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Scenario #13
Cluster Management
K8s v1.21 → v1.23 upgrade, kubeadm
Failed Cluster Upgrade Due to Unready Static Pods
Upgrade failed when static control plane pods weren’t ready due to invalid manifests.
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What Happened
During upgrade, etcd didn’t come up because its pod manifest had a typo. Kubelet never started etcd, causing control plane install to hang.
Diagnosis Steps
- 1Checked /etc/kubernetes/manifests/etcd.yaml for errors.
- 2Used journalctl -u kubelet to see static pod startup errors.
- 3Verified pod not running via crictl ps.
Root Cause
Human error editing the static pod manifest – invalid volumeMount path.
Fix/Workaround
• Fixed manifest.
• Restarted kubelet to load corrected pod.Lessons Learned
Static pods need strict validation.
How to Avoid
- 1Use YAML linter on static manifests.
- 2Backup manifests before upgrade.