Kubernetes Beginners Guide

1. Docker Overview

• Introduction to Docker
• Basics of containerization
• Docker images and containers
• Docker commands

2. Docker Orchestration

• Importance of orchestration
• Overview of Docker Compose
• Introduction to Kubernetes as an orchestration tool

3. Kubernetes Architecture

Cluster

A Cluster is a set of nodes (ranging from 1 to n) that work together to run containerized applications.

Master Node

• Watches and monitors the worker/slave nodes
• Responsible for the actual orchestration of worker/slave nodes

Components of Kubernetes

• API Server: Acts as the frontend for Kubernetes to interact with the cluster.
• etcd Service: A distributed and reliable key/value store for all data used to manage the cluster. Responsible for implementing logs within the cluster to prevent conflicts with the master.
• Scheduler: Distributes work across multiple nodes.
• Controllers: Handles node, container, and endpoint failures, bringing back failed or new resources as needed.
• Container Runtime: The underlying software used to run containers (e.g., Docker).
• Kubelet: An agent that runs on each node in the cluster to manage container operations.

Master and Worker Nodes

Master Nodes	Worker Nodes
API Server	Kubelet
etcd	Container Runtime
Controller
Scheduler

Worker Node / Minions

• Container Runtime (Docker): Runs the containers.

Managing Kubernetes with kubectl

kubectl is used to deploy and manage applications within a Kubernetes cluster.

Example Commands

kubectl run <image-name>       # Deploy an application
kubectl cluster-info           # Display cluster information
kubectl get nodes              # List all nodes in the cluster