Nginx Question posted in
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Why put a LoadBalancer Type of Service in front of the Nginx Ingress

I find some usecases of k8s in production which work with the Public Cloud will put a LoadBalancer type of Service in front of the Nginx Ingress. (You can find an example from the below yaml.)

As I known, ingress can be used to expose the internal servcie to the public, so what’s the point to put a loadbalancer in front of the ingress? Can I delete that service?

apiVersion: v1
kind: Service
metadata:
  annotations:
  labels:
    helm.sh/chart: ingress-nginx-3.27.0
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/version: 0.45.0
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: controller
    kubernetes.io/elb.class: union
  name: ingress-nginx-controller
  namespace: ingress-nginx
spec:
  type: LoadBalancer
  loadBalancerIP: xxx.xxx.xxx.xxx
  externalTrafficPolicy: Cluster
  ports:
    - name: http
      port: 80
      protocol: TCP
      targetPort: http
    - name: https
      port: 443
      protocol: TCP
      targetPort: https
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/component: controller
Tags:

2

Answers


  1. 0

    Because the Ingress Controller itself is, in this case, running inside a Pod so it needs to be exposed to the internet like anything else running in Pod. Some Ingress Controllers have the actual proxy running externally, like the AWS ALB one. But Nginx is just running inside the container like normal.

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  2. 0 
    ...so what's the point to put a loadbalancer in front of the ingress?

    This way allows you to take advantage of the cloud provider LB facilities (eg. multi-az etc), then with Ingress you can further control routing using path or name-based virtual host for services in the cluster.

    Can I delete that service?

    Ingress doesn’t do port mapping or pods selection, and you can’t resolve an Ingress name with DNS.

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