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.
This article walks through a systematic, step‑by‑step troubleshooting guide for MySQL "Too many connections" errors, showing how to verify the symptom, inspect server variables, analyze connection status, identify common root causes such as connection‑pool misconfiguration, leaked connections, and long‑running queries, and apply safe fixes and preventive measures.
A production incident showed Redis keys disappearing at 2 AM without any memory alarms; deep analysis revealed a short‑term memory spike caused by a surge in GET requests, client‑output‑buffer‑limit growth, and LRU eviction, leading to practical mitigation steps.
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.
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.
This guide walks through a systematic, four‑layer analysis of Nginx 502, 504 and connection‑timeout failures, showing how to split the request path, collect logs and metrics, verify upstream health, adjust timeouts, and apply best‑practice configurations to quickly locate and resolve production issues.
This article walks through the symptoms, root cause analysis, and step‑by‑step solutions for uneven CPU usage across Java service instances, highlighting how mismatched Kafka partition counts and thread or GC issues can lead to load imbalance and how to resolve them.
Disabling ping blocks ICMP Echo Reply responses, reducing exposure to network scans and ICMP flood attacks, but also hampers troubleshooting, monitoring, and cloud health checks, so the decision should consider device location, monitoring needs, and potential impact on maintenance.
When a Java application suddenly hits 100% CPU and becomes unresponsive, this guide walks through a three-step investigation—identifying the hottest process, the most CPU-intensive thread, and the offending code—using tools like top, jstack, and Arthas, and presents common causes and preventive measures.
This article presents a systematic, evidence‑driven process for locating and resolving high CPU usage on Linux servers, covering environment preparation, layered troubleshooting from whole‑machine to thread level, concrete command examples, real‑world case studies, best‑practice recommendations, and monitoring configurations.
This article walks system administrators and DevOps engineers through a systematic approach to diagnosing Linux network issues, covering the fundamentals of netstat, ss, and tcpdump, interpreting TCP state tables, analyzing packet captures, and resolving common problems such as TIME_WAIT buildup, SYN floods, and HTTPS handshake failures.
The article explains that disabling ping blocks only ICMP Echo Reply traffic, outlines security benefits such as preventing network scans and mitigating ICMP flood attacks, discusses practical drawbacks for troubleshooting and monitoring, and offers scenario‑based guidance on when to enable or disable ping.
This handbook provides a thorough overview of Ceph’s architecture and core principles, followed by detailed step‑by‑step instructions for common cluster operations, fault diagnosis, and advanced configuration, serving both newcomers and experienced administrators seeking to master Ceph storage management.
This comprehensive guide walks you through OpenStack deployment from a single‑node DevStack test to a production‑grade HA cluster with Kolla‑Ansible, covering hardware planning, component configuration, performance tuning, network setup, troubleshooting, monitoring, backup strategies, and useful operational scripts.
This article provides a comprehensive, step‑by‑step guide to Linux disk fundamentals, partitioning tools, mounting options, filesystem choices, LVM management, performance tuning, common error diagnostics, and five real‑world troubleshooting cases, enabling sysadmins to confidently manage and resolve disk‑related problems.
This article provides a concise, step‑by‑step reference of the most frequently used kubectl commands for Kubernetes, explaining each command's purpose, typical scenarios, useful options, and the information it reveals to help operators troubleshoot clusters, nodes, pods, deployments, logs, and resources.
This guide walks through Ceph’s architecture, deployment with cephadm, hardware selection, common failure scenarios, and practical performance tuning steps, offering concrete commands and best‑practice recommendations to keep a Ceph cluster stable and efficient.
This guide explains how to interpret Nginx access and error logs, understand the meaning of each log field, configure timeout directives across client, Nginx, upstream, and FastCGI layers, troubleshoot common 4xx and 5xx status codes, and use practical command‑line tools and analysis pipelines to quickly locate and resolve performance and connectivity issues.
A production change replaced two Nginx reverse‑proxy servers, introduced an upstream name containing an underscore, broke the Host header required by HTTP/1.1, and caused Spring Cloud Gateway to return 400 Bad Request for every request until the configuration was corrected.
A comprehensive, step‑by‑step guide that explains the most common Kubernetes failure scenarios—from pod crashes and image pull errors to node NotReady and API server timeouts—provides concrete kubectl commands, diagnostic scripts, real‑world case studies, best‑practice recommendations, monitoring metrics, and backup‑restore procedures to keep production clusters healthy.
