K8s: Custom Ingress Controller ~ Metac Idea

[AmitKumarDas]

https://www.doxsey.net/blog/how-to-build-a-custom-kubernetes-ingress-controller-in-go

[AmitKumarDas]

Kubernetes has support for mapping external domains to internal services via Ingress objects. The Ingress object I'm using looks like this:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: doxsey-www
spec:
  tls:
    - hosts:
        - "*.doxsey.net"
      secretName: doxsey-net-tls
  rules:
    - host: www.doxsey.net
      http:
        paths:
          - path: /
            backend:
              serviceName: doxsey-www
              servicePort: 9002

This manifest declares how incoming HTTP traffic should be routed to backend services:

• Any HTTP request to the www.doxsey.net domain, for any path will be routed to the doxsey-www service.
• If this is an HTTPS request, and the domain matches *.doxsey.net, the doxsey-net-tls certificate will be used for the request.

[AmitKumarDas]

Ingress Controllers

• In addition to the Ingress object, we have to install an Ingress Controller.

• This Controller is responsible for reading the ingress manifest rules and actually implementing the desired proxy behavior.

• In other words, an Ingress manifest is merely a declarative intent.

• The default ingress controller is the NGINX Ingress Controller, though there are many others.

• Although it was a fun exercise to implement my own, you should probably use one of these.

• There can be a lot of subtlety in handling all the edge cases, particularly when dealing with lots of services or rules, and those edge cases and bugs have probably been fixed in more widely used controllers.