This comprehensive tutorial walks you through installing and configuring the ELK stack (Elasticsearch, Logstash, Kibana) on CentOS, covering environment setup, component installation, node configuration, plugin integration, index creation, and log visualization with code snippets and screenshots.
This guide walks you through installing and configuring a KVM virtualization platform on Linux, covering its advantages and drawbacks, setting up local repositories, verifying hardware support, creating storage pools and volumes, importing ISO images, allocating resources, and launching a virtual CentOS 7 machine using virt‑manager.
This tutorial walks through configuring a Linux firewall and web server, setting up network interfaces across four virtual machines, enabling NAT, defining DMZ zones, securing SSH on a non‑standard port, and verifying connectivity, providing a comprehensive hands‑on guide for robust network security.
This guide explains how to install Ansible, use its basic commands and playbooks, and create a complete automation workflow to install Docker and Docker‑Compose on CentOS, covering installation methods, directory structure, built‑in modules versus shell commands, and conditional task execution with register and when.
Learn how to set up a complete email system on CentOS 7 using Postfix, Dovecot, MariaDB, Nginx, and Roundcube, covering software installation, configuration, database setup, SSL/TLS, DKIM, SPF, DMARC, and testing, with detailed commands and troubleshooting tips.
This guide walks through fifteen practical steps to secure a CentOS 7 or 8 server, covering user management, SSH hardening, password policies, file permissions, logging, and kernel protections, each with clear commands and explanations to reduce attack surface.
Learn step-by-step how to mount a CentOS ISO into rescue mode, activate LVM volumes, run XFS repair (or ext4 fsck), and then restore a Windows Server 2022 virtual machine’s bootloader using diskpart, bootrec, and bcdboot commands, ensuring both Linux and Windows systems boot correctly.
This article details a step‑by‑step rescue of a CentOS 7 server that failed with GLIBC errors after mixing CentOS 7 and CentOS 8 packages, showing how to mount the ISO, reinstall glibc, fix broken symlinks, restore PAM, Python, and other core components until the system boots normally.
This tutorial walks you through preparing separate site directories, editing Tomcat's server.xml to define Host entries, restarting the service, and testing each domain, while also covering firewall, DNS, and production‑grade security considerations for deploying multiple websites on a single CentOS server.
This tutorial walks you through removing old Docker packages, configuring yum repositories (official and Alibaba Cloud mirrors), installing a specific Docker Engine version, setting up image acceleration, verifying Docker, installing Docker‑Compose, downloading and configuring Harbor, and finally validating the Harbor registry on a CentOS system.
This tutorial walks through preparing three CentOS 7 hosts, installing Docker and Kubernetes components, initializing a master node, handling common errors, joining worker nodes, installing a CNI plugin, testing the cluster, and provides essential kubectl commands for ongoing management.
This tutorial walks you through checking the current OpenSSH version, installing required dependencies, downloading the 8.4p1 source package, backing up existing SSH files, compiling and installing the new version, updating the configuration, and verifying the upgrade on a CentOS 7 system.
This guide walks through using Hyper‑V's Virtual Switch Manager to set up a Default Switch with NAT, configure the vEthernet adapters, and manually assign static IP, gateway, netmask, and DNS on a CentOS 7.9 VM so it gains network connectivity.
This guide walks you through downloading and installing Nginx on CentOS, locating its directories, checking service status, viewing version, managing processes, testing configuration syntax, and restarting the server, all with clear commands and illustrative screenshots.
This tutorial walks through installing Samba on CentOS 7, creating system and Samba users, setting up a shared directory, configuring smb.conf, starting services, and then configuring a client to connect, mount, and auto‑mount the share using CIFS, providing a complete end‑to‑end solution.
This tutorial walks through configuring an NFS server and client on CentOS 7, installing the LAMP stack, setting up a virtual host, deploying WordPress, configuring the MySQL database, and verifying the site works, providing complete command‑line instructions and code snippets.
Learn how to create, configure, and manage a software RAID 5 array on CentOS 7 using mdadm, covering partition preparation, RAID creation, filesystem formatting, mounting, status checks, hot‑spare handling, device removal, and expansion, with complete command examples and expected outputs.
