Traefik V2: Why requests to subfolders are not routed properly? - kubernetes-ingress

Question

I try to migrate from Traefik V1 to V2 without the IngressRoute or Middleware.
my requests to /backend/something should be routed to the root of my backend service with /something.
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: demo-ingress
namespace: default
annotations:
kubernetes.io/ingress.class: traefik
traefik.ingress.kubernetes.io/redirect-regex: /backend$
traefik.ingress.kubernetes.io/redirect-replacement: /backend/
traefik.ingress.kubernetes.io/request-modifier: "ReplacePathRegex: ^/backend/(.*) /$1"
spec:
rules:
- host: demo.myapp.com
http:
paths:
- path: /
pathType: ImplementationSpecific
backend:
serviceName: frontend-app
servicePort: 80
- path: /backend # requests to /backend/something should end up in /something
pathType: ImplementationSpecific
backend:
service:
name: backend-api
port: http
How can I strip that?
At the moment requests to
/backend/something ends up in backend/something/ but should be /something
Thank you in advance
PS: is there a "tool" to monitor or test such requests?
This is a demo deployment I work with:
apiVersion: apps/v1
kind: Deployment
metadata:
name: frontend-app
namespace: default
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
resources:
requests:
cpu: 100m
memory: 100Mi
limits:
cpu: 100m
memory: 100Mi
ports:
- containerPort: 80
name: http
restartPolicy: Always
---
apiVersion: v1
kind: Service
metadata:
name: nginx
namespace: default
spec:
selector:
app: nginx
type: ClusterIP
sessionAffinity: None
sessionAffinityConfig:
clientIP:
timeoutSeconds: 10800
ports:
- name: http
protocol: TCP
port: 80
targetPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: backend-api
namespace: default
labels:
app: hello-world
spec:
selector:
matchLabels:
app: hello-world
replicas: 1
template:
metadata:
labels:
app: hello-world
spec:
containers:
- name: hello-world
image: rancher/hello-world:latest
resources: {}
ports:
- containerPort: 80
name: http
restartPolicy: Always
---
apiVersion: v1
kind: Service
metadata:
name: hello-world
namespace: default
spec:
selector:
app: hello-world
type: ClusterIP
sessionAffinity: None
sessionAffinityConfig:
clientIP:
timeoutSeconds: 10800
ports:
- name: http
protocol: TCP
port: 80
targetPort: 80

Answer 1

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: production-ingress
namespace: production
annotations:
kubernetes.io/ingress.class: traefik
traefik.ingress.kubernetes.io/router.entrypoints: web, websecure
# usage: namespace-middlewareName#kubernetescrdIsMandatory
traefik.ingress.kubernetes.io/router.middlewares: production-middleware-frontend#kubernetescrd,production-middleware-backend#kubernetescrd
traefik.ingress.kubernetes.io/router.tls: "true"
# cert-manager.io/cluster-issuer: letsencrypt-staging
spec:
rules:
- host: yourdomain.com
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: frontend
port:
number: 5000
- path: /backend
pathType: ImplementationSpecific
backend:
service:
name: backend
port:
number: 3000
tls:
- hosts:
- "yourdomain.com"
secretName: yourdomain-com-production-tls
---
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
name: middleware-backend
namespace: production
annotations:
kubernetes.io/ingress.class: traefik
spec:
stripPrefix:
prefixes:
- /backend
---
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
name: middleware-frontend
namespace: production
annotations:
kubernetes.io/ingress.class: traefik
spec:
stripPrefix:
prefixes:
- /