Introduction Port exhaustion is a pernicious, often misunderstood failure mode that can bring a high-traffic Nginx deployment to its knees. The symptoms are intermittent and confusing—spiky 5xx error rates, “Cannot assign requested address” in logs, and upstream timeouts—yet the root cause is usually simple: you ran out of usable ephemeral ports for outbound connections. In this article, we’ll explain what port exhaustion is and why Nginx is especially prone to it in reverse-proxy scenarios. We’ll cover how to diagnose it accurately, provide practical fixes at the Nginx and OS levels, and offer architectural strategies to prevent it from recurring. Whether you’re running bare metal, in containers, or behind a cloud NAT gateway, this guide will help you understand and solve Nginx port exhaustion. ...

Introduction Distributed systems run everything from streaming platforms to payment networks and logistics providers. Building them for production requires more than just connecting services—you need to understand failure modes, consistency models, data and network behavior, and how to operate systems reliably at scale. This article provides a high-level but comprehensive tour of the essential concepts you need in practice. It favors pragmatic guidance, proven patterns, and the “gotchas” teams hit in real-world environments. ...

Table of contents Introduction High-level overview: goals and building blocks Key distribution: hash slots and key hashing Cluster topology and the cluster bus Replication, failover and election protocol Client interaction: redirects and MOVED/ASK Rebalancing and resharding Failure detection and split-brain avoidance Performance and consistency trade-offs Practical tips for operating Redis Cluster Conclusion Resources Introduction Redis Cluster is Redis’s native distributed mode that provides horizontal scaling and high availability by partitioning the keyspace across multiple nodes and using master–replica groups for fault tolerance[1]. This article explains the cluster’s internal design and runtime behavior so you can understand how keys are routed, how nodes coordinate, how failover works, and what trade-offs Redis Cluster makes compared to single-node Redis[1][2]. ...

Introduction Downdetector stands as the world’s leading platform for real-time service status updates, tracking over 20,000 services across 49 countries and serving hundreds of millions of users monthly.[2] Unlike traditional monitoring tools that rely on internal metrics, Downdetector leverages crowdsourced user reports combined with signals from social media and web sources to detect outages.[2] This blog post dissects its internal workings, focusing on data collection, baseline calculations, aggregation algorithms, and incident thresholding—drawing directly from official methodology disclosures for an accurate, technical breakdown.[2] ...

Introduction Next.js has evolved into the de-facto full-stack React framework for building fast, scalable, and maintainable web applications. With the App Router, Server Components, Server Actions, Route Handlers, and first-class deployment on platforms like Vercel, you can go from concept to production quickly—without sacrificing performance or developer experience. This zero-to-hero guide will help you: Understand modern Next.js fundamentals (v14+ App Router). Learn practical patterns for data fetching, auth, performance, and testing. See code examples you can drop into your app. Follow a learning path from beginner to production. Build a portfolio with projects engineered to teach real-world skills. Dive deeper with curated, high-quality resources. If you’re ready to build production-grade apps with confidence, let’s get started. ...