Can't setting CORS Traefik V2

Traefik Traefik v2
1

I'm trying to raise the version of Traefik I'm building on Kubernetes from v1 to v2.

I was able to update itself, but when I try to use the application after updating the Traefik version to v2, I get a CORS error.

I checked the documentation and found that CORS can be configured in the middleware configuration, so I configured it as follows.

trying to access https://backend.example.com from https://front.example.com

[http.middlewares]
  [http.middlewares.testHeader.headers]
    accessControlAllowMethods= ["GET", "OPTIONS", "PUT", "POST", "DELETE"]
    accessControlAllowOriginList = ["https://*.example.com"]
    accessControlMaxAge = 100
    addVaryHeader = true
  • ingress setting
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: example-app
  labels:
    app.kubernetes.io/name: example-app
  annotations:
    ingress.kubernetes.io/whitelist-x-forwarded-for: "true"
    ingress.kubernetes.io/protocol: https
    traefik.ingress.kubernetes.io/router.tls: "true"
    kubernetes.io/ingress.class: traefik
spec:
  rules:
    - host: backend.example.com
      http:
        paths:
          - path: /
            pathType: ImplementationSpecific
            backend:
              serviceName: example-app
              servicePort: 443

but this problem not sloved.

When I checked the error, I found that the preflight had failed.

has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

I would like to know if there is any part of the problem and if there are any other settings that need to be made.

Thank you.

2

Loading the configured middleware solves the preflight problem, but the CORS problem is still there.

3

Hi there @yuzujoe, I think the plugin traefik-plugin-cors might be able to help you :slight_smile:
See the pilot's plugin page.

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