GKE cluster upgrade fails when nodes timeout during upgrade, pod eviction fails, or control plane migration hangs. Clusters revert to original version or get stuck mid-upgrade due to insufficient capacity or blocking workloads.
This error occurs when GKE cannot complete the cluster upgrade process within the allowed timeframe. During upgrades, Google replaces nodes with new versions but must first evict pods and ensure cluster stability. If pods fail to evict, nodes hang during draining, or control plane components cannot migrate, the upgrade times out and rolls back. This leaves your cluster in an inconsistent state.
First diagnostic step
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Fourth diagnostic step
Additional notes and platform-specific considerations.
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Fifth diagnostic step