Knowledge Base

Guides, tutorials, and answers to help you get the most out of Xitoring.

105 articles found

How to check running processes on Ubuntu Server

Every Ubuntu Server question that starts with "why is the box slow?" or "what's listening on that port?" ends in the same place — looking at the process table. This guide covers `ps`, `top`, `htop`, `pgrep`, `systemctl`, the `/proc` filesystem, and how to map a noisy process back to the port, file, or service that owns it, with the commands and flags that actually earn their keep on a production server.

ubuntulinuxprocessespstophtopsystemdsysadmintroubleshooting

DevOps & Workflow

How to increase database performance

Most "the database is slow" problems are not the database — they're a missing index, an N+1 from the ORM, a buffer pool sized for last year's data, or a disk that quietly degraded. This guide walks the layers in the order they actually matter: measure first, fix queries and schema, then configuration, then hardware, then architecture.

databaseperformancemysqlpostgresqltuningindexesquery-optimizationsysadmindevops

Server Monitoring

How to install and configure an NTP (chrony) server on CentOS 8

CentOS 8 ships chrony as the only NTP daemon in the base repos — the classic `ntp` package is gone. This guide walks through installing chrony, configuring it as a time server for your network, opening firewalld and SELinux correctly, verifying sync, and monitoring drift on CentOS 8, CentOS Stream 8, RHEL 8, Rocky Linux 8, and AlmaLinux 8.

ntpchronycentoscentos-8rhelrocky-linuxalmalinuxlinuxtimemonitoring

Networking & Diagnostics

Install tcpdump on CentOS 7 and CentOS 8

A focused guide to installing `tcpdump` on CentOS 7 and CentOS 8, including the repository fixes both distros now need (CentOS 8 is EOL and points at vault.centos.org; CentOS 7 reached EOL in June 2024), SELinux and firewalld notes, and a smoke-test capture to confirm it actually works.

tcpdumpcentoscentos7centos8linuxnetworkingtroubleshootingrhel

DevOps & Workflow

Using MySQLTuner to optimize MySQL performance

MySQLTuner is a single-file Perl script that reads your server's status counters and configuration and prints a prioritized list of tuning recommendations. This guide covers installing it, running it safely against a live server, interpreting the output, and — just as importantly — knowing when to ignore its advice.

mysqlmariadbmysqltunerperformancetuningdatabaseinnodbsysadmin

DevOps & Workflow

Optimizing PHP-FPM for better performance

PHP-FPM has more tuning knobs than most people realize, and the defaults shipped by your distro are sized for a generic VPS — not your workload. This guide walks through what FPM actually does, how to measure where it hurts, and which settings — across the process manager, OPcache, the OS, and your web server — genuinely move the needle in 2026.

phpphp-fpmopcacheperformancetuningnginxlinuxsysadmindevops

DevOps & Workflow

Using fdisk to manage partitions on Linux

`fdisk` is the oldest, most widely-installed partition editor on Linux. This guide covers listing disks, creating and deleting partitions, working with GPT versus MBR, writing changes safely, and the modern alternatives (`parted`, `gdisk`, `sfdisk`) you should reach for when `fdisk` is the wrong tool.

fdisklinuxpartitionsdiskstoragesysadmingptmbr

DevOps & Workflow

How to add a user to sudoers in AlmaLinux or Rocky Linux

Granting sudo on AlmaLinux or Rocky Linux is a one-liner — but the right shape of that grant (wheel group vs `/etc/sudoers.d/`, password vs NOPASSWD, all commands vs a narrow list) decides whether the next admin inherits a clean setup or a footgun. This guide walks through every common way to add a user to sudoers on RHEL-derived distros, how to verify the grant works, and how to avoid the classic mistakes that lock you out of the box.

linuxalmalinuxrocky-linuxrhelsudosudoerssecuritysysadmin

DevOps & Workflow

How to Configure Jenkins with SSL Behind Nginx on Ubuntu 20.04

Jenkins ships an HTTP server on port 8080 and stops there — no TLS, no professional URL, no port-sharing with the rest of your stack. The standard fix is to put Nginx in front of it, terminate TLS with Let's Encrypt, and bind Jenkins to localhost so the only path in is through the proxy. This guide walks through every step on Ubuntu 20.04 — installing Jenkins, getting a certificate, writing a correct reverse-proxy config (with the headers Jenkins actually needs), fixing the "reverse proxy setup is broken" warning, and avoiding the WebSocket and CSRF gotchas that bite people the first time.

jenkinsnginxssltlslets-encryptubuntureverse-proxyci-cddevops

DevOps & Workflow

How to fine-tune Linux kernel parameters

Linux exposes hundreds of runtime knobs through `sysctl` — and most of the "tuning guides" you'll find on the internet are cargo-culted defaults from 2009 that may already be the kernel's default in 2026, or worse, the wrong answer for your workload. This guide walks through what kernel parameters actually are, how to change them safely, which ones genuinely matter for servers under load, and how to verify a change made things better instead of just different.

linuxkernelsysctlperformancetuningnetworkingtcpsysadmindevops