Spot the debug scenario

Ingress returns 404

Ingress host or path rule does not match the incoming request.

Ingress returns 502/504

Service has no healthy endpoints or Pods are not Ready.

Ingress logs show requests but app logs show nothing

Service selector does not match Pod labels.

Service exists but kubectl get endpoints is empty

No Pods match the Service selector.

Pods are Running but traffic never arrives

Readiness probe is failing.

Internal curl to Pod IP works, Service DNS fails

Service port or targetPort mismatch.

Service DNS works but app errors

Connection reaching app but app misconfigured or crashing.

App logs show it's listening, but traffic fails

App bound to 127.0.0.1 instead of 0.0.0.0.

Multiple Pods exist but traffic hits only one

Session affinity or app-level sticky behavior.

Works locally with docker run but fails in Kubernetes

Missing Service or incorrect targetPort.

NodePort works but Ingress fails

Ingress configuration or controller issue.

Ingress resource looks correct but traffic fails

Ingress controller Pod not running or misconfigured.

LoadBalancer IP exists but no response

Cloud LB health checks failing.

Health checks failing but app is healthy

Readiness probe path or port is wrong.

kubectl port-forward works but Service doesn't

App works; Service wiring is broken.

Service works from one namespace but not another

Missing NetworkPolicy or DNS issue.

Traffic intermittently fails

Resource limits causing Pod restarts or throttling.

Requests hang indefinitely

App blocking or missing timeouts.

Only POST requests fail

Ingress or app method restrictions.

Works with IP but not hostname

DNS or TLS configuration issue.

HTTPS fails but HTTP works

TLS certificate or secret misconfigured.

Requests reach Pod but wrong backend responds

Service selector too broad.

Rolling deploy causes brief outages

Readiness probe delay too short.

Only one replica receives traffic

Other Pods failing readiness or crashing.

kubectl exec curl works but browser fails

CORS, headers, or Ingress config issue.

Service IP reachable but ClusterIP not

Route table or CNI issue.

Everything looks correct but nothing works

Check NetworkPolicy (silent traffic drop).

Pod restarts during traffic spikes

Resource limits too low.

Ingress returns 413

Request body size limit in Ingress controller.

Ingress returns 401/403

Auth middleware or ingress annotations.