nginx ingress sub path redirection - nginx

Question

I have an ingress controller and ingress resource running with all /devops mapped to devopsservice in the backend. When I try to hit "http://hostname/devops" things work and I get a page (although without CSS and styles) with a set of hyperlinks for e.g one of them is "logs".
When I click on the "logs" hyperlink, it is redirecting me to http://hostname/logs whereas I need it to be http://hostname/devops/logs.
Any idea what I can do?
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
namespace: ingress-nginx
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/add-base-url : "true"
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /devops

Answer 1

Looks like your ingress is not serving anything /devops/*. Try adding another path /devops/* with the same backend. Basically this:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
namespace: ingress-nginx
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/add-base-url : "true"
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /devops/*
- backend:
serviceName: devops1
servicePort: 10311
path: /devops
Update: the above has been deprecated in favor of something like this:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: rewrite
namespace: default
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /devops(/|$)(.*)

Answer 2

If you access http://hostname/devops/logs directly from your browser, certainly you will get what you want. But since you click the hyperlink in the homepage, then you can only get http://hostname/logs, which will be certainly failed.
So, you need /logs backend configured in your ingress yaml to get it processed, and configure nginx.ingress.kubernetes.io/configuration-snippet to ensure /logs not get rewrote, like this:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
namespace: ingress-nginx
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/add-base-url : "true"
nginx.ingress.kubernetes.io/configuration-snippet: |
rewrite ^/logs /logs break;
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /logs
- backend:
serviceName: devops1
servicePort: 10311
path: /devops

Answer 3

I met the similar issue recently.
Assuming the "logs" hyperlink in your html uses a relative path, which means the hyperlink doesn't start with '/', then I think you can try to hit the page at http://hostname/devops/ instead of http://hostname/devops. (Note a / suffix in the first url.).
Then the "logs" hyperlink will be formed as http://hostname/devops/logs.
I think it's about how the browser identifies the 'base' url. With accessing 'http://hostname/devops/, if there is no 'base' tag in the html header, the 'base' url will be figured out to be http://hostname/devops; while with 'http://hostname/devops', the base url will be http://hostname.
If it's not the case, there is discussion at https://github.com/kubernetes/ingress-nginx/issues/4149. It's suggested a workaround to use the nginx directive subs_filter with a configuration-snippet to make the href attributes relative and also add the base tag in the html header.
The ingress used is as below,
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: rewrite
namespace: default
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /devops(/|$)(.*)

Answer 4

The nginx.ingress.kubernetes.io/x-forwarded-prefix annotation can be used for this purpose.
It adds x-forwarded-prefix header to http request with a value from this annotation. You can use it, if your backend support such header.
For example, Spring Boot application can handle it by using property:
server.forward-headers-strategy=framework
In your case ingress would look like the following:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
namespace: ingress-nginx
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/x-forwarded-prefix: /devops
spec:
rules:
- host: master1.dev.local
http:
paths:
- backend:
serviceName: devops1
servicePort: 10311
path: /devops
This solution has its downsides. It forces you to declare each service in separate ingress.