Learn how to configure Tomcat virtual hosts on a CentOS server to host multiple websites with different domain names, covering directory preparation, server.xml modifications, restarting Tomcat, testing access, firewall and DNS considerations, and essential tips for a reliable deployment.
This guide provides step‑by‑step instructions for installing Docker Engine on a CentOS 7 system, including removal of any existing Docker packages, adding the Alibaba Cloud yum repository, installing required utilities, starting and enabling the Docker service, and verifying the installation.
This guide walks you through installing software on CentOS using three primary methods—source/tarball compilation, RPM packages, and Yum—demonstrating each approach with real‑world examples such as Redis, RabbitMQ, and Nginx, and covering essential concepts, commands, and configuration steps.
Learn step‑by‑step how to install, configure, and launch an NFS server on CentOS 7, set up shared directories, edit export rules, adjust firewall settings, and mount the share on client machines, enabling reliable network file sharing for distributed and containerized environments.
This article explains what KVM is, lists its advantages and drawbacks, and provides a step‑by‑step tutorial—including repository configuration, required package installation, kernel module verification, libvirtd service setup, network bridge creation, storage pool and volume creation, ISO import, and virtual machine provisioning—complete with command snippets and screenshots, culminating in a fully functional CentOS 7 VM.
This comprehensive tutorial walks you through setting up the ELK (Elasticsearch, Logstash, Kibana) stack on CentOS, covering environment preparation, installation of each component, configuration details, health checks, plugin integration, and how to ingest system and Apache logs for visual analysis.
Learn how to configure Tomcat virtual hosts on a CentOS server to host multiple websites with distinct domain names, covering directory preparation, server.xml modifications, firewall and DNS settings, testing, and restart procedures, complete with code snippets and practical tips.
This guide walks you through a series of practical security measures for CentOS 7/8—including creating non‑root users, tightening SSH settings, enforcing password policies, securing logging, and applying kernel hardening—so you can significantly reduce the risk of unauthorized access and system compromise.
After CentOS 7 reaches end‑of‑life on June 30 2024, this guide explains why you must migrate, outlines three essential pre‑migration preparations, and provides detailed step‑by‑step commands to upgrade first to AlmaLinux 8 and then to AlmaLinux 9, including post‑migration checks and common pitfalls.
This guide walks through preparing two CentOS 7.9 servers, installing Docker and Kubernetes 1.19 components, initializing a master node, joining a worker node, and validating the cluster with a sample Nginx deployment, including common troubleshooting tips.
This guide explains why the default CentOS 7 YUM repositories are slow for Chinese users and provides step‑by‑step instructions—including backing up existing .repo files, downloading Alibaba Cloud mirrors, adjusting version numbers, refreshing the cache, verifying updates, troubleshooting common errors, and advanced tips such as adding EPEL—so you can achieve faster, more reliable package management.
This guide explains what NFS (Network File System) is, its advantages, required packages, configuration file syntax, export options, essential tools like rpcinfo, exportfs, showmount and mount.nfs, and provides step‑by‑step examples for mounting, fstab entries, and integrating autofs on CentOS systems.
This article explains the Linux boot sequence, covering the BIOS/UEFI hardware check, GRUB2 bootloader configuration, kernel loading with initramfs, root filesystem mounting, systemd target units, essential services, and a CentOS 8 example with GRUB settings and module inspection.
This guide walks through Linux's startup sequence, covering the BIOS/UEFI hardware check, GRUB2 bootloader configuration, kernel loading, initramfs handling, systemd target units, service initialization, and a concrete CentOS 8 example with command snippets and configuration files.
This tutorial walks through installing Bind on CentOS 8, disabling SELinux and the firewall, configuring /etc/named.conf and zone files for the test.com domain, setting proper permissions, enabling the named service, and verifying DNS resolution.
This guide walks you through installing Certbot, obtaining a free DV SSL certificate from Let’s Encrypt, configuring Nginx for HTTPS, and setting up automatic renewal so your website stays securely encrypted without the hassle of paid certificates.
