Redirecting host to service path in kubernetes

Question

How do I redirect host to a service path in kubernetes?

I'm trying to try to match a host address to a service path, as an example, let's think i have an nginx pod servying to sites: site1 and site2. Let's think about a service called my-nginx-service which services my two sites as paths:

- my-nginx-service (178.123.55.37) - /site1 - /site2

There exists a way to map it to something like:

- host: site-one.mydomain.com http: paths: - backend: serviceName: nginx-service servicePort: 80 servicePath: /site2 - host: site-two.mydomain.com http: paths: - backend: serviceName: nginx-service servicePort: 80 servicePath: /site2

Kindly help me out

Answer 1

What you are trying to do is impossible, because services are unaware of host names. You might be able to reach what you want by modifying nginx configuration within the pod.

What you need to do is to add an ingress resource. Ingresses are aware of host names. They do load balancing between services. So, /site1 one would go to one service, and /site2 to the other one.

This is what the ingress should look like:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress
spec:
  rules:
  - host: site-one.mydomain.com
    http:
      paths:
      - backend:
          serviceName: nginx-service1
          servicePort: 80
  - host: site-two.mydomain.com
    http:
      paths:
      - backend:
          serviceName: nginx-service2
          servicePort: 80

As you can see site1 and site2 would be running in different deployments, with different services targeting them. Ingress, which is L7 Load Balancer would be able to check the host name and forward the request to the right service, which in the end would hit the right pod.

You can also add paths to each host, so site-one.mydomain.com/path1, site-one.mydomain.com/path2 and site-two.mydomain.com/path1 , would be forwarded to different services.

The Ingress yaml file would look like this:

apiVersion: extensions/v1beta1
kind: Ingress
 metadata:
  name: ingress
 spec:
  rules:
  - host: site-one.mydomain.com
    http:
      paths:
      - path: /path1
        backend:
          serviceName: nginx-service1
          servicePort: 80
      - path: /path2
        backend:
          serviceName: nginx-service2
          servicePort: 8080
      - path: /
        backend:
          serviceName: nginx-service3
          servicePort: 80
  - host: site-two.mydomain.com
    http:
      paths:
      - path: /path1
        backend:
          serviceName: nginx-service1
          servicePort: 80

Try this out and let me know if it worked for you!

Answer 2

Execute this command:

kubectl explain ingress.spec.rules.http.paths.backend:

...
FIELDS:
   serviceName  <string> -required-
     Specifies the name of the referenced service.

   servicePort  <string> -required-
     Specifies the port of the referenced service.
...

Specify your path in the following field: ingress.spec.rules.http.paths.path so that when that path is hit the request is routed using the Service specified at ingress.spec.rules.http.paths.backend.serviceName. If you're using nginx ingress the annotation nginx.ingress.kubernetes.io/rewrite-target: / can be used to redirect the request to /.