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Exposing Services

1. via Ingress

In this example, we will deploy a simple nginx webserver deployment and make it accessible via ingress. Therefore, we have to create the cluster in a way, that the internal port 80 (where the traefik ingress controller is listening on) is exposed on the host system.

  1. Create a cluster, mapping the ingress port 80 to localhost:8081

    k3d cluster create --api-port 6550 -p 8081:[email protected] --agents 2

    Good to know

    • --api-port 6550 is not required for the example to work. It’s used to have k3s‘s API-Server listening on port 6550 with that port mapped to the host system.
    • the port-mapping construct 8081:[email protected] means
      • map port 8081 from the host to port 80 on the container which matches the nodefilter loadbalancer
    • the loadbalancer nodefilter matches only the serverlb that’s deployed in front of a cluster’s server nodes
      • all ports exposed on the serverlb will be proxied to the same ports on all server nodes in the cluster
  2. Get the kubeconfig file

    export KUBECONFIG="$(k3d kubeconfig write k3s-default)"

  3. Create a nginx deployment

    kubectl create deployment nginx --image=nginx

  4. Create a ClusterIP service for it

    kubectl create service clusterip nginx --tcp=80:80

  5. Create an ingress object for it with kubectl apply -f Note: k3s deploys traefik as the default ingress controller

    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      name: nginx
      annotations:
        ingress.kubernetes.io/ssl-redirect: "false"
    spec:
      rules:
      - http:
          paths:
          - path: /
            backend:
              serviceName: nginx
              servicePort: 80
    
  6. Curl it via localhost

    curl localhost:8081/

2. via NodePort

  1. Create a cluster, mapping the port 30080 from agent-0 to localhost:8082

    k3d cluster create mycluster -p 8082:[email protected][0] --agents 2

    • Note: Kubernetes’ default NodePort range is 30000-32767

… (Steps 2 and 3 like above) …

  1. Create a NodePort service for it with kubectl apply -f

    apiVersion: v1
    kind: Service
    metadata:
      labels:
        app: nginx
      name: nginx
    spec:
      ports:
      - name: 80-80
        nodePort: 30080
        port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx
      type: NodePort
    
  2. Curl it via localhost

    curl localhost:8082/


Last update: August 5, 2020