Explore Kubernetes architecture, frameworks, and interfaces. Gain insights into deployment, scaling, and management of containerized applications. Discover extensibilities and get hands-on customizing Kubernetes.

k8s-go.tar.gz

k8s-go-v2

go-env-v2

Kubernetes is a popular open-source container orchestration system that automates the deployment, scaling, and management of containerized applications. This course is designed to provide a comprehensive understanding of Kubernetes and its programming concepts. You’ll dive deep into advanced topics of Kubernetes.

This course will cover topics such as Kubernetes architecture, frameworks, plugins, and interfaces. You’ll also learn the powerful extensibilities of Kubernetes and make full use of these built-in capabilities to build your customized Kubernetes.

This course is ideal for developers, DevOps engineers, and system administrators who want to learn how to master Kubernetes. By the end of the course, you’ll have a solid understanding of Kubernetes, its programming concepts, and be able to deploy, scale, and manage containerized customizations on Kubernetes. You will also get hands-on experience extending Kubernetes to meet your requirements.

Programming with Kubernetes

# Overview

The main reason for extending Kubernetes' core APIs would be those APIs not meeting our business requirements any more. Kubernetes has introduced two primary extension mechanisms to extend Kubernetes APIs--- CustomResourceDefinition (CRD) and the aggregated apiserver. They both provide RESTful APIs and work with `kubectl`. We can use `kubectl get` to get or list the resources, just like how we list Pods.

# What is the aggregated apiserver?

The **aggregated apiserver** (also known as the **custom apiserver**) is a standalone HTTP server that provides REST APIs. However, it works totally differently from CRD. In the aggregated apiserver, we can develop fully featured Kubernetes APIs. In straightforward terms, the aggregated apiserver works like another `kube-apiserver`. It cascades to the `kube-apiserver` to provide additional APIs that are not offered by the core Kubernetes APIs. This is why we use the word aggregated to describe it. The aggregated apiserver sits behind the `kube-apiserver`. This kind of arrangement is also called **API Aggregation (AA)**.

We can dynamically register our aggregated apiservers to the `kube-apiserver` by creating an `APIService` object below. The `kube-apiserver` determines where a request should be sent and knows how to contact it. With this object, we claim the URL path `/apis/<group>/<version>/...` in the `kube-apiserver`. If we manually create an object for registration, the aggregation layer will do nothing. Normally, we run our aggregated apiservers in Pods that run in our cluster. Moreover, we expose a service for aggregated apiservers, which will be referred to below the `APIService` object. To register multiple APIs with groups and versions, we just need to create multiple corresponding `APIService` objects. When we want to unregister our APIs, we just need to delete the corresponding `APIService` object from Kubernetes. We can register again anytime we want. Below is a sample YAML to register our APIs via the `APIService` object:

Get introduced to the aggregated apiserver in Kubernetes.

Before Getting Started

Kubernetes Architecture

Customizing AuthX

Dynamic Admission Control

Customizing Schedulers

Extending APIs with CustomResourceDefinition (CRD)

Extending APIs with Aggregated APIServer

Container Network Interface

Container Runtime Interface

Extend kubectl

How to Write Good Kubernetes Operators

Assessment of Programming with Kubernetes

Wrap Up

Introduction to Aggregated Apiserver