CentOS
👉 Overview
👀 What ?
CentOS, or Community Enterprise Operating System, is a free and open-source platform that is functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL). It is designed to provide a robust, scalable and reliable platform for enterprise-class, production-ready computing.
🧐 Why ?
CentOS is widely used due to its enterprise-grade features, long-term support, strong security, and active community. It is commonly used in web servers, network servers and as a base for virtual machines and containers. Understanding CentOS is crucial for anyone working with Linux in an enterprise environment, as it forms the backbone of many IT infrastructures.
⛏️ How ?
To get started with CentOS, you will first need to download the ISO file from the official CentOS website and create a bootable device. From there, you can install the OS on your machine and begin to explore its features. CentOS uses the YUM package manager for software installation and updates. To install a software, you use the command 'yum install [software]', and to update the system, you use 'yum update'.
⏳ When ?
CentOS was first released in 2004 as a free alternative to RHEL. Its usage has grown steadily since then, especially among web hosts and other businesses that rely on stable, secure, and high-performance servers.
⚙️ Technical Explanations
CentOS is a free and open-source operating system, built using the same source code as Red Hat Enterprise Linux (RHEL). Hence, it offers the same functionality, reliability, and security as RHEL, making it a popular choice for enterprise-level computing.
At the core of CentOS is the Linux kernel, which manages the system's interactions with its hardware. This includes tasks like resource management, process scheduling, and input/output requests. The kernel is the fundamental part of the operating system, ensuring that everything runs smoothly and efficiently.
One of the primary ways users interact with CentOS is through the shell or command-line interface. The shell takes in commands from the user and instructs the kernel to perform specific functions based on these commands. This interface allows users to have direct control over the system’s operations.
In addition to the kernel and shell, CentOS comes with an extensive range of pre-compiled software packages. These include server software like Apache or Nginx, programming languages like Python or PHP, and many others. This vast array of software makes CentOS adaptable to many different use cases.
The YUM package manager is another vital aspect of CentOS. It handles the installation, updating, and removal of software packages. YUM also automatically resolves dependencies, meaning it will automatically install any additional software required for a package to function correctly.
Stability and security are two of CentOS's most notable characteristics. Updates to the system are thoroughly tested before release to ensure they don't introduce new bugs or vulnerabilities. Moreover, CentOS is equipped with robust security features. These include SELinux, a security module that provides mechanisms to enforce access control policies, and a built-in firewall to prevent unauthorized access.
In conclusion, CentOS is a robust, secure, and versatile operating system. It is highly suitable for enterprise-level computing due to its compatibility with RHEL, its robust security features, and its comprehensive software package offerings.
Here are some essential commands for CentOS:
yum install [package-name]: Install a software packageyum update: Update all system softwareyum remove [package-name]: Remove a software packagesystemctl start [service]: Start a system servicesystemctl stop [service]: Stop a system servicesystemctl status [service]: Check the status of a system servicefirewall-cmd --add-port=[port-number]/tcp --permanent: Add a TCP port to the firewallfirewall-cmd --reload: Reload the firewall configurationsemanage fcontext -a -t [type] [file/directory]: Change the SELinux context of a file or directoryrestorecon -Rv [file/directory]: Restore the SELinux context of a file or directory