Avoiding duplicate Ingress resources

Oct 13, 2025 by wbrum.org 61 views

Introduction

In the world of Kubernetes, serving web applications with rewrite targets under subpaths while appending slashes can be a complex task. The current implementation of Ingress resources in Kubernetes provides a way to achieve this using configuration snippets, but this approach is being phased out. In this article, we will explore the challenges of serving web applications with rewrite targets under subpaths while appending slashes and discuss possible solutions.

Current Implementation

The current implementation of Ingress resources in Kubernetes uses configuration snippets to achieve the desired behavior. The following is an example of an Ingress resource with an added rewrite rule to append a slash:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/use-regex: "true"
    nginx.ingress.kubernetes.io/rewrite-target: /$2
    nginx.ingress.kubernetes.io/configuration-snippet: |
      rewrite ^(/something)$ " $1/" permanent;
  name: rewrite
  namespace: default
spec:
  ingressClassName: nginx
  rules:
  - host: rewrite.bar.com
    http:
      paths:
      - path: /something(/|$)(.*)
        pathType: ImplementationSpecific
        backend:
          service:
            name: http-svc
            port:
              number: 80

This Ingress resource serves the web application under /something/, redirects /something to /something/, and rewrites the target to strip /something. However, this approach is being phased out, and we need to find alternative solutions.

Challenges

There are several challenges associated with serving web applications with rewrite targets under subpaths while appending slashes:

Redirecting third-party software: We cannot redirect third-party software in our own applications, so we need a solution that works for all paths.
Avoiding duplicate Ingress resources: We want to avoid declaring duplicate Ingress resources that redirect appending slashes.
Using ImplementationSpecific paths: We are fine with using ImplementationSpecific paths, but if we can somehow strip the prefix while using Prefix paths, that would be even better.

Possible Solutions

There are several possible solutions to this problem:

Using http://nginx.ingress.kubernetes.io/app-root: We can use the http://nginx.ingress.kubernetes.io/app-root annotation to serve the web application under a specific path. This approach works for all paths and does not require duplicate Ingress resources.
Using Prefix paths with autoredirect: We can use Prefix paths with autoredirect to serve the web application under a specific path. This approach also works for all paths and does not require duplicate Ingress resources.
Using a custom rewrite rule: We can use a custom rewrite rule to serve the web application under a specific path. This approach requires a custom Ingress resource and may not work for all paths.

Conclusion

Serving web applications with rewrite targets under subpaths while appending slashes can be a complex task. The current implementation of Ingress resources in Kubernetes uses configuration snippets, but this approach is being phased out. In this article, we have discussed the challenges associated with this problem and possible solutions. We have also explored the use of http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect as possible solutions. By using one of these approaches, we can serve web applications with rewrite targets under subpaths while appending slashes without declaring duplicate Ingress resources.

Future Work

In the future, we plan to explore the use of custom rewrite rules to serve web applications with rewrite targets under subpaths while appending slashes. We will also investigate the use of Prefix paths with autoredirect and http://nginx.ingress.kubernetes.io/app-root to determine which approach is the most efficient and scalable.

References

Kubernetes Ingress documentation
NGINX Ingress Controller documentation
Kubernetes Slack channel
Q&A: Serving Web Applications with Rewrite Targets Under Subpaths While Appending Slashes ====================================================================================

Introduction

In our previous article, we discussed the challenges of serving web applications with rewrite targets under subpaths while appending slashes. We also explored possible solutions, including using http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect. In this article, we will answer some frequently asked questions (FAQs) related to this topic.

Q: What is the difference between `http://nginx.ingress.kubernetes.io/app-root` and Prefix paths with autoredirect?

A: http://nginx.ingress.kubernetes.io/app-root is an annotation that allows you to serve a web application under a specific path. Prefix paths with autoredirect, on the other hand, use a specific path type to serve the web application and automatically redirect to the correct path.

Q: Can I use both `http://nginx.ingress.kubernetes.io/app-root` and Prefix paths with autoredirect in the same Ingress resource?

A: Yes, you can use both http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect in the same Ingress resource. However, you will need to configure them separately.

Q: How do I configure `http://nginx.ingress.kubernetes.io/app-root` in my Ingress resource?

A: To configure http://nginx.ingress.kubernetes.io/app-root in your Ingress resource, you will need to add the following annotation:

nginx.ingress.kubernetes.io/app-root: /path/to/app

Replace /path/to/app with the actual path to your web application.

Q: How do I configure Prefix paths with autoredirect in my Ingress resource?

A: To configure Prefix paths with autoredirect in your Ingress resource, you will need to add the following path type:

pathType: Prefix

You will also need to configure the path to your web application.

Q: Can I use a custom rewrite rule to serve my web application under a specific path?

A: Yes, you can use a custom rewrite rule to serve your web application under a specific path. However, this approach requires a custom Ingress resource and may not work for all paths.

Q: How do I configure a custom rewrite rule in my Ingress resource?

A: To configure a custom rewrite rule in your Ingress resource, you will need to add the following annotation:

nginx.ingress.kubernetes.io/rewrite-target: /path/to/app

Replace /path/to/app with the actual path to your web application.

Q: What are the benefits of using `http://nginx.ingress.kubernetes.io/app-root` and Prefix paths with autoredirect?

A: The benefits of using http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect include:

Simplified configuration
Improved scalability
Reduced complexity

Q: What are the limitations of using `http://nginx.ingress.kubernetes.io/app-root` and Prefix paths with autoredirect?

A: The limitations of using http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect include:

Limited flexibility
May not work for all paths

Conclusion

In this article, we have answered some frequently asked questions related to serving web applications with rewrite targets under subpaths while appending slashes. We have also discussed the benefits and limitations of using http://nginx.ingress.kubernetes.io/app-root and Prefix paths with autoredirect. By understanding these concepts, you can make informed decisions about how to configure your Ingress resources to meet your specific needs.