Note: This post was written a while back but sat in draft. I’ve published this now, but I’m not sure it’s relevant to the latest versions etc. so please bear this in mind.

You’ve implemented a service using ASP.NET deployed it to Kubernetes and all worked great, you then deploy a front end to use that service (as per the example in the Project Tye repo) again, all worked well. Whilst the Ingress mapped the path / to your front end services, the CSS an JS libs all worked fine, but then you change you Ingress route to (for example)

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress
  namespace: default
spec:
  rules:
    - http:
        paths:
          - path: /frontend
            pathType: Prefix
            backend:
              service: 
                name: frontend
                port: 
                  number: 80

In the above, the rule for the path /frontend will run the frontend service. All looks good so you navigate to http://your-server-ip/frontend and, wait a moment. The front end and backend services are working, i.e. you see some HTML and you see results from the backend service but Edge/Chrome/whatever reports 404 of bootstrap and your CSS.

The simplest solution, but with the downside that you are putting knowledge of the deployment route into your front end service is to just add the following to Startup.cs

app.UsePathBase("/frontend");

Obviously if you’re using tye or your own environment configuration, you might prefer to get the “/frontend” string from the environment configuration instead of hard coding.