This article presents a systematic, USE‑methodology‑based workflow for diagnosing Linux performance issues, covering CPU, memory, disk I/O and network bottlenecks with step‑by‑step commands, detailed examples, scripts, case studies, best‑practice recommendations and monitoring guidelines.
When a teammate struggled to find errors in massive Java service logs, the author demonstrated a step‑by‑step series of grep tricks—locking time and identifiers, chaining filters, using line numbers, context options, real‑time tailing, recursive search, and shell aliases—to turn chaotic log streams into precise, actionable insights.
This guide compiles over 200 practical kubectl commands, covering cluster setup, context switching, resource inspection, workload management, networking, storage, security hardening, high‑availability patterns, troubleshooting techniques, and performance monitoring to help operators efficiently administer Kubernetes environments.
This article provides a concise, step‑by‑step guide to the fifteen most frequently used Nginx commands, showing how to check versions, start, stop, reload, test configurations, view logs, monitor connections and ports, and troubleshoot common errors on Linux systems.
This article explains that CrashLoopBackOff is a symptom, not the root cause, and walks through a production‑grade troubleshooting workflow—including checking pod status, describing events, examining logs (current and previous), and exec‑ing into containers—while covering common failures such as OOMKilled, liveness‑probe misconfiguration, bad config files, database connection issues, image command errors, and disk‑pressure problems, and warns against premature pod deletion.
Nginx 502 Bad Gateway is one of the most frequent operational issues; this article outlines a systematic, layered approach—from checking Nginx error logs and backend service status to network connectivity, resource limits, timeout settings, and permission problems—providing concrete commands, example scenarios, and preventive measures to quickly identify and resolve the root cause.
This article walks through a systematic network troubleshooting workflow on Linux, detailing how to use ss to inspect sockets, ip for routing and address information, tc for traffic control at the link layer, and ethtool for hardware diagnostics, with concrete command examples and practical tips.
This article enumerates ten uncommon, compaction‑related problems encountered in large‑scale Paimon deployments, explains their root causes—such as RPC timeouts, snapshot expiration, file corruption, and write conflicts—and provides concrete configuration tweaks and operational steps to resolve each issue.
This guide walks you through a systematic, multi‑stage process for diagnosing and fixing DNS resolution failures, covering symptom identification, tool preparation, local resolver checks, authoritative server analysis, common root causes, advanced diagnostics, and post‑fix validation with concrete commands and examples.
The article explains why Full GC should be minimized, defines normal versus abnormal GC frequencies, outlines the root causes of Full GC, and provides a step‑by‑step troubleshooting workflow with concrete code snippets, monitoring commands and real‑world examples for Java backend engineers.
This article explains the three classic Redis cache problems—avalanche, penetration, and breakdown—detailing their definitions, typical symptoms, step‑by‑step troubleshooting procedures, root‑cause analysis, and practical mitigation strategies such as random expiration, empty‑value caching, Bloom filters, distributed locks, and multi‑level cache architectures.
This guide introduces ten essential Linux commands—htop/btop, glances, ncdu, journalctl, ss, tree, watch, xz/zstd/pigz, mtr, and jq—explaining their problem contexts, step‑by‑step usage, risk warnings, and verification methods so you can troubleshoot servers faster and cut routine work time in half.
This article provides a comprehensive, step‑by‑step analysis of Kubernetes Pods, covering their design as a shared‑namespace container group, the role of the pause (infra) container, creation flow, lifecycle phases, resource requests and limits, QoS classes, scheduling mechanics, volume types, and detailed troubleshooting techniques with concrete command‑line examples.
This comprehensive guide walks Linux system administrators through a systematic performance‑troubleshooting workflow, covering CPU, memory, disk I/O, and network analysis with concrete commands, metrics, common bottleneck causes, real‑world case studies, and practical optimization recommendations.
This guide walks Linux operators through the core log architecture, essential log files, powerful command‑line tools such as grep, awk, sed and journalctl, and step‑by‑step troubleshooting scenarios—including SSH connectivity, service failures, disk space, memory leaks, security incidents, and application logs—while providing ready‑to‑run scripts and advanced techniques for automated and centralized log analysis.
