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Quick Tips for Troubleshooting Common Istio Issues in Kubernetes

Authors
  • avatar
    Name
    Alexander Arana Escobedo
    Twitter

Intro

I want to share some quick and practical tips that have helped me troubleshoot common Istio issues in the clusters I’ve been working with.

These tips are based on real errors I’ve encountered, simple checks that could save you a lot of time!

💡 Tips

Error: HTTPRoute/ROUTE_NAME namespace not specified

  • Verify that the gateway field in the HTTPRoute points to the correct Gateway in the correct namespace.

Error: HTTP/1.1 404 Not Found

  • Inspect the HTTPRoute for error messages with the kubectl get command:
kubectl get httproute <ROUTE_NAME> -n istio-system -o yaml
  • It could also be that you have specified the Gateway in the wrong namespace in your HTTPRoute YAML file.

Failure: Connection was reset

  • This often points to an issue with the TLS certificates. Ensure that your Kubernetes secret contains the full certificate chain (root, intermediates, and server cert).

Failure: Connection reset by peer

  • Check whether your Gateway resource actually exists.
  • Ensure your HTTPRoute is pointing to the correct namespace where your Gateway is located.

Error: istio error 404 NR route_not_found

  • This usually means Istio cannot find a route for the request. Verify that the correct Istio credentials (secrets) are located in the correct namespace (often istio-ingress or aks-istio-ingress).

HTTP 400

  • This can often indicate a misconfiguration in your VirtualService.

HTTP 500

  • Ensure you’re using the correct certificate or trusted CA during your requests.

⚠️ Important Note:

  • If you’ve updated or changed the Kubernetes Istio TLS secrets, remember to restart your ingress gateway pods. These are often located in the istio-ingress or aks-istio-ingress namespace. You can do this with the command below:
kubectl rollout restart deployment <INGRESS_GATEWAY_DEPLOYMENT_NAME> -n istio-ingress

🚀 Bonus tips!

  • Fetch the external IP of the Istio Gateway:
INGRESS_HOST_INTERNAL=$(kubectl -n istio-system  get service istio-ingress-gateway -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
  • Fetch the external port for the Istio Gateway:
INGRESS_PORT_INTERNAL=$(kubectl -n istio-system get service istio-ingress-gateway -o jsonpath='{.spec.ports[?(@.name=="http2")].port}')
  • Run curl to confirm if your Istio setup is working correctly:
# For testing the HTTP connection:
curl -s "http://$INGRESS_HOST_INTERNAL:$INGRESS_PORT_INTERNAL" -v

# For testing the HTTPS connection:
curl -s "https://$INGRESS_HOST_INTERNAL:$INGRESS_PORT_INTERNAL" -v

I hope these quick tips help you troubleshoot Istio issues a little faster! If you’ve run into other tricky Istio errors or have additional tips to share, feel free to reach out — happy to connect! 🙏

Alexander Arana.E

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