This article explains OpenSSL’s origins, its role in encryption on CentOS, common use cases such as web servers and database security, provides step‑by‑step installation and upgrade commands, and demonstrates how to generate RSA, SM2, AES, and SM4 keys via the OpenSSL command line and Java alternatives.
This guide walks through analyzing RabbitMQ requirements, selecting self‑hosted servers, preparing CentOS nodes, installing Docker and Docker‑Compose, configuring RabbitMQ, deploying a three‑node high‑availability cluster, and validating its performance and memory usage.
This tutorial walks you through installing ocserv on CentOS, creating a CA and server certificates, configuring routing groups and ocserv.conf, setting up sysctl and iptables firewall rules, managing VPN users, and controlling the service with occtl commands.
This guide explains DHCP fundamentals, its four‑step lease process, allocation methods, advantages, and provides a step‑by‑step tutorial for installing and configuring a DHCP server on CentOS 6.5, including client testing and static host assignments.
This step‑by‑step guide shows how to set up a full LNMP stack, compile and configure Zabbix server, proxy, and agents on CentOS 7, covering repository setup, service initialization, database preparation, UI initialization, and host registration for a robust distributed monitoring solution.
This tutorial walks through installing and configuring the Bind DNS service on a CentOS 8.3 virtual machine, covering environment preparation, SELinux and firewall settings, main and zone file configuration, and how to start and verify the DNS server.
This guide walks you through using firewalld on CentOS 7, covering status checks, starting and restarting the service, configuring zones, managing ports and sources, applying rich rules, and persisting changes, while providing clear command examples for each step.
This guide explains how to locate Linux network‑script files, edit the interface configuration to use DHCP or a static address, and restart the network service, with example commands and screenshots illustrating virtual machine network settings and dynamic IP acquisition.
This article explains DHCP fundamentals, its four‑stage broadcast workflow, allocation methods and advantages, then provides a complete CentOS 6.5 environment setup with commands, configuration file edits, and client testing to help you deploy a DHCP server efficiently.
This article reviews seven viable replacements for the discontinued CentOS 8, comparing AlmaLinux, Ubuntu/Debian, Oracle Linux, OpenSUSE, Rocky Linux, VzLinux, and Springdale Linux, and offers guidance on selecting the most suitable server operating system for 2025.
This guide explains how to configure Hyper‑V's virtual switch manager, choose the Default Switch (internal NAT), and set static IP, gateway, netmask, and DNS inside a CentOS 7.9 VM so that it can communicate with the host and external networks.
With CentOS 8 reaching end‑of‑life, this guide reviews seven viable server‑grade Linux replacements for 2025—including AlmaLinux, Ubuntu/Debian, Oracle Linux, OpenSUSE, Rocky Linux, VzLinux, and Springdale—detailing their compatibility, support cycles, package managers, and migration considerations.
A Spring Boot application on CentOS 6.x hung while fetching Apollo configuration because a single /etc/hosts entry listed dozens of domain names, causing hostname resolution to fail; splitting the entry into multiple lines restored normal startup and highlighted a kernel‑specific hosts parsing bug.
This tutorial walks through preparing three CentOS 7 hosts, installing Docker, configuring kubeadm, initializing a Kubernetes master, troubleshooting common errors, adding worker nodes, installing a CNI plugin, testing the cluster with an Nginx deployment, and provides essential kubectl commands for ongoing management.
This guide walks through checking the current kernel, adding the ELRepo repository, listing available kernels, installing the latest long‑term 5.4 kernel on CentOS 7, setting it as default, removing old kernels, and verifying the upgrade after reboot.
This guide walks through CentOS7 network configuration, explaining interface naming conventions, using NetworkManager tools like nmcli, editing ifcfg files, changing hostnames, renaming interfaces to eth0, adding kernel parameters, and applying changes with service restarts.
This tutorial walks you through checking the current OpenSSH version, installing prerequisite packages, backing up existing SSH files, compiling and installing OpenSSH 8.4p1, verifying the configuration, restarting the service, and confirming the upgrade on a CentOS 7 server.
