Raymond Ops
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Raymond Ops

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

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Recent Articles

Latest from Raymond Ops

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Raymond Ops
Raymond Ops
Jul 7, 2026 · Operations

Practical Guide to Diagnosing and Resolving Linux Disk Space Exhaustion

This article provides a step‑by‑step, command‑driven methodology for identifying the five root causes of full disk space on Linux systems—block exhaustion, inode depletion, deleted‑but‑still‑held files, reserved space, and filesystem corruption—and offers concrete remediation techniques, automation scripts, and best‑practice recommendations.

Disk SpaceInodeLVM
0 likes · 55 min read
Practical Guide to Diagnosing and Resolving Linux Disk Space Exhaustion
Raymond Ops
Raymond Ops
Jul 6, 2026 · Information Security

Practical Guide to Defending Against Brute‑Force Attacks with fail2ban

This step‑by‑step guide explains how fail2ban monitors logs, matches brute‑force patterns, and automatically bans malicious IPs for SSH, HTTP Basic Auth, MySQL, and custom services on Ubuntu 24.04 or Rocky Linux 9.5, including installation, configuration, testing, best practices, and troubleshooting.

Fail2banLinux firewallNginx
0 likes · 29 min read
Practical Guide to Defending Against Brute‑Force Attacks with fail2ban
Raymond Ops
Raymond Ops
Jul 5, 2026 · Operations

Building a Basic Monitoring System from Zero: How to View CPU, Memory, Disk, and Network

This article walks you through setting up a complete monitoring stack with Prometheus, node_exporter, Grafana and Alertmanager, explains how to interpret the four core dimensions—CPU, memory, disk and network—using a structured troubleshooting workflow, and provides real‑world case studies, scripts and best‑practice recommendations.

AlertmanagerGrafanaPrometheus
0 likes · 35 min read
Building a Basic Monitoring System from Zero: How to View CPU, Memory, Disk, and Network
Raymond Ops
Raymond Ops
Jul 4, 2026 · Operations

Using tcpdump to Pinpoint Online Network Anomalies

This guide explains how tcpdump, built on libpcap and the kernel BPF filter, can capture packets at the network stack, compares it with Wireshark, shows practical filtering syntax, performance considerations, typical use‑cases such as TCP retransmission, DNS timeouts and TLS handshake failures, and provides scripts and best‑practice recommendations for production‑grade troubleshooting.

BPFPerformance MonitoringWireshark
0 likes · 39 min read
Using tcpdump to Pinpoint Online Network Anomalies
Raymond Ops
Raymond Ops
Jul 3, 2026 · Operations

10 Rookie Ops Mistakes You Must Avoid – A Complete Checklist

This guide walks ops newcomers through the ten most common pitfalls—from accidental rm‑rf deletions and mis‑configured firewalls to unsafe chmod usage—and provides concrete remediation steps, ready‑to‑run shell scripts, best‑practice checklists, and monitoring setups to keep production environments stable and secure.

DevOpsShell Scriptinglinux
0 likes · 51 min read
10 Rookie Ops Mistakes You Must Avoid – A Complete Checklist
Raymond Ops
Raymond Ops
Jul 3, 2026 · Operations

Practical Guide to Diagnosing and Fixing NFS Mount Failures

This guide explains the NFS protocol, common mount failures, five root‑cause categories, step‑by‑step installation, configuration, verification, detailed error analysis, real‑world case studies, performance tuning, automation scripts, best‑practice recommendations and monitoring techniques for reliable NFS deployments on Ubuntu 24.04 and Rocky Linux 9.5.

MountNFSautomation
0 likes · 52 min read
Practical Guide to Diagnosing and Fixing NFS Mount Failures
Raymond Ops
Raymond Ops
Jul 2, 2026 · Operations

How to Monitor Large Model Applications: A Beginner‑Friendly Metric System

This guide walks you through building a production‑grade monitoring solution for large language model inference services using a three‑layer metric hierarchy, Prometheus, Grafana, DCGM Exporter, and custom Python metrics, with step‑by‑step deployment, alerting policies, and real‑world troubleshooting examples.

AI infrastructureGrafanaLarge Language Models
0 likes · 42 min read
How to Monitor Large Model Applications: A Beginner‑Friendly Metric System
Raymond Ops
Raymond Ops
Jul 2, 2026 · Information Security

Linux Security Hardening in Practice: 20 Essential Configurations Explained

This comprehensive guide walks you through Linux system hardening by outlining default settings, common pitfalls, and a step‑by‑step checklist of 20 critical configurations covering account policies, SSH, firewall, kernel parameters, file permissions, and audit logging, complete with verification commands, rollback procedures, and real‑world case studies.

SSHauditcompliance
0 likes · 37 min read
Linux Security Hardening in Practice: 20 Essential Configurations Explained
Raymond Ops
Raymond Ops
Jul 1, 2026 · Operations

Memory Leak Postmortem: Combining free, smem, pmap, and perf for Effective Diagnosis

When a thumbnail service experienced sudden latency spikes and OOM kills shortly after a new release, the author walks through a systematic investigation using free, smem, pmap, and perf to distinguish true memory leaks from page‑cache or shared‑page artifacts, pinpoint the native decoder buffer issue, and outline remediation steps.

KubernetesMemory Leaklinux
0 likes · 29 min read
Memory Leak Postmortem: Combining free, smem, pmap, and perf for Effective Diagnosis
Raymond Ops
Raymond Ops
Jun 30, 2026 · Operations

How to Use SonarQube for Code‑Quality Scanning and Eliminate Bugs

This article explains why code‑quality issues are a major source of technical debt, introduces SonarQube’s multi‑language static analysis, describes its core features such as multi‑dimensional analysis, incremental scans and Quality Gates, and provides step‑by‑step deployment, configuration, CI/CD integration, best‑practice recommendations, troubleshooting tips and monitoring scripts to ensure reliable, secure and scalable code‑quality management in production environments.

CI/CDCode QualityDevOps
0 likes · 34 min read
How to Use SonarQube for Code‑Quality Scanning and Eliminate Bugs