Author: Rahul

Docker has emerged as a game-changer for software developers, system administrators, and DevOps enthusiasts. Its containerization technology ensures that applications run uniformly across different platforms. In this article, we’ll guide you through the installation of the Docker Engine on several platforms. What is Docker Engine? Docker Engine is the core component of the Docker platform. It is responsible for building and running Docker containers. The Docker Engine comprises the server (long-running daemon process), REST API (specifies how to interact with the daemon) and CLI (command-line interface). Installation Guidelines 1. Docker Engine on Ubuntu: Follow these steps to install Docker Engine…

When managing Linux systems, especially Ubuntu and Debian, understanding where to find crontab logs is crucial for system administrators and developers. This article delves into the specifics of locating and interpreting cron logs in these popular distributions. Cron is a time-based job scheduler in Unix-like operating systems. Users employ this utility to schedule jobs (commands or scripts) to run periodically at fixed times, dates, or intervals. Crontab, the cron table, is a configuration file that specifies shell commands to run periodically on a given schedule. Default Cron Log Location In both Ubuntu and Debian, cron jobs and their outputs are…

Network Address Translation (NAT) with iptables is often used to allow systems on a private network to access external networks, like the internet, using a single public IP address. One of the most common uses of NAT is for masquerading, which allows all devices on a private network to appear as if they’re coming from a single device with a public IP. Here is a step-by-step tutorial for setting up masquerading with iptables: Prerequisites A Linux system with iptables installed. This system should have two network interfaces: one connected to the private network (e.g., eth1) and another to the public…

Docker volumes are an essential part of the containerized architecture, often used to persist data across container lifecycles. To safeguard against data loss, it’s vital to back up these volumes regularly. This article provides a shell script to automate the process of daily backups of Docker volumes, uploading them to AWS S3, and cleaning up old backups. Prerequisites Docker installed and running. AWS Command Line Interface (CLI) installed and configured with appropriate permissions. The `jq` tool installed to process JSON content (often used to parse Docker command outputs). Script Overview The script will do the following: Loop over each Docker…

Virtualization is a technique that enables the creation of several emulated environments or dedicated resources using one physical hardware system. This technology has become pivotal in data centers, cloud computing environments, and for many testing scenarios. While there are various virtualization techniques available, two of the most prominent ones are full virtualization and paravirtualization. Both have their own advantages, disadvantages, and use cases. Let’s delve deeper into their differences. Full Virtualization Definition: Full virtualization involves simulating a complete hardware layer on which an unmodified guest operating system can run, believing it’s running on an actual physical machine. How it works:…

In today’s IT environment, the quest for efficient and scalable software deployment strategies has led to the rise of two dominant technologies: virtualization and containerization. Both allow multiple operating systems and applications to run on a single physical server, but they do so in distinctly different ways. Here’s a deep dive into both technologies, comparing their advantages, disadvantages, and best-use cases. 1. What is Virtualization? Virtualization involves creating multiple virtual instances of a computer (virtual machines, or VMs) on a single physical server. Each VM has its operating system (OS), a full copy of an OS, and is allocated a…

FastAPI is a modern tool built with Python that helps you create backend APIs. To use the latest version of FastAPI, your computer needs to have at least version 3.8 of Python installed. Like many other frameworks, FastAPI can work with environment variables, which are a great way to manage settings separately from your code. This makes your application easier to manage and more secure. In this article, we’ll look at how to use .env files in your FastAPI application. These files are where you can store configuration settings, keeping them separate from your main application code. Why use a…

Apache’s mod_rewrite is one of the most powerful modules available for URL manipulation. With mod_rewrite, you can redirect URLs, rewrite URLs to make them cleaner, and much more. It is particularly useful for implementing SEO-friendly URL structures on your website. In this article, we will walk you through how to enable mod_rewrite in Apache on both Debian-based and RHEL-based systems. 1. Check if mod_rewrite is Already Enabled Before enabling mod_rewrite, it’s a good idea to check if it’s already active: apache2ctl -M | grep rewrite OR httpd -M | grep rewrite If you see `rewrite_module (shared)`, then mod_rewrite is already…

In today’s rapidly evolving technological landscape, companies and developers aim to deliver robust, scalable, and easily maintainable applications. Enter “microservices”, a term that has gained significant traction over the last few years. But what are they, and why have they become so popular? In this article, we’ll delve into the world of microservices, explore their key principles and benefits, and compare them with their predecessor, the monolithic architecture. What are microservices? Microservices, also known as the microservice architecture, refer to an architectural style that structures an application as a collection of loosely coupled, independently deployable services. Each service, or “microservice”,…

ZSH, short for the Z Shell, is one of the most popular Unix shells. It’s known for its rich features and enhancements over other shells like bash. One of the features it inherits from sh and enhances further is variable expansion. Variable expansion (or parameter expansion) is the mechanism by which the shell expands a variable to its value. This allows users to manipulate and use the value of a variable in various ways. 1. Basic Variable Expansion At its most basic, variable expansion in ZSH works just like it does in any other Bourne-style shell. name=”ZSH” echo $name #…