27 nmcli command examples (cheatsheet), compare nm-settings with if-cfg file

7 ways to prevent brute force SSH attacks in Linux (CentOS/RHEL 7)

A brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct one is found. In this ar

2 ways to backup and restore partition table in Linux (CentOS / RHEL 7)

In my last article I gave you an overview on Public key Infrastructure (PKI) and shared the steps to generate a self signed certificate using openssl in Linux. Next let me show you the steps to copy partition table from one disk to another or backup

Basics OpenLDAP Tutorial for Beginners – Understanding Terminologies & Usage

This is a multi-part article where I will cover different areas of configuration of OpenLDAP server in CentOS 7 Linux node. You can use below links to refer different parts of this tutorialBasics LDAP Tutorial for Beginners – Understanding Termin...

How to improve disk IO performance in Linux

In my last article I gave an overview on SystemTap to help you trace and debug kernel modules, Now here before we understand on how to improve disk IO performance, we should understand the basics of IO flow in the Linux environment. &nbs

Difference between /dev/tty and /dev/pts (tty vs pts) in Linux

What is the difference between /dev/pts and /dev/tty. What is /dev/tty and /dev/pts. Why do I get /d...

6 commands to check and list active SSH connections in Linux

How to check active SSH connections in Linux. Show SSH connection history. How to show active ssh se...

How to restrict or allow ssh only from certain users, groups or hosts in Linux

How to configure SSH to permit root login only from specific host or IP address? How to configure SS

How to revoke the certificate and generate a CRL with openssl

I would recommend you to get an overview of PKI and Certificates before generating or revoking certi

Cinder vs Swift storage in OpenStack – Basic Difference and Comparison

Earlier I had shared an article with the steps to configure ceph storage cluster in OpenStack. Now l

OpenStack Command Line Cheat Sheet (Beginner’s Guide)

In this article I will share some of the basic OpenStack command line cheat sheet which can be usefu

How to configure or build ceph storage cluster in Openstack ( CentOS 7 )

In my last article I shared the steps to configure controller node in OpenStack manually, now in thi

Steps to Install and configure Controller Node in OpenStack – Part 2

This is the second and the final part of the steps to Install and configure controller node in OpenS...

Configure xfs quota (user, group and project quota) CentOS/RHEL 7/8

centos 7 xfs enable quota. centos 7 quota xfs. how to configure xfs quota in rhel/centos 7 and 8. user quota in linux step by step. change grace perio...

27 nmcli command examples (cheatsheet), compare nm-settings with if-cfg file

nmcli examples. nmcli cheatsheet in CentOS/RHEL 7/8. nmcli command exmaples. nmcli con reload. nmcli help. add ethernet connection using nmcli. nmclic...

How to create and configure network bridge using nmcli (static & dhcp)

nmcli bridge. nmcli restart network. nmcli reload. nmcli configure network bridge in RHEL. create network bridge using nmcli. configure network bridge...

4 commands to check threads per process (threads vs processes)

In Linux, some processes are divided into pieces called threads. In one liner, threads are essentially just processes with a shared address space on L

install multi node openstack on viirtualbox using centos7

How to install multi node openstack on virtualbox with packstack on CentOS 7

In this article I will share the steps to install multi node OpenStack on VirtualBox using CentOS 7 Linux. Packstack is used to perform multi node Ope...

How to configure port forwarding in VirtualBox for NAT Networking

configure port forwarding in virtualbox command line. virtualbox port forwarding to host. virtualbox port forwarding range. vmware port forwarding. vi...

Bridged vs Internal vs NAT vs NAT Network vs Host Only Network - Oracle VirtualBox - Part 1

Bridged vs Internal vs NAT vs NAT Network vs Host Only Network - Oracle VirtualBox - Part 2

Configure BIND-9.8 DNS Server in Red Hat Linux 6