With CentOS 8 reaching end‑of‑life, this guide reviews seven viable replacements—AlmaLinux, Ubuntu/Debian, Oracle Linux, openSUSE, Rocky Linux, VzLinux, and Springdale Linux—detailing their compatibility, support, and migration considerations to help administrators select the right server OS for 2025.
This guide explains where Linux network‑interface configuration files are stored, how to list and edit them, and the steps for setting up virtual machine networking and dynamic IP addresses, illustrated with command examples and screenshots.
Learn how to use Hyper‑V’s Virtual Switch Manager to create and configure internal (NAT) virtual switches, set up vEthernet adapters, and manually configure static IP, gateway, and DNS on a CentOS 7.9 VM so it gains network connectivity.
This tutorial provides a step‑by‑step guide to set up a fully automated CI/CD pipeline on CentOS 7 that installs Docker, deploys Jenkins in a container, configures Maven and required plugins, creates a Jenkins job, builds a Spring Boot application with Dockerfile, and runs the resulting container, all with minimal pitfalls.
This guide walks through CentOS 7 network setup, explaining interface naming conventions, using NetworkManager tools like nmcli and nmtui, editing configuration files, renaming interfaces, adjusting kernel parameters, and applying changes to achieve reliable connectivity.
This guide explains mounting USB storage, checking device status, configuring NTFS support, and creating, enabling, and disabling swap partitions or swap files on Linux, including practical commands and configuration steps for Ubuntu and CentOS.
Learn how to configure network interfaces on CentOS 7 using NetworkManager tools like nmcli, nmtui, and nm-connection-editor, rename devices, edit configuration files, and apply changes via systemctl, covering both command‑line and graphical methods for effective Linux network management.
This guide walks through installing software on CentOS using source tarballs, RPM packages, and yum, covering terminology, step‑by‑step commands, and practical examples with Redis, RabbitMQ, and Nginx.
This tutorial walks you through installing Samba on CentOS, creating Samba users, configuring a shared directory, editing the smb.conf file, starting services, and finally setting up a client to connect and mount the share, complete with command examples.
With CentOS reaching end‑of‑life, this guide compares four stable, community‑backed Linux distributions—Rocky Linux, Ubuntu, Debian, and AlmaLinux—highlighting their origins, compatibility with RHEL, key features, and suitability as reliable replacements for production servers.
This guide walks through deploying a PostgreSQL instance with the PostGIS extension on a CentOS server using Docker Compose, covering image retrieval, docker‑compose configuration, environment variables, logging settings, container startup, and verification of PostGIS integration.
This guide explains Linux network management, covering IP address and routing configuration, interface naming rules, GRUB tweaks for CentOS and Ubuntu, file‑based setups for CentOS 7, Ubuntu 16.04, Ubuntu 18.04+ with netplan, and graphical configuration via NetworkManager, plus service differences.
This guide walks you through installing common backend services on CentOS—building Redis from source, deploying RabbitMQ via RPM, and adding Nginx with YUM—while explaining key concepts like tarballs, RPM metadata, and YUM repository configuration.
This guide shows how to install the nslookup tool on Debian/Ubuntu and CentOS/RHEL systems and provides seven practical usage examples, including querying IP addresses, specifying DNS servers, retrieving specific record types, performing reverse lookups, setting search domains, using the set command, and exiting the interactive mode.
This article traces the origins and evolution of CentOS, explains the shift to CentOS Stream, outlines the end‑of‑life schedule for CentOS Linux 7 and 8, and evaluates a range of alternative Linux distributions and domestic operating systems for enterprises seeking a replacement.
This article explains Linux I/O schedulers, compares the noop, cfq, and deadline algorithms, shows how to view and modify them on CentOS 6/7, and presents benchmark results indicating that the noop scheduler delivers the best performance on SSDs for MySQL workloads.
This guide explains how to create a high‑availability web load‑balancing cluster using Linux Virtual Server (LVS) and Keepalived on CentOS, covering background, terminology, environment setup, detailed configuration steps for master and backup nodes, real‑server preparation, HA testing, and final conclusions.
The article traces CentOS’s evolution from a downstream RHEL clone to the upstream‑focused CentOS Stream, explains the end of CentOS Linux updates, and evaluates a range of alternative distributions—including Ubuntu, Rocky Linux, Oracle Linux, and several Chinese OS projects—to help enterprises choose the most suitable platform for their workloads.
