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Scenario #124
Networking
K8s v1.20, GKE
Service IP Conflict Due to CIDR Overlap
A service IP conflict occurred due to overlapping CIDR blocks, preventing correct routing of traffic to the service.
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What Happened
A new service was assigned an IP within a CIDR range already in use by another service, causing traffic to be routed incorrectly.
Diagnosis Steps
- 1Used kubectl get svc to check the assigned service IPs.
- 2Noticed the overlapping IP range between the two services.
Root Cause
Overlap in CIDR blocks for services in the same network.
Fix/Workaround
• Reconfigured the service CIDR range to avoid conflicts.
• Redeployed services with new IP assignments.Lessons Learned
Plan service CIDR allocations carefully to avoid conflicts.
How to Avoid
- 1Use a dedicated service CIDR block to ensure that IPs are allocated without overlap.
- 2Automate IP range checks before service creation.