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

# Kubernetes CRDs

Custom resources (CRDs) are an efficient way of extending Kubernetes APIs, allowing us to make customized and declarative APIs. When we create a new CRD API, the `kube-apiserver` will create a new RESTful handler for each specified version. We'll demonstrate this shortly. The CRD can define either namespaced or cluster-scoped APIs, as specified in the field `spec.scope`.

Now, let's get started on how to use CRDs in Kubernetes.

## Create a custom resource

The development environment in which we can add and modify our programs is given below. We can click the "Run" button to initialize it.

In the `crd.yml` file, we define the CRD for the kind `Foo` **(line 31)** with the API group `pwk.educative.io` **(line 6)**. This `Foo` kind will be namespaced, because we specify `spec.scope` **(line 33)** as `Namespaced`. It could be `Cluster` if we want it cluster-scoped. Here, we start off with the version `v1alpha1` **(line 8)**. In this `Foo` kind, we've declared two fields, `deploymentName` **(line 19)** and `replicas` **(line 21)** in `spec`. We also set an integer range from `1` to `10` **(lines 23–24)** for `spec.replicas`. With this kind of structural schema, the `kube-apiserver` will help us validate all the `Foo` kind resources and reject those whose `spec.replicas` aren't in the range. In `status` **(lines 25–29)**, we have a field `availableReplicas` **(line 28–29)**, which is an integer as well.

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

How to Use Kubernetes CRDs

Kubernetes CRDs

Create a custom resource