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Adding Cluster Ingress Options

When delivering a configurable application, ingress can be challenging as it is very cluster specific. Below is an example of a flexible ingress.yaml file designed to work in most Kubernetes clusters, including embedded clusters created with Replicated kURL.

Example​

The following example includes an Ingress resource with a single host based routing rule. The resource works in both existing clusters and embedded kURL clusters.

Config​

A config option enable_ingress has been provided to allow the end-user to choose whether or not to enable the Ingress resource. In some clusters a custom Ingress resource may be desired — when an ingress controller is not available, other means of exposing services may be preferred.

An annotations text area has been made available for the end-user to add additional annotations to the ingress. Here, cluster specific annotations can be added to support a variety of ingress controllers. For example, when using the ALB ingress controller in AWS, it is necessary to include the kubernetes.io/ingress.class: alb annotation on your Ingress resource.

apiVersion: kots.io/v1beta1
kind: Config
metadata:
  name: example-application
spec:
  groups:
    - name: ingress
      title: Ingress
      items:
        - name: enable_ingress
          type: bool
          title: Enable Kubernetes Ingress
          help_text: |
            When checked, deploy the provided Kubernetes Ingress resource.
          default: "1"
        - name: hostname
          type: text
          title: Hostname
          help_text: |
            Use this field to provide a hostname for your Example Application installation.
          required: true
          when: repl{{ ConfigOptionEquals "enable_ingress" "1" }}
        - name: allow_http
          type: bool
          title: Allow Unsecured Access through HTTP
          help_text: |
            Uncheck this box to disable HTTP traffic between the client and the load balancer.
          default: "1"
          when: repl{{ ConfigOptionEquals "enable_ingress" "1" }}
        - name: annotations
          type: textarea
          title: Annotations
          help_text: |
            Use this textarea to provide annotations specific to your ingress controller.
            For example, `kubernetes.io/ingress.class: alb` when using the ALB ingress controller.
          when: repl{{ ConfigOptionEquals "enable_ingress" "1" }}

Ingress​

For ingress, you must create two separate resources. The first of which will be deployed to existing cluster installations, while the second will only be deployed to an embedded cluster. Both of these resources are selectively excluded with the exclude annotation.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-application-ingress
  annotations:
    kots.io/exclude: '{{repl or (ConfigOptionEquals "enable_ingress" "1" | not) IsKurl }}'
    kubernetes.io/ingress.allow-http: '{{repl ConfigOptionEquals "allow_http" "1" }}'
    nginx.ingress.kubernetes.io/force-ssl-redirect: '{{repl ConfigOptionEquals "allow_http" "1" | not }}'
    kots.io/placeholder: repl{{ printf "'true'" }}repl{{ ConfigOption "annotations" | nindent 4 }}
spec:
  rules:
    - host: repl{{ or (ConfigOption "hostname") "~" }}
      http:
        paths:
          - path: /
            pathType: ImplementationSpecific
            backend:
              service:
                name: nginx
                port:
                  number: 80
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-application-ingress-embedded
  annotations:
    kots.io/exclude: '{{repl or (ConfigOptionEquals "enable_ingress" "1" | not) (not IsKurl) }}'
    kubernetes.io/ingress.allow-http: '{{repl ConfigOptionEquals "allow_http" "1" }}'
    nginx.ingress.kubernetes.io/force-ssl-redirect: '{{repl ConfigOptionEquals "allow_http" "1" | not }}'
    kots.io/placeholder: repl{{ printf "'true'" }}repl{{ ConfigOption "annotations" | nindent 4 }}
spec:
  tls:
    - hosts:
        - repl{{ ConfigOption "hostname" }}
      secretName: kotsadm-tls
  rules:
    - host: repl{{ ConfigOption "hostname" }}
      http:
        paths:
          - path: /
            pathType: ImplementationSpecific
            backend:
              service:
                name: nginx
                port:
                  number: 80