This article compiles the ten most frequent Docker problems encountered in production—such as disk exhaustion, time drift, DNS failures, OOM kills, data loss, tag confusion, signal handling, resource‑limit oversights, and exposed daemon ports—provides concrete symptoms, root‑cause explanations, diagnostic commands, remediation steps, and preventive measures, and also lists five often‑overlooked traps.
This guide walks operators through a systematic, step‑by‑step process for diagnosing Docker container startup failures, covering status checks, log inspection, detailed use of docker inspect, and categorized troubleshooting of image, configuration, resource, permission, network, and volume issues with concrete commands and examples.
This article explains how to identify and troubleshoot the four main resource bottlenecks—CPU, memory, disk I/O, and network—by detailing Linux internals, key metrics, practical command examples, real‑world case studies, and a step‑by‑step decision tree for accurate diagnosis and tuning.
This article explains what network packet loss is, its common causes—from hardware faults to congestion and misconfiguration—and provides a step‑by‑step, production‑ready methodology for diagnosing and resolving loss using tools such as ping, traceroute, Wireshark and tcpdump.
When a website’s response time jumped from 200 ms to over 10 seconds, this guide walks through a layered investigation—from confirming the scope, checking Nginx and upstream health, analyzing application logs, inspecting MySQL processes, slow queries, and locks, to examining server CPU, memory, disk I/O, and network—providing concrete commands, expected outputs, and root‑cause patterns for effective troubleshooting and preventive monitoring.
The article systematically reviews ten typical Nginx configuration pitfalls that frequently trigger production incidents—such as location‑matching errors, proxy_pass slash issues, misuse of try_files, insufficient keepalive settings, client_max_body_size limits, gzip misconfiguration, incomplete TLS setup, worker process limits, log‑rotation problems, and exposed server version—providing a clear phenomenon → root cause → correct configuration → verification → risk reminder workflow for each, plus a comprehensive troubleshooting path, checklist, and rollback script for safe production changes.
This guide explains how to distinguish the root causes of 502 Bad Gateway, 504 Gateway Timeout, and Connection Reset errors in Nginx reverse‑proxy deployments and provides a step‑by‑step, four‑segment troubleshooting workflow with concrete log patterns, shell commands, and configuration tweaks.
This guide walks Linux operators through a systematic, four‑dimensional investigation of server slowdown—covering CPU, memory, disk I/O, and network—using concrete commands, diagnostic scripts, real‑world scenarios, and step‑by‑step remediation strategies to pinpoint and resolve performance bottlenecks.
This article walks Kubernetes operators through a systematic investigation of NotReady node symptoms, explaining the kubelet status mechanism, detailing each diagnostic step—from verifying node conditions with kubectl to checking kubelet, container runtime, resources, network, and certificates—and providing concrete remediation and preventive measures.
This article walks you through a systematic, step‑by‑step process for diagnosing and fixing MySQL CPU usage spikes—from identifying the symptoms and gathering system metrics, to pinpointing problematic queries, analyzing locks and buffers, applying index and configuration tweaks, and validating the performance gains with real‑world examples and command‑line tools.
This article provides a systematic, layer‑by‑layer troubleshooting guide for Kubernetes service connectivity problems, covering pod health, service and endpoint configuration, kube‑proxy rules, CNI plugins, Ingress controllers, DNS resolution, and NetworkPolicy, with concrete commands, examples, and preventive scripts.
An online education platform experienced a massive outage when Redis hit its maxclients limit, causing authentication, session, and cache services to fail, which cascaded into a business avalanche; the article walks through the connection mechanism, root‑cause analysis, rapid mitigation steps, and long‑term safeguards.
When a Linux server reports a full disk, this guide walks you through eight essential commands to diagnose whether the issue is actual space exhaustion, inode depletion, lingering deleted files, or I/O bottlenecks, and provides a systematic cleanup workflow for production environments.
During a mid‑year promotion an e‑commerce platform experienced a sudden spike in load average and response latency; the article walks through a systematic, command‑driven investigation that identifies an I/O bottleneck caused by mis‑configured log rotation and excessive debug logging, and presents immediate and long‑term remediation steps.
This article explains Linux Load Average’s definition, how the three numbers are calculated, their relationship with CPU and I/O, practical interpretation rules, step‑by‑step troubleshooting workflows, monitoring setups, and optimization techniques for both CPU‑bound and I/O‑bound load spikes.
