Kubernetes: Fixing the 404 Nginx Error in Docker Desktop's Ingress-Nginx v1.12.0-beta.0

Troubleshooting Ingress-Nginx 404 Errors in Kubernetes Deployments

Imagine you're in the middle of developing a Kubernetes application, everything is working smoothly, and then suddenly – after a simple page refresh – you’re hit with a frustrating 404 error. 🚧 This is a common problem many developers face, especially when deploying on platforms like Docker Desktop using tools like ingress-nginx.

In this case, the 404 error popped up while working with Ingress-Nginx v1.12.0-beta.0. It’s the kind of issue that feels unexpected and tricky to resolve, especially when it arises from a beta version update. And while Kubernetes and Docker provide powerful tools for microservices, occasional compatibility issues can emerge.

Restarting services, reapplying configurations, and even downgrading versions often feels like the right approach. Yet, as many have found, these steps don’t always pinpoint the root cause. Here, I’ll share my experience troubleshooting this error, especially since others facing this issue have found similar patterns.

The fix involved downgrading the Ingress-Nginx controller, but the root problem remains unresolved. Let's dive into how I approached this problem, what finally worked, and why it’s essential to understand potential compatibility challenges in beta releases. 🌐

Solving 404 Errors in Kubernetes with Ingress Nginx Configurations

The scripts provided are designed to tackle a specific issue: addressing unexpected 404 errors encountered when deploying applications with Ingress-Nginx in Kubernetes environments. This is a common hurdle, especially when using beta versions, such as Ingress-Nginx v1.12.0-beta.0 on Docker Desktop. The first script, written in YAML, configures an ingress resource with a rewrite target annotation, which helps route requests correctly by ensuring that paths match the intended backend services. By adding the nginx.ingress.kubernetes.io/rewrite-target annotation, the ingress controller can accurately rewrite paths. For instance, a request to “example.com/path” can be correctly forwarded to a service, even if the initial route isn't directly mapped. 🎯

The second script, a shell script, is a versatile debugging tool for checking and managing the ingress controller’s deployment and status. It begins by using the kubectl get pods command to see if all ingress-nginx components are up and running. If any issues are detected, the script can restart the ingress controller using kubectl rollout restart. Additionally, this script retrieves recent logs from the ingress controller, which can be essential for diagnosing 404 errors or routing issues. Reviewing logs can reveal specific misconfigurations or connectivity issues that are not always immediately apparent. These logs offer a window into any errors encountered by the ingress service, allowing for quicker identification of root causes.

In the third script, written in Node.js, an HTTP request is sent to validate if the ingress route properly forwards to the backend service. This script uses axios, a JavaScript library for making HTTP requests, to check if the configured ingress routes are accessible and returning the correct HTTP status. This approach simulates a client request to ensure that the route is working as expected from the end user’s perspective. For example, a successful response would confirm that the ingress is correctly configured and functional, while any error would signal a need for further troubleshooting. 🌐

The final YAML script addresses a potential fix by downgrading the Ingress-Nginx controller to a more stable version, specifically v1.11.0. The line specifying k8s.gcr.io/ingress-nginx/controller:v1.11.0 tells Kubernetes to pull and deploy the desired version. Downgrading can be effective when beta versions encounter unforeseen compatibility issues, as seen here with v1.12.0-beta.0. Many Kubernetes users have found stability by using a previous release, especially when testing experimental versions in development environments. This script ensures the rollback is applied correctly, aligning the deployment with a stable and supported ingress version to maintain smooth routing.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
    - host: example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: example-service
                port:
                  number: 80

#!/bin/bash
# Check if ingress-nginx controller is running correctly
kubectl get pods -n ingress-nginx
# Restart the ingress-nginx controller if any issues are found
kubectl rollout restart deployment/ingress-nginx-controller -n ingress-nginx
# Check for any potential errors in the logs
kubectl logs -l app.kubernetes.io/name=ingress-nginx -n ingress-nginx --tail 50
# Display ingress resource details
kubectl describe ingress
# Suggest removing and redeploying if issues persist
echo "If issues persist, delete ingress-nginx and reinstall the correct version."

const axios = require('axios');
// Endpoint URL to be tested
const testUrl = 'http://example.com/';
// Function to test endpoint response
async function testIngress() {
  try {
    const response = await axios.get(testUrl);
    if (response.status === 200) {
      console.log('Ingress is working. Received status 200.');
    } else {
      console.log('Unexpected status:', response.status);
    }
  } catch (error) {
    console.error('Error connecting to Ingress:', error.message);
  }
}
testIngress();

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
data:
  use-forwarded-headers: "true"
--- 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ingress-nginx-controller
  namespace: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: ingress-nginx
    spec:
      containers:
      - name: controller
        image: k8s.gcr.io/ingress-nginx/controller:v1.11.0

Understanding Compatibility Issues with Ingress-Nginx on Kubernetes

When working with Kubernetes and ingress-nginx, especially on platforms like Docker Desktop, version compatibility can sometimes lead to unexpected errors, like the infamous 404. Ingress controllers play a vital role in managing traffic and routing within a Kubernetes cluster, but new releases can bring both new features and potential compatibility issues. The v1.12.0-beta.0 release for Ingress-Nginx, for instance, brought changes that may not fully integrate with all Kubernetes environments yet, leading to these 404 errors when attempting to route traffic. This is particularly problematic when users, like in this case, face the error after an update or refresh, interrupting normal workflows. ⚙️

One important aspect to consider is the impact of annotations on ingress resources. Ingress annotations control how Nginx interprets the paths and routes, which can influence how requests are handled. Common annotations like “rewrite-target” adjust URL paths to ensure traffic is properly routed. However, new or changed annotations introduced in a beta release might not behave as expected in all environments. Checking for new configuration options or altered defaults between versions can save time, allowing developers to adjust paths or other settings to prevent 404 errors from appearing in the first place.

Finally, to ensure stable deployments, using stable versions of Ingress-Nginx in production while testing beta versions in development environments is wise. This approach reduces downtime caused by beta-related bugs and helps validate the setup under controlled conditions before a full release. Additionally, monitoring official release notes and known issues in beta versions can offer insights into potential compatibility challenges, helping teams preemptively avoid problems. In Kubernetes, managing this balance between experimentation and reliability is key, especially for complex applications reliant on precise ingress routing. 🌐