(LFS258) Lab 11.2: Was anyone successful in creating a Path based ingress? I failed to make it work.

a.zoubi · August 2022

Hi all, I've finished lab 11.2 successfully, and I understand that it illustrates name-based virtual hosting ingress. Then I referred to the documentation https://kubernetes.io/docs/concepts/services-networking/ingress/ and tried the Path based ingresses, but non worked for me. Am I missing something, please?

Here are my services:

ahmad@k8s-master:~$ kc get svc
NAME                                           TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
kubernetes                                     ClusterIP      10.96.0.1        <none>        443/TCP                      7d1h
myingress-ingress-nginx-controller             LoadBalancer   10.107.16.253    <pending>     80:31213/TCP,443:32356/TCP   51m
myingress-ingress-nginx-controller-admission   ClusterIP      10.106.108.230   <none>        443/TCP                      51m
web-one                                        ClusterIP      10.100.215.198   <none>        80/TCP                       54m
web-two                                        ClusterIP      10.101.173.35    <none>        80/TCP                       56m
ahmad@k8s-master:~$ curl 10.100.215.198
...
<body>
<h1>Welcome to Web One!</h1>
...
ahmad@k8s-master:~$ curl 10.101.173.35
...
<h1>Welcome to Web Two!</h1>
...
ahmad@k8s-master:~$

Here is my ingress (first rule has a specific host with specific path | second rule has only a specific host):

ahmad@k8s-master:~$ kc get ingress ingress-test -o yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
  creationTimestamp: "2022-08-13T22:19:51Z"
  generation: 5
  name: ingress-test
  namespace: default
  resourceVersion: "44392"
  uid: d055dd79-1da7-44bf-bcd0-6058a5955452
spec:
  rules:
  - host: www.k8s-worker.com
    http:
      paths:
      - backend:
          service:
            name: web-two
            port:
              number: 80
        path: /web-two
        pathType: ImplementationSpecific
  - host: www.k8s-master.com
    http:
      paths:
      - backend:
          service:
            name: web-one
            port:
              number: 80
        path: /
        pathType: ImplementationSpecific
status:
  loadBalancer: {}

Testing the second rule to service web-one is successfull:

ahmad@k8s-master:~$ curl -H "Host: www.k8s-master.com" http://10.107.16.253
...
<h1>Welcome to Web One!</h1>
...

Testing the first rule to service web-two fails (I am not sure how to specify the path in the curl command, I searched a lot and couldn't find a working solution):

ahmad@k8s-master:~$ curl -H "Host: www.k8s-worker.com" http://10.107.16.253/web-two
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.23.1</center>
</body>
</html>

oleksazhel · August 2022

@a.zoubi It is correct behaviour because nothings lives inside nginx on non-root path, that's why page was not found. Seems in kubernetes doc it was not mentioned, may be because they believe it is obvious) I found another explanation for you in this article https://docs.giantswarm.io/advanced/ingress/configuration/

This is quote from it:

Note: Your applications need to be capable of running on a non-root path either by default or by setting the base path in their configuration.

a.zoubi · August 2022

Thanks for the answer @oleksazhel , yes it now makes sense.
I think I misunderstood the whole concept when I saw the graph in https://kubernetes.io/docs/concepts/services-networking/ingress/#simple-fanout , I thought that based on the path in the url, ingress will redirect the request to a new service to the Root Dir of that service. What you are saying, and what makes sense, is that the request will be redirected to a new service and the path will be forwarded to the service as well.

chrispokorni · August 2022

Hi @a.zoubi,

I noticed in both cases, the Kubernetes documentation and the article referenced, the pathType is set to Prefix for multiple hosts. The lab guide uses the ImplementationSpecific pathType which may not be suited for this use case.

Could you change the pathType values and test again?

Regards,
-Chris

a.zoubi · August 2022

@chrispokorni said:
Hi @a.zoubi,

I noticed in both cases, the Kubernetes documentation and the article referenced, the pathType is set to Prefix for multiple hosts. The lab guide uses the ImplementationSpecific pathType which may not be suited for this use case.

Could you change the pathType values and test again?

Regards,
-Chris

Thanks for the reply. Yes here is the result.

ahmad@k8s-master:~$ kc delete ingress ingress-test
 
ahmad@k8s-master:~$ kc create -f ingress.yaml
 
ahmad@k8s-master:~$ kc get ingress ingress-test -o yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
...
spec:
  rules:
  - host: www.k8s-worker.com
    http:
      paths:
      - backend:
          service:
            name: web-two
            port:
              number: 80
        path: /web-two
        pathType: Prefix
  - host: www.k8s-master.com
    http:
      paths:
      - backend:
          service:
            name: web-one
            port:
              number: 80
        path: /web-one
        pathType: Prefix
...
 
ahmad@k8s-master:~$ curl -H "Host: www.k8s-master.com" http://10.107.16.253/web-one
...
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.23.1</center>
...
ahmad@k8s-master:~$ curl -H "Host: www.k8s-master.com" http://10.107.16.253/web-two
...
<center><h1>404 Not Found</h1></center>
<hr><center>nginx</center>
...

Is the curl request correct? Or shall I send it in another way?

a.zoubi · August 2022

The answer by @oleksazhel is correct. I created two new nginx pods and created files in the web RootDirectory to serve new paths, and the ingress now works well.

The ingress created as above, and below are the test results.

ahmad@k8s-master:~$ kc get svc
NAME                                           TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
kubernetes                                     ClusterIP      10.96.0.1        <none>        443/TCP                      9d
myingress-ingress-nginx-controller             LoadBalancer   10.107.16.253    <pending>     80:31213/TCP,443:32356/TCP   2d1h
myingress-ingress-nginx-controller-admission   ClusterIP      10.106.108.230   <none>        443/TCP                      2d1h
web-one                                        ClusterIP      10.106.167.151   <none>        80/TCP                       6m11s
web-two                                        ClusterIP      10.105.17.0      <none>        80/TCP                       6m9s

Now curl to specific service requesting the path:

ahmad@k8s-master:~$ curl 10.106.167.151/web-one
Hello, this is WEB ONE!
ahmad@k8s-master:~$ curl 10.105.17.0/web-two
Hello, this is WEB TWO!

Now curl to the ingress service ip adding host header and requesting the path:

ahmad@k8s-master:~$ curl -H "Host: www.k8s-master.com" 10.107.16.253/web-one
Hello, this is WEB ONE!
ahmad@k8s-master:~$ curl -H "Host: www.k8s-worker.com" 10.107.16.253/web-two
Hello, this is WEB TWO!
ahmad@k8s-master:~$

And it worked with pathType set to "Exact", "Prefix" or "ImplementationSpecific". It doesn't matter.

Also, you can remove the following line(s) from the ingress yaml file to make the rule based off of paths only:

...
- host: www.k8s-worker.com
...
- host: www.k8s-master.com
...

(LFS258) Lab 11.2: Was anyone successful in creating a Path based ingress? I failed to make it work.

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