Kubernetes Ingress path based routing not working as expected - spring-boot

Question

I installed NGINX Ingress in kubernetes cluster. When i am trying to access the micro service end via Ingress Controller its not working as expected
I have deployed two spring boot application
Ingress Rules
Path 1 -> /customer
Path 2 -> /prac
When i am trying to access one of the service ex.
http://test.practice.com/prac/practice/getprac , it does not work
but when i try to access without Ingress path http://test.practice.com/practice/getprac, it works
I am not able to understand why with Ingress path its not working and same happens for other service
Micro service 1 (Port 9090)
apiVersion: apps/v1
kind: Deployment
metadata:
name: customer
namespace: practice
labels:
app: customer
spec:
replicas: 5
selector:
matchLabels:
app: customer
template:
metadata:
labels:
app: customer
spec:
imagePullSecrets:
- name: testkuldeepsecret
containers:
- name: customer
image: kuldeep99/customer:v1
ports:
- containerPort: 9090
hostPort: 9090
---
apiVersion: v1
kind: Service
metadata:
name: customer-service
namespace: practice
labels:
spec:
ports:
- port: 9090
targetPort: 9090
protocol: TCP
name: http
selector:
app: customer
Micro service 2 (port 8000)
apiVersion: apps/v1
kind: Deployment
metadata:
name: prac
namespace: practice
labels:
app: prac
spec:
replicas: 4
selector:
matchLabels:
app: prac
template:
metadata:
labels:
app: prac
spec:
imagePullSecrets:
- name: testkuldeepsecret
containers:
- name: prac
image: kuldeep99/practice:v1
ports:
- containerPort: 8000
hostPort: 8000
---
apiVersion: v1
kind: Service
metadata:
name: prac-service
namespace: practice
labels:
spec:
ports:
- port: 8000
targetPort: 8000
protocol: TCP
name: http
selector:
app: prac
Service (customer-service and prac-service)
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
customer-service ClusterIP 10.97.203.19 <none> 9090/TCP 39m
ngtest ClusterIP 10.98.74.149 <none> 80/TCP 21h
prac-service ClusterIP 10.96.164.210 <none> 8000/TCP 15m
some-mysql ClusterIP None <none> 3306/TCP 2d16h
Ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: practice-ingress
namespace: practice
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: practice.example.com
http:
paths:
- backend:
serviceName: customer-service
servicePort: 9090
path: /customer
- backend:
serviceName: prac-service
servicePort: 8000
path: /prac

Answer 1

You have installed this nginx ingress
nginx.ingress.kubernetes.io/rewrite-target: / annotation to work properly you need to install this nginx ingress.
Alternative way to solve this issue is to configure contextPath to /prac in the spring application

Answer 2

On top the discussion, i observed one thing. We should not confuse with
apiVersion: networking.k8s.io/v1
kind: Ingress
And
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
First ensure which Ingress controller we are using and based on that decide apiVersion. I'm using "ingress-nginx" (not "nginx-ingress"). This one supports "apiVersion: networking.k8s.io/v1beta1" and works charm as per "Arsene" comment.
This Ingress yaml file WORKS with "ingress-nginx" Ingress controller
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: k8-exercise-03-two-app-ingress
spec:
rules:
- host: ex03.k8.sb.two.app.ingress.com
http:
paths:
- backend:
serviceName: k8-excercise-01-app-service
servicePort: 8080
path: /one(/|$)(.*)
- backend:
serviceName: k8-exercise-03-ms-service
servicePort: 8081
path: /two(/|$)(.*)
But, this Ingress yaml file NOT WORKING with "ingress-nginx" Ingress controller
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: k8-exercise-03-two-app-ingress
annotations:
kubernetes.io/ingress.class: "nginx"
# nginx.ingress.kubernetes.io/use-regex: "true"
ingress.kubernetes.io/rewrite-target: /$2
spec:
# ingressClassName: nginx
rules:
#192.168.1.5 ex03.k8.sb.com is mapped in host file. 192.168.1.5 is Host machine IP
- host: ex03.k8.sb.two.app.ingress.com
http:
paths:
- backend:
service:
name: k8-excercise-01-app-service
port:
number: 8080
path: /one(/|$)(.*)
pathType: Prefix
- pathType: Prefix
path: /two(/|$)(.*)
backend:
service:
name: k8-exercise-03-ms-service
port:
number: 8081
I can access the Spring Boot API Calls as like:
For App-1:
http://ex03.k8.sb.two.app.ingress.com/one/
Result: App One - Root
http://ex03.k8.sb.two.app.ingress.com/one/one
Result: App One - One API
http://ex03.k8.sb.two.app.ingress.com/one/api/v1/hello
Result: App One - Hello API
App-2:
http://ex03.k8.sb.two.app.ingress.com/two/message/James%20Bond
Result: App Two- Hi James Bond API
Finally If any one knows how to change "apiVersion: networking.k8s.io/v1" yaml to support "ingress-nginx" Controller, will be appreciate. Thank you. Sorry for long content

Answer 3

I spend literally a day with this problem. The problem was simply the wrong nginx installed. I used helm found here to install nginx-ingress
Install it, please use helm version 3:
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update
helm install ingress-nginx ingress-nginx/ingress-nginx
Once run, in the logs you shall see a snippet that illustrates how your ingress should look like. In case you want to do the above, you can the annotation suggested above and henceforth, you can follow tutorials here to achieve more such as rewrite.
My cluster is deployed on GCP using GKE
when done, this is the output log:
NAME: ingress-nginx
LAST DEPLOYED: Sat Apr 24 07:56:11 2021
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The ingress-nginx controller has been installed.
It may take a few minutes for the LoadBalancer IP to be available.
You can watch the status by running 'kubectl --namespace default get services -o wide -w ingress-nginx-controller'
An example Ingress that makes use of the controller:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx
name: example
namespace: foo
spec:
rules:
- host: www.example.com
http:
paths:
- backend:
serviceName: exampleService
servicePort: 80
path: /
# This section is only required if TLS is to be enabled for the Ingress
tls:
- hosts:
- www.example.com
secretName: example-tls
If TLS is enabled for the Ingress, a Secret containing the certificate and key must also be provided:
apiVersion: v1
kind: Secret
metadata:
name: example-tls
namespace: foo
data:
tls.crt: <base64 encoded cert>
tls.key: <base64 encoded key>
type: kubernetes.io/tls
This is how it looks like now after installing it:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: example
# namespace: foo
spec:
rules:
- host: [your ip address].sslip.io
http:
paths:
- backend:
serviceName: registry-app-server
servicePort: 8761
path: /eureka/(.*)
- backend:
serviceName: api-gateway-server
servicePort: 7000
path: /api(/|$)(.*)
As you can see I am deploying spring micro-services using kubernetes(gke).
There are a lot of benefits of using nginx-ingress over built-in gke ingress, and it is more popular than its counterparts