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Scenario #73
Cluster Management
K8s v1.21, AWS EKS

Service Discovery Issues Due to DNS Resolution Failures

Services could not discover each other due to DNS resolution failures, affecting internal communication.

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What Happened

Pods were unable to resolve internal service names due to DNS failures, leading to broken inter-service communication.

Diagnosis Steps
  • 1Checked DNS logs and found dnsmasq errors.
  • 2Investigated CoreDNS logs and found insufficient resources allocated to the DNS pods.
Root Cause

CoreDNS pods were running out of resources (CPU/memory), causing DNS resolution failures.

Fix/Workaround
• Increased resource limits for the CoreDNS pods.
• Restarted CoreDNS pods to apply the new resource settings.
Lessons Learned

Ensure that CoreDNS has enough resources to handle DNS requests efficiently.

How to Avoid
  • 1Monitor CoreDNS pod resource usage.
  • 2Allocate adequate resources based on cluster size and workload.
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