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Scenario #163
Networking
K8s v1.20, Azure AKS
Network Partition Due to Incorrect Calico Configuration
Network partitioning due to incorrect Calico CNI configuration, resulting in pods being unable to communicate with each other.
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What Happened
Calico was misconfigured with an incorrect CIDR range, leading to network partitioning where some pods could not reach other pods in the same cluster.
Diagnosis Steps
- 1Verified pod connectivity using kubectl exec and confirmed network isolation between pods.
- 2Inspected Calico configuration and discovered the incorrect CIDR range in the calicoctl configuration.
Root Cause
Incorrect CIDR range in the Calico configuration caused pod networking issues.
Fix/Workaround
• Updated the Calico CIDR range configuration to match the cluster's networking plan.
• Restarted Calico pods to apply the new configuration and restore network connectivity.Lessons Learned
Ensure that network configurations, especially for CNI plugins, are thoroughly tested before deployment.
How to Avoid
- 1Use automated network validation tools to check for partitioning and misconfigurations.
- 2Regularly review and update CNI configuration as the cluster grows.