The article explains how MySQL InnoDB deadlocks occur, details the four necessary conditions, shows how to enable full deadlock logging, demonstrates queries against information_schema and performance_schema, and provides concrete scenarios with code‑level solutions to prevent and resolve deadlocks in production environments.
This guide systematically dissects the root causes of Nginx 502 Bad Gateway errors, explains how to read and interpret error logs, and provides detailed step‑by‑step troubleshooting, configuration adjustments, health‑check setups, and preventive monitoring strategies for modern production environments.
When MySQL CPU usage spikes above 80% or hits 100%, this guide walks you through a systematic investigation—from confirming the MySQL process consumes CPU, checking system and MySQL status, analyzing connection counts, slow queries, lock waits, and configuration settings, to applying short‑term mitigations and long‑term architectural fixes.
This step‑by‑step guide shows how to configure networking on Ubuntu/Debian with netplan, CentOS/RHEL with nmcli, Arch Linux with systemd‑networkd, and Alpine with ifupdown, plus common debugging commands and a systematic troubleshooting workflow.
This guide walks you through identifying why MySQL CPU usage jumps, from confirming the MySQL process consumes CPU to checking connection counts, slow queries, lock waits, configuration settings, and business‑level traffic, and then provides short‑term mitigations and long‑term solutions such as read‑write splitting, sharding, and caching.
This comprehensive guide walks operators through the entire Kubernetes workflow from creating a Deployment to exposing a Service, explaining core resources, control loops, scheduling, networking, rolling updates, troubleshooting steps, best‑practice configurations, performance tuning, and security hardening.
This guide walks operations engineers through a systematic, multi‑layered approach to identifying why static resources load slowly, covering data collection, network diagnostics, server configuration, application settings, client‑side checks, common failure scenarios, and automated monitoring scripts.
This guide presents a step‑by‑step, standardized process for detecting, analyzing, and fixing sudden CPU usage spikes on Linux servers, covering preparation, quick identification, deep thread‑level investigation, stack and system‑call analysis, flame‑graph generation, emergency mitigation, and best‑practice recommendations.
This comprehensive guide explains the differences between Nginx 502 and 504 errors, provides step‑by‑step troubleshooting procedures, detailed configuration examples, one‑click diagnostic scripts, real‑world case studies, best‑practice optimizations, monitoring setups, and advanced learning paths to help you quickly resolve gateway issues and improve server reliability.
When a Linux server feels sluggish yet appears healthy, this guide walks you through systematic checks—kernel load, process inspection, and targeted monitoring—to pinpoint the root cause and resolve performance issues without resorting to an immediate reboot.
This guide walks you through systematic troubleshooting of Java service performance problems—covering CPU spikes, memory leaks, GC pauses, disk I/O anomalies, and network bottlenecks—by explaining key metrics, command‑line tools, visual profilers, and practical code examples.
This step‑by‑step guide explains how to safely upgrade from Ubuntu 24.04 LTS to the new 26.04 LTS, covering pre‑upgrade backups, hardware checks, three upgrade methods, post‑upgrade cleanup, performance tuning, and troubleshooting for common issues.
This article explains the HTTP 5xx status codes 502, 503, and 504, detailing their definitions, typical trigger scenarios, step‑by‑step troubleshooting flows, practical Bash scripts, comparison tables, real‑world case studies, and monitoring/alerting configurations to help operations engineers quickly pinpoint and resolve these errors.
This guide explains why MySQL reports “Too many connections”, walks through emergency assessment steps, provides practical commands and scripts to stop the bleeding, analyzes root causes such as slow queries, connection leaks, short‑lived connections or low max_connections settings, and offers long‑term remediation and monitoring solutions for production environments.
This guide walks operations engineers through every detail of the TCP protocol—from header fields and flag meanings to the three‑way handshake, four‑way teardown, state diagrams, common pitfalls, and practical Wireshark analysis—providing Linux commands, code examples, and troubleshooting tips for reliable network management.
This comprehensive guide explains the HTTP 5xx status code hierarchy, details the specific triggers and root causes of 502 Bad Gateway, 503 Service Unavailable, and 504 Gateway Timeout, and provides step‑by‑step diagnostic flowcharts, real‑world case studies, and ready‑to‑run scripts for rapid resolution and proactive monitoring.
This comprehensive guide walks you through Systemd fundamentals, core systemctl commands, unit file anatomy, custom service creation, common troubleshooting, performance tuning, timer and socket activation, and best‑practice security hardening for Linux administrators.
