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Building a RAG Application with LangChain and Python: From Failure to Production

By IT From Zero February 28, 2026

Six months of hands-on experience building a RAG (Retrieval-Augmented Generation) system with LangChain and Python for an internal document lookup chatbot. From hallucination issues and context window limitations to a solution that actually works in production, with complete code examples.

Integrating ChatGPT API into Web Apps: Real-World Error Handling from Production

By IT From Zero February 28, 2026

Integrating the ChatGPT API into a real web app is more than just a few API calls — you'll hit rate limits, token overflow, and unstable latency the moment you deploy. This post cuts straight to the most common production failures and how to handle them properly from the start.

Installing Open WebUI: A Unified Web Interface for Managing Multiple AI Models

By IT From Zero February 28, 2026

A step-by-step guide to installing Open WebUI with Docker to manage multiple AI models — Ollama, GPT-4, Claude, and Gemini — from a single interface. Up and running in 5 minutes, with a full production deployment guide using Docker Compose and Nginx.

Docker

Install Portainer to Manage Docker via UI — No More Memorizing Commands, No More Mistakes

By IT From Zero February 28, 2026

Managing Docker via CLI every day is time-consuming and error-prone as your container count grows. This guide walks you through installing Portainer CE with Docker Compose v2, basic security configuration, and practical tips for more effective container management via the web interface.

Network

netstat vs ss: Analyzing Network Connections and Listening Ports on Linux

By IT From Zero February 28, 2026

A hands-on comparison of netstat and ss from real-world production server management — pros and cons of each tool, using ss for listening ports, filtering connections by IP, and debugging abnormal traffic in the middle of a live incident.

Ubuntu

Installing Free Let’s Encrypt SSL on Ubuntu with Certbot: From Real Errors to Auto-Renewal

By IT From Zero February 28, 2026

A cert expiring at 2am — a nightmare I've lived through. This guide covers everything: installing certbot via snap (the official method since 2021), fixing the most common errors, and setting up a deploy hook so nginx auto-reloads after renewal. Never get caught off guard by an expired cert again.

Database

Optimizing PostgreSQL Performance with PgBouncer: Connection Pooling in Production

By IT From Zero February 28, 2026

A guide to installing and configuring PgBouncer to address connection overhead in PostgreSQL. Real-world experience after 6 months in production: server connections reduced from 180 to 25, API response time improved from 800ms to under 300ms.

Docker

Docker Swarm Basics: A Complete Guide to Deploying Container Clusters from A to Z

By IT From Zero February 28, 2026

Docker Swarm frees you from the single-host trap: automatically distributes containers, scales with a single command, and performs zero-downtime rolling updates. This guide walks from a real-world problem to a fully working cluster setup, step by step.

Network

Setting Up a DNS Server with Bind9 on Ubuntu/Debian

By IT From Zero February 28, 2026

A step-by-step guide to setting up an internal DNS server with Bind9 on Ubuntu/Debian: installation, forward and reverse zone files, forwarder and ACL configuration, testing, and troubleshooting. Written from real-world experience managing an office network.

Database

Getting Started with Redis: Installation and Basic Usage — From 2 AM Production Crisis to Proficiency

By IT From Zero February 28, 2026

When a Django server starts timing out under heavy traffic, the culprit is often a database overwhelmed by repeated identical queries. This guide covers installing Redis on Linux, the essential commands you need to know, and how to integrate a cache layer into Python to immediately reduce database load.

A Guide to git push –force-with-lease: The Safer Force Push to Avoid Overwriting Teammates’ Code

A Guide to git merge-base: Finding the Common Ancestor Commit for Accurate Diffing in CI/CD

Ubuntu Server Security Auditing with Lynis: Vulnerability Scanning and Practical Hardening

Keyless Git Commit Signing with Gitsign and Sigstore: Modern Identity Verification

A Guide to Using OpenLLMetry and Traceloop for Monitoring and Tracing LLM Applications

A Guide to MySQL High Availability with Orchestrator: Automated Topology Discovery and Safe 2 AM Failover

How to Deploy Uptime Kuma with Docker Compose: Monitor Websites and Send Instant Telegram Alerts

How to Configure User Namespace Remapping (userns-remap) in Docker

Monitoring Pi-hole DNS Server with Prometheus and Grafana: Track DNS Query Traffic, Ad Blocking Rates, and Top Clients

Configuring systemd-journal-remote on Fedora Server: Centralized Logging over HTTPS mTLS

Building a RAG Application with LangChain and Python: From Failure to Production

Integrating ChatGPT API into Web Apps: Real-World Error Handling from Production

Installing Open WebUI: A Unified Web Interface for Managing Multiple AI Models

Install Portainer to Manage Docker via UI — No More Memorizing Commands, No More Mistakes

netstat vs ss: Analyzing Network Connections and Listening Ports on Linux

Installing Free Let’s Encrypt SSL on Ubuntu with Certbot: From Real Errors to Auto-Renewal

Optimizing PostgreSQL Performance with PgBouncer: Connection Pooling in Production

Docker Swarm Basics: A Complete Guide to Deploying Container Clusters from A to Z

Setting Up a DNS Server with Bind9 on Ubuntu/Debian

Getting Started with Redis: Installation and Basic Usage — From 2 AM Production Crisis to Proficiency