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Raymond Ops

Linux ops automation, cloud-native, Kubernetes, SRE, DevOps, Python, Golang and related tech discussions.

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Latest from Raymond Ops

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Raymond Ops

Aug 8, 2026 · Operations

Mastering K8s Troubleshooting: Common Production Issues and Essential Commands

This guide walks you through the most frequent Kubernetes production problems—from pod failures like CrashLoopBackOff and ImagePullBackOff to node NotReady states, service DNS errors, storage PVC issues, RBAC permissions, and scheduling conflicts—providing step‑by‑step diagnostic commands, concrete examples, and practical remediation strategies to keep your clusters stable and your services running.

KubernetesNodeProduction

0 likes · 51 min read

Mastering K8s Troubleshooting: Common Production Issues and Essential Commands

Raymond Ops

Aug 8, 2026 · Operations

A Complete Walkthrough of Investigating High Server Load in Production

This article narrates a step‑by‑step investigation of a sudden CPU load spike on a 24‑core e‑commerce web server, revealing an I/O bottleneck caused by misconfigured log rotation and excessive debug logging, and outlines the diagnostic commands, root‑cause analysis, immediate remediation, and long‑term fixes.

I/O BottleneckLinuxLoad Average

0 likes · 19 min read

A Complete Walkthrough of Investigating High Server Load in Production

Raymond Ops

Aug 6, 2026 · Databases

Diagnosing and Eliminating MySQL Deadlocks in Production

This article explains how MySQL deadlocks arise, details the four necessary conditions, compares lock types, shows how to enable detailed deadlock logging, query lock metadata, interpret logs, and provides practical code‑level and configuration strategies to prevent and resolve common deadlock scenarios in production environments.

DeadlockInnoDBMySQL

0 likes · 20 min read

Diagnosing and Eliminating MySQL Deadlocks in Production

Raymond Ops

Aug 6, 2026 · Information Security

How to Harden SSH Without Locking Yourself Out

This guide explains why the default SSH configuration is insecure, walks through protocol basics, key generation, server hardening options, step‑by‑step safeguards to avoid being locked out, key‑management best practices, troubleshooting tips, and provides a complete hardening script for Linux systems.

Fail2banLinuxSSH

0 likes · 25 min read

How to Harden SSH Without Locking Yourself Out

Raymond Ops

Aug 5, 2026 · Cloud Native

How to Diagnose Kubernetes Node NotReady Issues: A Complete Step‑by‑Step Troubleshooting Guide

This guide walks Kubernetes operators through a systematic, step‑by‑step process for diagnosing nodes stuck in the NotReady state, covering kubelet status reporting, common failure reasons, detailed command‑line checks, root‑cause analysis, remediation steps, verification, and long‑term preventive measures.

KubeletKubernetesNotReady

0 likes · 42 min read

How to Diagnose Kubernetes Node NotReady Issues: A Complete Step‑by‑Step Troubleshooting Guide

Raymond Ops

Aug 4, 2026 · Operations

Uncover Hidden Nginx 502 Bad Gateway Config Pitfalls from Logs

This article explains why 502 Bad Gateway errors are the most frequent Nginx issue, quantifies their impact on business availability, and provides a systematic, log‑driven troubleshooting workflow with concrete configuration examples, health‑check setups, and production‑grade best‑practice recommendations.

502NginxReverse Proxy

0 likes · 73 min read

Uncover Hidden Nginx 502 Bad Gateway Config Pitfalls from Logs

Raymond Ops

Aug 4, 2026 · Information Security

A Miswritten iptables Rule That Almost Made Me Quit

The article recounts a real‑world iptables misconfiguration that cut off SSH access for 47 minutes, walks through the incident timeline, root‑cause analysis, and detailed remediation steps, and then expands into a comprehensive guide on iptables fundamentals, common pitfalls, best‑practice design, troubleshooting commands, automation, monitoring, and migration to nftables.

AutomationLinuxfirewall

0 likes · 71 min read

A Miswritten iptables Rule That Almost Made Me Quit

Raymond Ops

Aug 3, 2026 · Databases

How to Diagnose MySQL Slow Queries Without Relying on Blind Indexing

This guide walks through a systematic approach to uncovering and fixing MySQL slow queries, covering slow‑query‑log configuration, log analysis with mysqldumpslow and pt‑query‑digest, EXPLAIN‑based execution‑plan inspection, index design principles, SQL rewrites, configuration tuning, and ongoing monitoring to prevent performance regressions.

Database ConfigurationEXPLAINMySQL

0 likes · 27 min read

How to Diagnose MySQL Slow Queries Without Relying on Blind Indexing

Raymond Ops

Aug 2, 2026 · Artificial Intelligence

Why Your RAG Falls Short and How to Fix It: Common Pitfalls and Proven Optimizations

This article dissects why Retrieval‑Augmented Generation pipelines often underperform, examines root causes such as embedding model choice, chunking strategy, hybrid retrieval, and reranking, and provides concrete code samples, evaluation metrics, and step‑by‑step troubleshooting to dramatically improve results.

ChunkingEmbeddingEvaluation

0 likes · 18 min read

Why Your RAG Falls Short and How to Fix It: Common Pitfalls and Proven Optimizations

Raymond Ops

Aug 1, 2026 · Databases

Essential MySQL Backup and Recovery Process Every Ops Engineer Must Master

This comprehensive guide walks MySQL administrators through the fundamentals of backup and recovery, covering RPO/RTO concepts, tool comparisons (mysqldump, mydumper, xtrabackup), step‑by‑step scripts for full, incremental, and binlog backups, encryption, compression, troubleshooting, and best‑practice monitoring to ensure data safety and rapid restoration.

BackupMySQLXtraBackup

0 likes · 35 min read

Essential MySQL Backup and Recovery Process Every Ops Engineer Must Master