Basic configuration

This document shows a basic Ingress resource definition for F5 NGINX Ingress Controller. It load balances requests for two services as part of a single application.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - cafe.example.com
    secretName: cafe-secret
  rules:
  - host: cafe.example.com
    http:
      paths:
      - path: /tea
        pathType: Prefix
        backend:
          service:
            name: tea-svc
            port:
              number: 80
      - path: /coffee
        pathType: Prefix
        backend:
          service:
            name: coffee-svc
            port:
              number: 80

Here is a breakdown of what this Ingress resource definition means:

• The metadata.name field defines the name of the resource cafe‑ingress.
• The spec.tls field sets up SSL/TLS termination:
  • The hosts field applies the certificate and key to the cafe.example.com host.
  • The secretName references a secret resource by its name, cafe‑secret. The secret must belong to the same namespace as the Ingress, of the type kubernetes.io/tls and contain keys named tls.crt and tls.key that hold the certificate and private key as described here. If the secret doesn’t exist or is invalid, NGINX will break any attempt to establish a TLS connection to the hosts to which the secret is applied.
• The spec.rules field defines a host with the domain name cafe.example.com.
• The paths field defines two path‑based rules:
  • The rule with the path /tea instructs NGINX to distribute the requests with the /tea URI among the pods of the tea service, which is deployed with the name tea‑svc in the cluster.
  • The rule with the path /coffee instructs NGINX to distribute the requests with the /coffee URI among the pods of the coffee service, which is deployed with the name coffee‑svc in the cluster.
  • Both rules instruct NGINX to distribute the requests to port 80 of the corresponding service (the servicePort field).

To learn more about the Ingress resource, view the official Kubernetes documentation for Ingress resources.

For complete instructions on deploying Ingress and Secret resources in the cluster, see the complete example in the GitHub repository.

New features available in Kubernetes 1.18

Starting from Kubernetes 1.18, you can use the following new features:

• The host field supports wildcard domain names, such as *.example.com.

• The path supports different matching rules with the new field pathType, which takes the following values: Prefix for prefix-based matching, Exact for exact matching and ImplementationSpecific, which is the default type and is the same as Prefix. For example:

  yaml

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    - path: /tea
      pathType: Prefix
      backend:
        serviceName: tea-svc
        servicePort: 80
    - path: /tea/green
      pathType: Exact
      backend:
          service:
            name: tea-svc
            port:
              number: 80
    - path: /coffee
      pathType: ImplementationSpecific
      backend:
          service:
            name: coffee-svc
            port:
              number: 80

• The ingressClassName field is now supported:

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    apiVersion: networking.k8s.io/v1
    kind: Ingress
    metadata:
      name: cafe-ingress
    spec:
      ingressClassName: nginx
      tls:
      - hosts:
        - cafe.example.com
        secretName: cafe-secret
      rules:
      - host: cafe.example.com
    . . .

  When using this field you need to create the IngressClass resource with the corresponding name. View the Create common resources section of the Installation with Manifests topic for more information.

Restrictions

NGINX Ingress Controller imposes the following restrictions on Ingress resources:

• When defining an Ingress resource, the host field is required.
• The host value needs to be unique among all Ingress and VirtualServer resources unless the Ingress resource is a mergeable minion. View the Host and Listener collisions topic for more information.
• The path field in spec.rules[].http.paths[] is required for Exact and Prefix pathTypes.
• The ImplementationSpecific pathType is treated as equivalent to Prefix pathType, with the exception that when this pathType is configured, the path field in spec.rules[].http.paths[] is not mandatory. path defaults to / if not set but the pathType is set to ImplementationSpecific.

Advanced configuration

NGINX Ingress Controller generates NGINX configuration by executing a template file that contains the configuration options.

These options are set with the Ingress resource and NGINX Ingress Controller’s ConfigMap.

The Ingress resource only allows you to use basic NGINX features: host and path-based routing and TLS termination.

For advanced configuration, you have two options:

• Annotations can be used to rewrite request URIs or inserting additional response headers.
• Snippets can be used to insert raw NGINX configuration, changing generated files.

Additionally, it is possible to customize the template, described in the Custom templates topic.