DevOps: What is Kubernetes API Aggregation?

1# APIService registration
2apiVersion: apiregistration.k8s.io/v1
3kind: APIService
4metadata:
5  name: v1beta1.custom.example.com
6spec:
7  service:
8    name: custom-api-server
9    namespace: kube-system
10    port: 443
11  group: custom.example.com
12  version: v1beta1
13  insecureSkipTLSVerify: false
14  caBundle: <base64-ca-cert>
15  groupPriorityMinimum: 1000
16  versionPriority: 15
17---
18# Custom resource definition
19apiVersion: apiextensions.k8s.io/v1
20kind: CustomResourceDefinition
21metadata:
22  name: dashboards.custom.example.com
23spec:
24  group: custom.example.com
25  versions:
26  - name: v1beta1
27    served: true
28    storage: true
29    schema:
30      openAPIV3Schema:
31        type: object
32  scope: Namespaced
33  names:
34    plural: dashboards
35    singular: dashboard
36    kind: Dashboard
37    shortNames: ["dash"]
38  conversion:
39    strategy: Webhook
40    webhook:
41      clientConfig:
42        service:
43          name: conversion-webhook
44          namespace: kube-system
45        caBundle: <base64-ca-cert>

1# Commands
2kubectl get apiservices | grep custom
3kubectl describe apiservice v1beta1.custom.example.com
4
5# Access custom API
6kubectl get --raw /apis/custom.example.com/v1beta1/dashboards
7kubectl get --raw /apis/custom.example.com/v1beta1/namespaces/default/dashboards
8
9# Check availability
10kubectl get apiservice v1beta1.custom.example.com -o jsonpath='{.status.conditions}' | jq