This guide explains the DNS resolution process, categorises common failure types, provides step‑by‑step troubleshooting procedures, essential commands, configuration examples for systemd‑resolved, BIND9, Unbound and CoreDNS, and offers best‑practice recommendations for reliable DNS operation in Linux and Kubernetes environments.
This guide walks through a step‑by‑step process for identifying the partitions and files that fill a disk, applying temporary fixes to bring usage below critical levels, and implementing long‑term measures to prevent future disk‑full incidents in production environments.
This article explains why Ollama has become popular for local LLM deployment, outlines its core features, and provides a detailed, step‑by‑step tutorial for integrating OpenClaw with Ollama—including model selection, configuration, troubleshooting common errors, and advanced tips for customization and multi‑model switching.
This article breaks down OpenClaw’s five‑layer runtime—channel, account, agent, session, and memory—explaining common “mystical” issues, offering concrete diagnostics, configuration tips, and step‑by‑step commands so developers can quickly identify why a bot doesn’t reply, loses context, or forgets prior messages.
This guide walks you through the 17 most common OpenClaw issues—from installation and Node.js version mismatches to gateway port conflicts, token authentication failures, channel integration quirks, multi‑agent communication problems, and performance bottlenecks—providing step‑by‑step diagnostics, concrete command‑line examples, scripts and preventive measures to help you avoid hours of troubleshooting.
This guide walks through Kubernetes pod lifecycle phases, container states, restartPolicy options, health‑check probes, lifecycle hooks, init containers, common troubleshooting scenarios such as CrashLoopBackOff, Pending and Stuck Terminating, and provides best‑practice recommendations for configuration, graceful shutdown, resource limits and monitoring.
A comprehensive, step‑by‑step guide for SREs and DevOps engineers to diagnose and resolve common Kubernetes pod issues—including CrashLoopBackOff, OOMKilled, ImagePullBackOff, Pending, Evicted, and Terminating—by leveraging pod lifecycle knowledge, kubectl commands, logs, events, node inspection, scripts, real‑world case studies, and monitoring best practices.
This comprehensive guide explains NFS fundamentals, version differences, mounting procedures, common failure categories, core concepts like RPC and file handles, environment requirements, step‑by‑step installation and configuration, performance tuning parameters, real‑world case studies, monitoring, backup, and best‑practice recommendations for reliable NFS deployments.
This guide explains why Cursor Free VIP reports a missing file when resetting the machine ID after an update, and provides step‑by‑step solutions—including reinstalling to the correct folder, copying resources, and editing the config file—to restore proper functionality on Windows.
This guide walks you through detecting, analyzing, and resolving Linux CPU spikes by monitoring overall load, pinpointing the offending process, drilling down with tools like top, ps, strace, perf, and sar, and applying targeted fixes for the ten most common causes.
This guide walks you through a systematic, top‑to‑bottom troubleshooting flow for Kubernetes, covering pod pending problems, container start failures, readiness checks, service misconfigurations, ingress routing errors, and storage pitfalls, with concrete kubectl commands and practical fixes.
This guide explains why MySQL replication lag spikes, how to distinguish IO‑thread pull problems from SQL‑thread apply bottlenecks, provides step‑by‑step commands, configuration examples, real‑world case studies, best‑practice recommendations, and monitoring setups to reliably troubleshoot and prevent replication delays.
This comprehensive guide walks you through Kubernetes fault‑tolerance by covering core components, classifying six major failure types, presenting a three‑step troubleshooting methodology, and detailing six real‑world case studies with commands, manifests, monitoring setups and preventive best practices.
This guide lists frequent Jenkins problems such as missing libXrender.so.1 and SSH transferring zero files, explains why they occur, and provides exact yum commands, path-adjustment tips, and shell-parameter checks to resolve them.
This guide explains what Zabbix is, outlines its key monitoring features, provides step‑by‑step commands for installing and configuring Zabbix on Debian/Ubuntu systems, and offers practical troubleshooting tips for logs, services, database connections, and web server settings.
This guide presents a systematic, four‑dimensional USE methodology for diagnosing Linux performance issues, walking through quick 60‑second overviews with top, vmstat, iostat and ss, then diving into detailed CPU, memory, disk I/O and network investigations using tools such as mpstat, perf, bpf, and flame graphs.
