Google Kubernetes Engine ingress annotations

Question

I configure Ingress on google Kubernetes engine. I am new on ingress but as i understood ingress can serve different Loadbalancers and different LBs should be differently configured.

I have started with a simple ingress config on GKE :

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: basic-ingress

spec:
  rules:
  - http:
      paths:
      - path: /*
        backend:
          serviceName: web-np
          servicePort: 8080
      - path: /v2/keys
        backend:
          serviceName: etcd-np
          servicePort: 2379

And it works fine so I have 2 different NodePort services web-np and etcd-np . But now I need to extend this logic with some rewrite rules so that request that points to /service1 - will be redirected to the other service1-np service but before /service1/hello.html must be replaced to /hello.html. That's why I have the following questions:

How can I configure rewrite in ingress and if it is possible with default load balancer.
What is default load balancer on GKE.
Where can I find a list of all annotations to it. I have thought that the full list is on https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/ but there is a completly different list and there is no kubernetes.io/ingress.global-static-ip-name annotation that is widely used in google examples.

Dawid Kruk Dawid Kruk · Accepted Answer · 2020-05-29T13:14:02

Ingress - API object that manages external access to the services in a cluster, typically HTTP.

Ingress may provide load balancing, SSL termination and name-based virtual hosting.

Kubernetes.io: Ingress

Kubernetes can have multiple Ingress controllers. This controllers are different from each other. The Ingress controllers mentioned by you in this particular question are:

Ingress-GCE - a default Ingress resource for GKE cluster:
- Github.com: Kubernetes: Ingress GCE
Ingress-nginx - an alternative Ingress controller which can be deployed to your GKE cluster:
- Github.com: Kubernetes: Ingress-nginx

Ingress configuration you pasted will use the Ingress-GCE controller. If you want to switch to Ingress-nginx one, you will need to deploy it and set an annotation like:

kubernetes.io/ingress.class: "nginx"

How can I configure rewrite in ingress and if it is possible with default load balancer.

There is an ongoing feature request to support rewrites with Ingress-GCE here: Github.com: Ingress-GCE: Rewrite.

You can use Ingress-nginx to have support for rewrites. There is an official documentation about deploying it: Kubernetes.github.io: Ingress-nginx: Deploy

For more resources about rewrites you can use:

Kubernetes.github.io: Ingress nginx: Examples: Rewrite
Stackoverflow.com: Ingress nginx how to serve assests to application - this is an answer which shows an example on how to configure a playground for experimenting with rewrites

What is default load balancer on GKE.

If you create an Ingress resource with a default Ingress-GCE option you will create a L7 HTTP&HTTPS LoadBalancer.

If you create a service of type LoadBalancer in GKE you will create an L4 Network Load Balancer

If you deploy an Ingress-nginx controller in GKE cluster you will create a L4 Network Loadbalancer pointing to the Ingress-nginx controller which after that will route the traffic accordingly to your Ingress definition. If you are willing to use Ingress-nginx you will need to specify:

kubernetes.io/ingress.class: "nginx"

in your Ingress definition.

Please take a look on this article: Medium.com: Google Cloud: Kubernetes Nodeport vs Loadbalancer vs Ingress

Where can I find a list of all annotations to it. I have thought that the full list is on https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/ but there is a completly different list and there is no kubernetes.io/ingress.global-static-ip-name annotation that is widely used in google examples.

The link that you provided with annotations is specifically for Ingress-nginx. This annotations will not work with Ingress-GCE.

The annotations used in GCP examples are specific to Ingress-GCE.

You can create a Feature Request for a list of available annotations for Ingress-GCE on Issuetracker.google.com.

Google Kubernetes Engine ingress annotations

2 Answers