Linux & Kubernetes Practice Notes

This repository is a collection of concise, hands-on notes and scripts for practicing Linux administration fundamentals and preparing nodes for Kubernetes clusters in lab and real-world environments.

The focus is on understanding what happens before, during, and around Kubernetes setup—including OS preparation, networking, load balancing, and basic system operations.

Repository Structure

k8s/

Scripts and notes related to Kubernetes node and cluster preparation.

• k8s-preflight.sh
  Kubernetes node preflight validation script.
  Checks swap configuration, kernel modules, sysctl values, container runtime, kubelet status, Kubernetes binaries, and basic cluster connectivity.

• preflight-port-guard.sh
  Network and port safety checks to detect potential port conflicts before deploying Kubernetes components or load balancers.

• cleanup-kubeadm-init.md
  Notes for cleaning up a node after a failed or reset kubeadm init.

• master01-k8s-control-plane.md
  Control plane setup notes for a Kubernetes master node.

• lb01-haproxy-loadbalancer.md
  HAProxy-based load balancer setup for Kubernetes control plane access.

securezone2/load-balance/

Notes focused on Linux fundamentals and load balancer-related setup.

• servers-apache-nginx-setup.md
  Apache and Nginx installation and basic configuration notes.

• vip-setup-mainnode.md
  Virtual IP (VIP) configuration for main or load-balancer nodes.

• linux-basics.md
  File and directory operations, editing files, copy/move/delete, curl usage, and basic memory and disk concepts.

• linux-network-basics.md
  IP addressing, open ports, hostname configuration, DNS tools, /etc/hosts, and SSH port management.

• linux-package-management.md
  Package management using apt, yum, and dnf, including installing, upgrading, and removing packages.

• linux-log-and-system-info.md
  System and SSH logs, system time, disk and memory usage, DNS lookup tools, and network diagnostics.

Purpose

• Practice Linux system administration fundamentals
• Understand OS and network requirements for Kubernetes
• Prepare and validate nodes before kubeadm init / kubeadm join
• Maintain clear, reusable notes for labs, testing, and real environments