Kubernetes Ingress - how to access my service on my computer?-CodePudding

I have the following template, with a deployment, a service and an Ingress. I ran minikube addons enable ingress locally to add an ingress controller before.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: fastapi
  labels:
    app: fastapi
spec:
  replicas: 1
  selector:
    matchLabels:
      app: fastapi
  template:
    metadata:
      labels:
        app: fastapi
    spec:
      containers:
        - name: fastapi
          image: datamastery/fastapi
          ports:
            - containerPort: 3000
---
apiVersion: v1
kind: Service
metadata:
  name: fastapi-service
spec:
  selector:
    app: fastapi
  type: LoadBalancer
  ports:
    - protocol: TCP
      port: 5000
      targetPort: 3000
      nodePort: 30002
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: dashboard-ingress
  namespace: kubernetes-dashboard
  annotations:
    kubernetes.io/ingress.class: "nginx"
spec:
  rules:
    - host: datamastery.com
      http:
        paths:
          - path: /
            pathType: Exact
            backend:
              service:
                name: fastapi-service
                port:
                  number: 3000

When I run kubectl get servicesI get:
fastapi-service LoadBalancer 10.108.5.228 <pending> 5000:30002/TCP 5d22h

I my etc/hosts/ file I added the following:

10.108.5.228 datamastery.com

Normally I would expect now to be able to open my service in the browser, but nothing happens. What did I do wrong? Did I miss something in the template? Is the IP wrong? Something in the hosts file?

Thank you!

CodePudding user response：

fastapi-service LoadBalancer 10.108.5.228 5000:30002/TCP 5d22h

10.108.5.228 is an address within your SDN. Only members of your SDN can reach this address, it is unlikely your workstation would have a route sending this trafic to one of your Kubernetes nodes.

<pending> means your cluster is not integrated with a cloud provider with LoadBalancer capabilities. When in doubt: you should use ClusterIP as your service type. LoadBalancer only makes sense in specific cases. While setting a nodePort as you did is also not required (would make sense with a NodePort service, which is as well useful in few use cases, though should not be used otherwise).

You did create an Ingress. If you have an Ingress Controller, you want to connect to that ip/port. The Host header would tell your ingress controller where to route this, within your SDN.

CodePudding user response：

I believe what you are doing here is trying to combine two different things.

NodePort is only sufficient if you have only one node OR you really control where your service pods getting deployed. Otherwise it is not suitable to use the node IP to access services.

To overcome this issue we usually use ingress as a service proxy. Incoming traffic will be routed to the correct service pods depending on the URL and port. Ingress also manages the SSL termination. So basically this is your first "load balancer" as ingress assigned traffic to services across nodes and pods.

In production environment you deploy the ingress controller with the type: Loadbalancer in the kube-system namespace, example for Nginx-ingress:

apiVersion: v1
kind: Service
metadata:
  name: nginx-ingress
  namespace: kube-system
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: LoadBalancer
  ports:
    - port: 80
      name: http
      targetPort: 80
    - port: 443
      name: https
      targetPort: 443
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

This would spin up a cloud load balancer of your provider and link it to the ingress service in your cluster. So basically now you would have a real load balancer in place balancing traffic between your nodes and ingress routes them to your services and services to your pods.

Back to your question:

In your config files you try to spin up a service with the type: LoadBalancer. This would skip the ingress part and spin up a second cloud load balancer from your provider dedicated for this single service.

You have to remove the type (and nodePort) to use default ClusterIP for your service.

apiVersion: v1
kind: Service
metadata:
  name: fastapi-service
spec:
  selector:
    app: fastapi
  ports:
    - protocol: TCP
      port: 3000
      targetPort: 3000

In addition you have mentioned a wrong port. Your ingress object points on port 3000. You Service object on port 5000. So we also change this.

With this config your traffic on the FQDN is routed to ingress, to ClusterIP service on port 3000 to your pods.