Ingress subdomain shows -- after creating an ibm-cloud kubernetes cluster

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06-10-2024

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"Subdomain Shows '--' after Creating an IBM Cloud Kubernetes Cluster: A Troubleshooting Guide"

Problem: After successfully creating an IBM Cloud Kubernetes cluster, you encounter a perplexing issue: your ingress subdomain shows "--" instead of the expected hostname. This frustrating situation prevents you from accessing your applications through the designated URL.

Scenario and Code:

Imagine this:

1. You've meticulously provisioned your IBM Cloud Kubernetes cluster with all the necessary configurations.
2. You've deployed your application, including an Ingress resource to manage external traffic.
3. Your Ingress resource is properly defined, using an ingress.kubernetes.io/hostname annotation to specify the desired subdomain.
4. You eagerly check your cluster's details, only to find your subdomain listed as "--".

Code Example:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
spec:
  rules:
  - host: myapp.mydomain.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80
  annotations:
    ingress.kubernetes.io/hostname: myapp.mydomain.com

Analysis and Troubleshooting:

The "--" subdomain indicates a problem with how IBM Cloud resolves your ingress hostname. This issue might stem from several factors:

• DNS Propagation Delay: After creating your cluster, it might take some time for the DNS changes to propagate across the internet. Wait for a reasonable period (usually a few minutes to an hour) before checking again.
• Incorrectly Configured DNS Records: Ensure you have the correct DNS records configured in your domain registrar's settings. The record type should be CNAME and point to your cluster's assigned hostname (found in the cluster's details).
• Ingress Controller Issues: Sometimes, the Ingress controller might have encountered a problem. Check the logs of your Ingress controller (usually kube-system namespace) for any error messages.
• IBM Cloud Service Outage: Though rare, there could be a temporary service outage affecting the Ingress functionality. Consult the IBM Cloud status page for any known issues.

Solutions:

1. Wait for DNS Propagation: Be patient! Give the DNS system time to update across all servers.
2. Verify DNS Records: Double-check your DNS records in your domain registrar's interface. Ensure the correct CNAME record points to your cluster's hostname.
3. Review Ingress Controller Logs: Access your Ingress controller logs for any errors. Look for clues about why the hostname isn't being resolved correctly.
4. Contact IBM Support: If you've exhausted other options, contact IBM Cloud support for assistance.

Additional Tips:

• Use a DNS Propagation Tool: Tools like https://whatsmydns.net/ can help monitor DNS propagation and identify any discrepancies.
• Cache Clearing: If you've recently made changes to your DNS settings, consider clearing your browser's cache and DNS cache to ensure you're seeing the most up-to-date information.
• Review IBM Cloud Documentation: Consult the official IBM Cloud Kubernetes documentation for detailed troubleshooting steps and best practices: https://cloud.ibm.com/docs/containers

Conclusion:

Resolving the "--" subdomain issue often involves patience and a systematic approach to troubleshooting. By carefully verifying DNS settings, checking for Ingress controller errors, and allowing sufficient time for DNS propagation, you can regain access to your applications through the desired hostname. Remember, if the issue persists, seeking help from IBM Cloud support can expedite the resolution process.