Keepalived is a daemon that provides simple and robust facilities for load balancing and high-availability to Linux based infrastructures. It uses the VRRP (Virtual Router Redundancy Protocol) protocol to provide a highly available IP address to be used as a default gateway by clients. If the primary node goes down, Keepalived will automatically transfer the … Read more
In UNIX and Linux, file permissions are defined by three sets of permissions for three types of users: the owner, the group, and others. These permissions are read (r), write (w), and execute (x). In addition to these basic permissions, there is a special type of file permission called setuid (short for “set user ID”). … Read more
To install and configure Nginx as a reverse proxy and load balancer on CentOS or Red Hat, you can follow these steps: Install the EPEL repository if it is not already installed on your system. EPEL provides additional packages that are not available in the official CentOS or Red Hat repositories. You can install it … Read more
There are several UNIX command line tools available for Windows operating systems, including: Cygwin: Cygwin is a Linux-like environment for Windows that provides a collection of tools and utilities, including shells, compilers, editors, and other development tools. It offers a UNIX-like environment on Windows, allowing users to run many UNIX commands and utilities natively. Windows … Read more
Keepalived is a free, open-source software package that provides failover and load-balancing services for Linux-based systems. It is commonly used to manage web servers and proxies, including nginx. In this example, we will set up a failover cluster with two nginx servers, one acting as the master and the other as a backup. Here are … Read more
To convert tabs to spaces in a file using a Bash shell, you can use the expand command. Here’s how to do it: Open a terminal and navigate to the directory where the file is located. Run the expand command followed by the name of the file you want to convert. For example, if your … Read more
In Linux, you can create a RAM disk, also known as a RAM filesystem or a tmpfs, which is a portion of your system’s memory that is used as a virtual disk. This can be useful for storing temporary files, speeding up disk-intensive operations, and reducing wear on physical disks. Here’s how to create a … Read more
To install the Linux kernel headers and development files on a Fedora Linux system, you can use the dnf package manager. Here’s how to do it: Open a terminal and update the dnf package manager’s cache by running the following command: sudo dnf makecache Install the kernel headers and development files by running the following … Read more
To list the files contained in an RPM package, you can use the rpm command with the -ql option. Here’s how to do it: Open a terminal and run the following command to list the files contained in an RPM package: rpm -ql package-name Replace package-name with the name of the RPM package that you … Read more
To create a bootable USB pen drive in Linux, you can use the dd command to write the ISO image to the USB drive. Here’s how to do it: Insert the USB pen drive into a USB port on your computer. Open a terminal and type the following command to find the device name of … Read more