This article explores the strategic role of eBPF in cloud‑native operations, detailing its technical foundations, real‑world use cases from major tech companies, step‑by‑step troubleshooting methods, and a concrete implementation for TCP retransmission monitoring in a high‑traffic gateway system.
This guide explains why Cursor Free VIP shows a file‑not‑found error after updating, and provides four practical solutions: reinstalling to the correct folder, copying resources, changing the default install path, and adjusting the config.ini file, followed by testing steps.
This article demystifies the ping command by explaining the ICMP protocol, interpreting TTL, latency and packet‑loss metrics, detailing the five‑step process from DNS lookup to reply, and highlighting ping’s inherent limitations such as its inability to gauge bandwidth, application‑layer issues, or firewall restrictions.
This guide lists the most useful kubectl commands for inspecting cluster health, creating and deleting resources, accessing logs, exposing services, managing labels, scaling workloads, performing rolling updates, rolling back revisions, and copying files between pods and the local machine.
When a PHP script calls SoapClient and the returned data is always empty, the likely cause is that the SOAP extension is not enabled in the PHP configuration, which can be resolved by editing php.ini to activate the extension and restarting the server.
This guide explains how to recover a multi-node OCP cluster after a failed NLB upgrade by diagnosing METADB connection errors, extracting VIP/PORT information, and re-creating NLB load-balancing rules through Docker and nlbcli commands, ensuring the cluster becomes reachable again.
This guide explains why using OAT to add a server can render yum unusable due to a broken Python interpreter, analyzes the underlying script logic that causes the failure, and provides two practical remediation methods—including fixing the Python symlink and adjusting the installation script—along with the full script for reference.
A real‑world production incident where GC pauses, thread‑pool exhaustion, and slow SQL combined to drop QPS from 3000 to 1400 and inflate response times from 200 ms to over 2 s, with detailed analysis, diagnostic criteria, and step‑by‑step optimizations that restored performance.
This guide systematically covers common Maven dependency resolution failures—including stale SNAPSHOTs, missing artifacts, version mismatches, and local‑only builds—by explaining underlying mechanisms, providing a step‑by‑step troubleshooting checklist, and offering concrete commands and configuration examples to resolve each scenario.
This article presents a systematic methodology and a curated set of Linux tools—including CPU, memory, disk I/O, network, load monitoring, and flame‑graph techniques—illustrated with a real‑world nginx case study to help engineers quickly locate and resolve performance issues.
This guide explains how Claude Code’s new LSP feature, introduced in version 2.0.74, brings IDE‑grade code navigation, reference search, and real‑time diagnostics to the CLI, dramatically cutting symbol lookup from seconds to about 50 ms, and provides step‑by‑step configuration, language‑specific setup, advanced usage, and troubleshooting tips.
This guide walks through diagnosing intermittent 502 Bad Gateway errors in Nginx by analyzing error logs, checking upstream and FastCGI timeout settings, reviewing PHP‑FPM configuration, performing performance tuning, and outlining advanced troubleshooting, monitoring, and capacity‑planning strategies to ensure stable high‑traffic deployments.
This article walks through a production incident where Redis began returning missing keys, detailing the step‑by‑step diagnosis—from monitoring logs and TTL checks to discovering memory spikes caused by client‑output‑buffer‑limit overflow and pipeline traffic—followed by emergency and permanent remediation measures.
This article presents a concise, hands‑on guide to fifteen powerful yet often overlooked Linux utilities—such as strace, perf, bpftrace, tc, hdparm, socat, dstat, fzf, yq, and more—explaining when to use each, providing concrete command examples, and highlighting why they are critical for diagnosing and fixing production‑grade DevOps incidents.
This guide shows Linux administrators step‑by‑step how to locate reboot timestamps, retrieve full reboot histories, examine log files, analyze kernel and crash logs, check service and resource issues, and investigate human or scheduled actions, enabling fast root‑cause diagnosis of unplanned server restarts.
This guide walks you through a step‑by‑step process for quickly identifying the cause of high CPU usage in ClickHouse, from emergency triage and precise diagnosis using system tables to practical optimization techniques and a ready‑to‑run monitoring script.
After updating a core API's SSL certificate, a partner reported repeated SSLHandshakeException errors, mistakenly labeling the cert as a development version; thorough verification revealed the issue stemmed from an outdated Java trust store lacking the new Sectigo root, leading to a set of concrete remediation steps and best‑practice lessons.
