sequence is to SSH into the worker node, run 'kubeadm upgrade node' to upgrade the kubelet configuration and static pod manifests, then upgrade the kubelet and kubectl binaries (typically via the package manager), and finally restart the kubelet to pick up the new version. This ensures the node runs the same Kubernetes version as the control plane.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Drain the node, then run 'kubeadm upgrade node' on the worker node.
Why it's wrong here
Draining is recommended before upgrading, but the immediate next step is to run kubeadm upgrade node on the worker node itself.
- ✓
SSH into the worker node and run 'kubeadm upgrade node', then upgrade kubelet and kubectl, then restart kubelet.
Why this is correct
This is the standard procedure for upgrading a worker node with kubeadm.
- ✗
Upgrade kubelet on the worker node using the package manager and restart kubelet.
Why it's wrong here
kubeadm must be upgraded first to ensure compatibility.
- ✗
Run 'kubeadm upgrade apply' on the worker node.
Why it's wrong here
kubeadm upgrade apply is only for the control plane, not worker nodes.
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Same concept, more angles
3 more ways this is tested on CKA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. During a cluster upgrade using kubeadm, after upgrading kubeadm on the node, which command upgrades the kubelet configuration?
hard- ✓ A.kubeadm upgrade node config --kubelet-version v1.29.0
- B.kubectl upgrade node kubelet
- C.kubeadm upgrade apply --kubelet-version v1.29.0
- D.systemctl restart kubelet
Why A: After upgrading kubeadm on the node, the correct command to upgrade the kubelet configuration is `kubeadm upgrade node config --kubelet-version v1.29.0`. This command updates the kubelet configuration file (typically `/var/lib/kubelet/config.yaml`) to match the target Kubernetes version, ensuring the kubelet can join the upgraded control plane. It is a specific subcommand of `kubeadm upgrade node` that handles only the kubelet configuration, not the kubelet binary itself.
Variation 2. You need to upgrade a Kubernetes cluster from v1.28 to v1.29 using kubeadm. After upgrading the control plane, what should you do on each worker node?
medium- A.kubeadm upgrade node config --kubelet-version v1.29.0
- B.kubectl delete node <node>; kubeadm upgrade node
- ✓ C.kubectl drain <node>; kubeadm upgrade node; kubectl uncordon <node>
- D.kubeadm upgrade node; kubectl uncordon <node>
Why C: The standard kubeadm upgrade workflow for worker nodes requires first draining the node to safely evict all pods, then running 'kubeadm upgrade node' to upgrade the kubelet and kube-proxy configuration, and finally uncordoning the node to make it schedulable again. This sequence ensures minimal disruption to workloads and follows the official Kubernetes upgrade documentation.
Variation 3. After upgrading the control plane using kubeadm, you need to update the kubelet configuration on the node. Which command should you run on the node?
medium- A.kubeadm upgrade apply
- B.kubectl upgrade node
- ✓ C.kubeadm upgrade node
- D.kubeadm upgrade plan
Why C: `kubeadm upgrade node` is the command used on worker nodes (or secondary control-plane nodes) after the primary control plane has been upgraded. It upgrades the kubelet configuration and other node-specific components to match the new cluster version, ensuring the node can rejoin the upgraded cluster.
Last reviewed: Jun 24, 2026
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