Cluster Autoscaler Preventing Scaling Due to Underutilized Nodes

The Cluster Autoscaler prevented scaling because nodes with low utilization were not being considered for scaling.

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What Happened

The Cluster Autoscaler was incorrectly preventing scaling because it did not consider nodes with low utilization, which were capable of hosting additional pods.

Diagnosis Steps

1Reviewed Cluster Autoscaler logs and found that it was incorrectly marking low-usage nodes as “under-utilized” and therefore not scaling the cluster.
2Observed that other parts of the cluster were under significant load but could not scale due to unavailable resources.

Root Cause

Cluster Autoscaler was not considering nodes with low resource utilization for scaling.

Fix/Workaround

• Reconfigured the Cluster Autoscaler to take node utilization more dynamically into account.
• Enabled aggressive scaling policies to allow under-utilized nodes to host additional workloads.

Lessons Learned

Cluster Autoscaler configuration should be fine-tuned to better handle all types of node utilization scenarios.

How to Avoid

1Regularly review Cluster Autoscaler settings and ensure they are optimized for dynamic scaling.
2Implement monitoring and alerting to detect autoscaling anomalies early.

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