Introduction In system administration and development environments, it’s often necessary to test email sending functionality without relying on full applications or frameworks. Swaks (Swiss Army Knife for SMTP) is a powerful command-line tool that allows users to manually test SMTP servers and email delivery. This document outlines how to use… Continue Reading Sending Test Emails Using Swaks and SMTP2GO

From 21.4 MB to 1.89 MB: a practical look at optimising 3D characters for mobile applications. A 3D character can look perfect and still be far too expensive for a mobile app. We started with a 21.4 MB GLB asset containing a character, textures, skeleton, and 20 animations. After optimisation,… Continue Reading How We Shrunk a 3D Avatar by 91% Without Losing Visual Quality

Introduction SSH is commonly used to connect to Linux-based Amazon EC2 instances for server administration and troubleshooting. Sometimes an EC2 instance may be running normally. However, the SSH connection can still fail due to issues with the Security Group, Network ACL, route table, SSH service, key permissions, or instance configuration.… Continue Reading How to Troubleshoot SSH Connection Issues in AWS EC2

Introduction Every Kubernetes cluster secured with kubeadm relies on TLS certificates to protect communication between the control plane components. These certificates have a limited validity period and must be renewed before they expire. If certificate expiration is ignored, administrators may experience issues such as: Fortunately, kubeadm provides a straightforward method… Continue Reading How to Renew Kubernetes Certificates Using kubeadm (Step-by-Step Guide with Zero Planned Downtime)

Objective The objective of this module is to design and implement a secure and scalable authentication system for modern web applications. The architecture enables users to securely verify their identity, manage access sessions, and protect application resources through industry-standard authentication mechanisms while ensuring security, maintainability, and future scalability. Requirements Functional… Continue Reading Architecting a Secure Authentication System for Modern Web Applications

Introduction Metabase is a popular open-source business intelligence and data visualization platform that connects to multiple databases and allows users to create dashboards and reports. As a Metabase administrator, you may need to view all configured database connections for auditing, troubleshooting, or migration purposes. This article explains how to list… Continue Reading How to List Configured Databases in Metabase Using CLI/API?

Introduction Jenkins supports distributed builds by using agents (nodes). A Windows agent allows Jenkins to execute jobs on a Windows machine while the Jenkins controller manages the pipeline. This guide explains how to connect a Windows machine as a Jenkins agent using the Launch agent by connecting it to the… Continue Reading How to Connect a Windows Node (Agent) to Jenkins: A Complete Guide

Introduction Docker provides the docker commit command, which allows you to create a new image from the current state of an existing container. This is useful when you have made changes to a container—such as installing packages, updating configuration files, or modifying application data—and want to save those changes as… Continue Reading How to Convert a Docker Container into a Docker Image

Introduction Managing application configuration efficiently is essential in Kubernetes environments. Hardcoding configuration values such as database URLs, API endpoints, or application settings inside container images makes applications difficult to maintain and update. Kubernetes provides ConfigMaps, a native resource that allows you to separate configuration data from application code. This enables… Continue Reading How to Configure Kubernetes ConfigMaps: Managing Application Configuration

Objective The objective of this module is to design and implement a scalable Role-Based Access Control (RBAC) system for enterprise web applications. The architecture enables administrators to define roles, assign permissions, and enforce secure authorization across both frontend and backend services while maintaining flexibility for future role expansion. Requirements Functional… Continue Reading Architecting a Role-Based Access Control System for Enterprise Web Applications