Linux ops automation, cloud-native, Kubernetes, SRE, DevOps, Python, Golang and related tech discussions.
This guide walks ops engineers through installing nmap, understanding its scan techniques, executing single‑port, common‑port, full‑range, and script‑based scans, analyzing results, and applying remediation steps such as firewall rules, service hardening, and regular scanning schedules to keep server exposure minimal.
This article explains why MySQL deadlocks occur in production, distinguishes them from simple lock waits, and provides a step‑by‑step guide—including enabling deadlock logging, analyzing InnoDB lock types, and applying four practical solutions such as distributed locks, unique constraints, isolation‑level changes, and SQL reordering—to reliably troubleshoot and prevent deadlocks.
This comprehensive guide walks junior to mid‑level system administrators through Linux log fundamentals, essential command‑line tools like grep, awk, sed and journalctl, and step‑by‑step troubleshooting scenarios for SSH, service failures, disk space, memory leaks, security incidents, and application logs, providing practical scripts and advanced techniques for effective log‑driven problem resolution.
This article reviews ten common Nginx configuration mistakes that frequently trigger production incidents, explains the underlying causes, provides corrected configurations, verification steps, and risk warnings, and offers a systematic troubleshooting workflow for operators to quickly diagnose and resolve issues.
When a server is exposed to the Internet, SSH brute‑force attempts are inevitable; this guide walks Linux operators through log analysis, disabling password authentication, enabling public‑key and 2FA, configuring fail2ban, changing the default port, restricting source IPs, deploying OSSEC, and automating daily and weekly security checks.
This guide walks operators through the most frequent reasons Docker containers fail to start—such as image issues, misconfigurations, resource limits, permission problems, network errors, and volume mishaps—and provides a step‑by‑step command checklist to diagnose and fix each scenario.
This guide explains the distinct causes of 502 Bad Gateway, 504 Gateway Timeout, and Connection Reset errors in Nginx reverse‑proxy setups and provides a step‑by‑step, four‑segment troubleshooting workflow with concrete log examples, shell commands, and configuration recommendations.
This article explains how to use Nginx's built‑in limit_req and limit_conn modules—based on the leaky‑bucket algorithm—to throttle requests by IP or API key, configure burst and nodelay behavior, apply whitelists, customize error responses, fine‑tune with delay and dry‑run modes, and monitor effectiveness in production environments.
This article enumerates the ten most frequent Docker problems encountered in production—such as disk exhaustion, time drift, DNS failures, OOM kills, network issues, data loss, tag confusion, PID‑1 signal handling, missing resource limits, and exposed daemon ports—detailing their symptoms, underlying causes, diagnostic commands, remediation steps, and preventive measures, plus five additional hidden traps.
This guide walks operations engineers through the background, requirements, typical audit findings, step‑by‑step remediation commands, and verification methods for the most frequent security configuration problems encountered when implementing GB/T 22239‑2019 Level‑2/3 compliance on CentOS 7/8 and Ubuntu 20.04, covering identity authentication, access control, auditing, intrusion prevention, resource limits, and data confidentiality.
