Tag: CentOS

Rescue a CentOS system with GRUB

GRUB (Grand Unified Bootloader)  is the most widely used bootloader among Linux operating systems (OS) but it can boot any OS. GRUB main functionality is to allow users to select between different operating systems to boot. As bootloader GRUB is installed on the MBR (Master Boot Record) and additionally to allow us to select different …

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Inspecting and extracting RPM package contents

This article will cover basics of the RPM package architecture and show how we can see RPM package content and extract it. There will be examples how to extract RPM package files from Linux command line. An RPM package is simply a header structure on top of a CPIO archive. The package itself is comprised …

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Disk Encryption on CentOS using LUKS Cryptsetup

luks-linux-disk-encryption

LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it does not only facilitate compatibility among distributions, but also provides secure management of multiple user passwords. In contrast to existing solution, LUKS stores all setup necessary setup information in the partition header, enabling the user to …

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10 Practical Sar Usage Examples

There are two ways to invoke sar. sar followed by an option (without specifying a saXX data file). This will look for the current day’s saXX data file and report the performance data that was recorded until that point for the current day. sar followed by an option, and additionally specifying a saXX data file …

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Generate CPU, Memory and I/O report using SAR command

SAR stands for System Activity Report, as its name suggest sar command is used to collect,report & save CPU, Memory, I/O usage in Unix like operating system. SAR command produce the reports on the fly and can also save the reports in the log files as well. In this article we will discuss different examples …

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How to Install and Configure GitLab on CentOS 7

gitlab

Gitlab is an open source, powerful, robust, scalable, secure, as well as efficient software development and collaboration platform for all stages of the DevOps lifecycle. It allows you to plan your development process; code, and verify; package software, and release it with an in-built continuous delivery feature; automate configurations management, and monitor software performance. It …

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How to Install PHP 7 in CentOS 7

The CentOS 7 official software repositories have PHP 5.4 that is reached end of life and no longer actively maintained by the developers. Thus you need a newer PHP 7 on your CentOS server. The commands below will help you install PHP 7 on CentOS. All of them are executed as root account or with …

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Fail2ban installation and configuration on CentOS

In this article I’ll describe how to protect Asterisk from hacking attempts with Fail2ban in CentOS Linux. Fail2Ban is a standard Linux tool used to scan log files and then block IP’s found in those log files using iptables. Fail2ban depends completely on the application (in this case Asterisk) to detect any intrusion/failure and log …

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Enable Apache event MPM with php-fpm

Choose-Apache-MPM-Module

Starting from version 2.4 Apache offers 3 MPM (Multi-processing Module) we can choose from, depending on your needs. The prefork MPM uses multiple child processes without threading. Each process handles one connection at a time without creating separate threads for each. Without going into too much detail, we can say that you will want to …

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How To Configure Firewall on CentOS 7

FireSince CentOS 7 Firewalld is available by default on servers as a complete firewall solution. This guide will cover the basics of configuration and management using firewall-cmd administrative tool (if you’d rather use iptables with CentOS, follow this guide).

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