This guide explains how to monitor disk usage on CentOS 7, collect iostat, sar, and pidstat snapshots, troubleshoot at‑daemon issues, and finally use SystemTap’s inodewatch script together with kernel‑devel and debuginfo packages to pinpoint the exact PID that is writing to a specific file.
The article explains that CentOS Linux 8 ceased updates at the end of 2021 and CentOS 7 will reach end‑of‑support on June 30, 2024, describes the shift to CentOS Stream, and outlines several alternative operating systems—including Rocky Linux, Ubuntu, RHEL, and domestic Chinese distributions—providing guidance for enterprises and developers on migration paths.
This guide explains how to enable VLAN tagging on a Linux server, create VLAN interfaces for different subnets, assign IP addresses, and make the configuration persistent on CentOS/RHEL systems using kernel modules, ip commands, and network‑script files.
When multiple CentOS 7 servers in the same rack experience 30‑60 second delays before prompting for an SSH password, the slowdown is usually caused by reverse DNS lookups and GSSAPI authentication, which can be resolved by disabling UseDNS and GSSAPIAuthentication in sshd_config and restarting the service.
This comprehensive tutorial walks developers through preparing the operating system, disabling firewalls and SELinux, setting up users and JVM options, configuring single‑node and multi‑node Elasticsearch clusters, integrating Kibana, and deploying everything via Docker on CentOS with detailed code examples.
This guide walks you through installing Easy‑RSA, generating CA, server and client certificates, configuring OpenVPN, enabling IP forwarding, adjusting firewalls, and setting up client connections on Linux, macOS and Windows, providing a complete end‑to‑end VPN deployment solution.
This guide walks through preparing three CentOS 7 nodes, installing Erlang and RabbitMQ, configuring users and permissions, setting environment variables, enabling the management plugin, synchronizing erlang.cookie, joining nodes in RAM or disc mode, and verifying cluster status via the web UI.
This guide walks through importing a CentOS 7 virtual machine in VMware, configuring network settings (dynamic or static IP), resolving common issues, then installing and configuring JDK 1.8, MySQL 5.7, and Tomcat 8.5, and finally creating systemd services for automatic startup of Java applications.
This guide walks through setting up a CentOS 7 environment, installing Helm, adding the OpenEBS chart repository, deploying the OpenEBS control plane, creating a dedicated PostgreSQL namespace, and configuring persistent storage with a ConfigMap, providing all necessary commands and screenshots.
This guide explains how to use ifconfig to view and modify network interfaces, manage them with ifup/ifdown, and configure CentOS 7 networking through key files such as /etc/sysconfig/network-scripts, plus essential supplementary ip commands and troubleshooting tips for virtual machine MAC address issues.
With the discontinuation of CentOS Linux, this article evaluates four leading replacement operating systems—AlmaLinux, Rocky Linux, Ubuntu, and Debian—based on stability, long‑term support, and compatibility for enterprise environments.
This guide walks through the complete offline installation of FFmpeg on a CentOS server, covering prerequisite libraries (nasm, yasm, x264), verification of gcc and pkg‑config, compilation steps, troubleshooting missing x264, and finally using FFmpeg to pull an RTSP stream and push it to an RTMP server.
This guide explains how to monitor disk usage on a CentOS 7 server, generate periodic snapshots with iostat, sar, and pidstat, schedule them via at, and ultimately locate the exact process writing to a specific file by extracting its inode and tracing it with SystemTap’s inodewatch script, handling kernel‑devel and debuginfo requirements.
After CentOS reaches end‑of‑life, this article reviews several alternative Linux distributions—Debian, Rocky Linux, Oracle Linux, and AlmaLinux—detailing their origins, key features, compatibility, support timelines, and official resources to help you select the right OS for servers or desktops.
A single overly long line in /etc/hosts caused Spring Boot to hang while fetching Apollo configuration on CentOS 6, and splitting the line into shorter entries resolved the issue, highlighting a subtle hosts‑file limitation in older Linux kernels.
