Fix: Kubernetes Ingress Returns 404 for All Paths

!Symptoms

• All requests to the ingress return 404 Not Found
• Ingress resource exists and has correct rules
• Backend services are running and healthy
• Direct service access via port-forward works fine

?Root Causes

• Ingress controller not installed or not running
• Ingress class annotation doesn't match the installed controller
• Backend service port doesn't match the ingress rule's service port
• Path type mismatch — using Exact when Prefix is needed
• IngressClass resource missing or not set as default

#Diagnosis Steps

1. 1Verify ingress controller is running: `kubectl get pods -n ingress-nginx`
2. 2Check ingress class: `kubectl get ingressclass` and compare with ingress annotation
3. 3Run `kubectl describe ingress <name>` — check rules and backend status
4. 4Test the service directly: `kubectl port-forward svc/<name> 8080:<port>`
5. 5Check ingress controller logs: `kubectl logs -n ingress-nginx <controller-pod>`

>Fix

1. 1Install an ingress controller: `helm install ingress-nginx ingress-nginx/ingress-nginx`
2. 2Set the correct ingressClassName in the ingress spec
3. 3Fix service port to match: compare `spec.rules[].http.paths[].backend.service.port`
4. 4Change pathType from Exact to Prefix if path matching is too strict
5. 5Create a default IngressClass: `ingressclass.kubernetes.io/is-default-class: true`

*Prevention

• Include ingress controller in cluster bootstrapping
• Validate ingress resources in CI with kubeval or kube-linter
• Use consistent ingressClassName across all ingress resources
• Add smoke tests that verify ingress routing after deployment
• Monitor ingress controller error rates in your observability stack

Related Error Messages