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Scenario #195
Networking
K8s v1.22, On-premise
Slow Pod Communication Due to Misconfigured MTU in Network Plugin
Pod-to-pod communication was slow due to an incorrect MTU setting in the network plugin.
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What Happened
The network plugin was configured with an MTU that did not match the underlying network's MTU, leading to packet fragmentation and slower communication between pods.
Diagnosis Steps
- 1Used ping to check latency between pods and observed unusually high latency.
- 2Inspected the network plugin’s MTU configuration and compared it with the host’s MTU, discovering a mismatch.
Root Cause
The MTU setting in the network plugin was too high, causing packet fragmentation and slow communication.
Fix/Workaround
• Corrected the MTU setting in the network plugin to match the host’s MTU.
• Restarted the affected pods to apply the changes.Lessons Learned
Ensure that MTU settings are aligned between the network plugin and the underlying network infrastructure.
How to Avoid
- 1Review and validate MTU settings when configuring network plugins.
- 2Use monitoring tools to detect network performance issues like fragmentation.