This guide demonstrates how to expand a data disk that lacks partitions on a CentOS 7.4 system, covering both ext* and XFS filesystems, using resize2fs and xfs_growfs commands, and verifying the expansion with df -TH.
This tutorial walks you through installing MongoDB on three CentOS 7.9 servers, configuring a replica set with a master and two slaves, creating admin and test users, securing communication with key files, and verifying failover by stopping the primary node, all illustrated with commands and screenshots.
With the end of CentOS Linux, this article reviews four widely‑used, enterprise‑grade Linux distributions—Ubuntu, AlmaLinux, Rocky Linux, and Debian—detailing their origins, features, compatibility with CentOS, and suitability for production environments.
This guide demonstrates how to enlarge a CentOS 7.4 data disk that has only a filesystem (no partitions) after increasing its size in the cloud console, using resize2fs for ext* filesystems and xfs_growfs for XFS, with verification commands.
This guide shows how to enlarge a CentOS 7.4 data disk that has no partitions—originally 5 GB and expanded to 10 GB—by resizing ext4 or XFS filesystems with resize2fs or xfs_growfs and verifying the new capacity with df.
This guide walks you through backing up the /home partition, editing /etc/fstab to prevent boot errors, uninstalling /home, removing its logical volume, and then extending the /root logical volume and filesystem on a CentOS system using LVM tools such as vgdisplay, lvextend, and xfs_growfs.
This guide walks through four practical methods to create a local YUM repository on CentOS—using a Bash script, mounting an ISO image, configuring the official Aliyun mirror, and sharing via an HTTP server—complete with commands, configuration files, and troubleshooting tips.
This guide explains four ways to create a local YUM repository on CentOS 7—using a Bash script, mounting an ISO image, configuring the official Aliyun mirror, and sharing the repository over a LAN with httpd—complete with commands, configuration files, and troubleshooting tips.
This tutorial walks through preparing a CentOS 8 server, uninstalling any existing Docker packages, adding a Tencent Cloud mirror, installing and starting Docker, configuring a non‑root Docker user group, and finally pulling, configuring, and running an Nginx container with essential HTTPS settings.
This step‑by‑step tutorial shows how to set up a Kubernetes v1.18.8 cluster on CentOS 8.5 running in Hyper‑V, configure static IPs, unique host and machine IDs, install Docker, kubeadm, kubelet and kubectl, deploy flannel networking, the Kubernetes Dashboard, Metrics Server, Helm, and an NGINX Ingress controller, and includes troubleshooting tips.
This guide explains why manual log review is tedious, introduces Logwatch as an automated solution, walks through installing it on CentOS, configuring its core settings, running it manually, and interpreting its concise email reports to simplify Linux system log management.
This guide explains why manual log inspection is tedious, introduces Logwatch as a solution, and provides step‑by‑step commands to install it on CentOS, configure its settings, run analyses instantly, and interpret the generated reports.
This article provides a comprehensive comparison between CentOS and Ubuntu, covering their histories, advantages, disadvantages, package management systems, software repositories, community support, and typical use cases, to help readers choose the most suitable Linux distribution for server or desktop environments.
This article traces the evolution of CentOS within the Linux ecosystem, explains the shift to CentOS Stream, outlines the end‑of‑life schedule, and evaluates various replacement distributions—including Rocky Linux, Ubuntu, Oracle Linux, and several Chinese OS projects—providing guidance for different enterprise and development scenarios.
The article analyzes why a Java service repeatedly crashes around midnight in test environments, tracing the issue through system limits, Java version checks, cron job execution, strace logs, and Linux OOM killer behavior, and finally proposes configuration and version upgrades to prevent the failures.
This article explains what Firewalld is, outlines its key features such as zones, runtime versus permanent settings, services, and dynamic updates, and provides step‑by‑step commands to create firewall rules that limit access to an Nginx server on port 8088 to a single IP address while leaving other ports unrestricted.
This article explains the concepts and advantages of NoSQL databases, categorizes the four main types, introduces MongoDB’s data model and components, and provides step‑by‑step instructions for installing MongoDB 7.0 on CentOS 7 using both yum repository and manual RPM packages.
