A quick look at the building blocks in simple terms for quick understanding.​

Review previous parts of this series for better understanding:

• Kuberenetes Overview
• Kubernetes Objects

This is third part of the Kubernetes series. In this part I will try to add more insights into the essential parts of Kubernetes. I will add more details on the topics in later in the series or there will separate posts as the topics needs.

Container

Container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another. The container runtime is responsible for starting and managing containers.

Kubernetes

Kubernetes is a powerful container orchestration system that can manage the deployment and operation of containerized applications across clusters of servers. In addition to coordinating container workloads, Kubernetes provides the infrastructure and tools necessary to maintain reliable network connectivity between your applications and services.

Node

A Node is physical or virtual machine. Every cluster must have at least one Master Node which controls cluster, and one or many Worker Node that hosts Pod.

Essential building blocks of the complicated system.​

Review Kuberenetes Overview

This is the second part of the Kubernetes series. In this part I will try to add more insights into Kubenetes Objects.

Kubernetes Objects

Kubernetes Objects are persistent entities in Kubernetes. All objects have unique names that allows idempotent creation and retrieval. These objects are stored in etcddatabase as a key-value pair. Objects can categorized as the Basic Objects which determines the deployed containerized application's workloads, their associated network and disk resources, and Higher Level Objects which are build upon the basic objects to provide additional functionality and convenience features to manage the workloads. Higher level objects have a long-running service-like lifecycle, except Jobs.

• Basic Objects: Pod, Service, Volume and Namespace
• Higher Level Objects: Replication Controllers, Replication Sets, Deployments, Stateful Sets, Daemon Sets Jobs and Cron Jobs

Every Kubernetes Object definition is a YAML file that contains at least the following items:

• apiVersion: The version of the Kubernetes API that the definition belongs to.
• kind: The Kubernetes object this file represents. For example, a pod or service.
• metadata: This contains the name of the object along with any labels that you may wish to apply to it.
• spec: This contains a specific configuration depending on the kind of object you are creating, such as the container image or the ports on which the container will be accessible from.