Pod Network Latency Caused by Overloaded CNI Plugin

Pod network latency increased due to an overloaded CNI plugin.

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What Happened

Network latency increased across pods as the CNI plugin (Flannel) became overloaded with traffic, causing service degradation.

Diagnosis Steps

1Monitored CNI plugin performance and found high CPU usage due to excessive traffic handling.
2Verified that the nodes were not running out of resources, but the CNI plugin was overwhelmed.

Root Cause

CNI plugin was not optimized for the high volume of network traffic.

Fix/Workaround

• Switched to a more efficient CNI plugin (Calico) to handle the traffic load.
• Tuned the Calico settings to optimize performance under heavy load.

Lessons Learned

Always ensure that the CNI plugin is well-suited to the network load expected in production environments.

How to Avoid

1Test and benchmark CNI plugins before deploying in production.
2Regularly monitor the performance of the CNI plugin and adjust configurations as needed.