Saturday, 17 December 2022

How to Install Open VMware Tools on CentOS 8



VMware Tools are very important role plays when working with VMware Player, VMware Workstation Pro, VMware ESXi or vSphere. If VMware Tools are installed on a guest, it will report back to the VMware hypervisor guest’s IP address, CPU usage, disk usage, memory usage etc. Installing VMware Tools on a Linux machine requires a few extra steps compared to Windows. RPM based installation performed on CentOS 8 and related packages are available in its default’s repository.

Wednesday, 14 December 2022

How to Install/Reinstall ssl on CentOS 7



openssl is a base package of ssl binaries and available in default repository CentOS 7 minimal installation. If removed by accident or broken, the package can be installed or reinstalled again using yum. openssl is an essential tool of any Linux distributions to work with various certificates.

Tuesday, 29 November 2022

How to Install Open VMware Tools on CentOS 7



VMware Tools are very important role plays when working with VMware Player, VMware Workstation Pro, VMware ESXi or vSphere. If VMware Tools are installed on a guest, it will report back the guest information to the VMware hypervisor like guest’s IP address, CPU usage, disk usage, memory usage etc. Installing VMware Tools on a Linux machine quit easy. In this article, RPM based installation performed on CentOS 7 and related packages are available in its defaults repository.

Tuesday, 15 November 2022

How to Fix – ‘Error: Unable to find a match: iperf’ on CentOS 8



Mostly the above message through the system when its package or binary not available on CentOS 8 default repositories. Its binary not available in CentOS 8  BaseOS and AppSteam repositories but it can be installed from EPEL Repository. 

Monday, 14 November 2022

How to Fix – ‘ifconfig Command Not Found’ on CentOS 8



The network command line tool ‘ifconfig’ is not available on CentOS 8 minimal installation. Ifconfig command is part of net-tools package and it can be installed from CentOS 8 default BaseOS repository on CentOS 8

Friday, 11 November 2022

How to Maintain Specific Number of Kernel Packages on CentOS 8



Sometime due to less space on /boot partition need remove old kernel packages once new/updated kernel installed. The “installonly_limit” option in /etc/dnf/dnf.conf is used to maintain the number of kernel available. By default, the limit is set to 3 kernels in CentOS 8.

Wednesday, 9 November 2022

How to Change Machine ID after Cloning a VM on CentOS 7



A Machine ID is a unique hexadecimal, 32-character, lowercase code of the local system that is set during installation and represents an individual machine ID over the network.

Thursday, 3 November 2022

How to Install KSH (Korn Shell) Shell on CentOS 8



KSH (Korn Shell) is a shell programming language, which is upward compatible with 'sh' (Bourne Shell). KSH was developed by David Korn at Bell Labs in 1980s. KSH is quite popular and used by most of the Linux System Admins to automate daily tasks on Linux/Unix like operating systems. You can install ksh on CentOS 8 using its AppSteam repository.

How to Configure Local YUM repository on CentOS 8 using Installation ISO Image



YUM (YellowDog Updater Modified) is a package management tool for RPM based Linux system that helps to install, uninstall, and update packages local and other client machines over the network. YUM resolve all dependency and install the package with all dependencies. CentOS 8 has two repositories BaseOS and AppStream and they are different from each other. BaseOS repository provides packages which are useful for an operating system and AppStream provides software packages such as databases and dependencies.

Wednesday, 2 November 2022

How to Install SNMP Tool on CentOS 7



Monitor Routers, Firewalls and Linux Servers agentless, with the support of SNMP (Simple Network Management Protocol) tool. It is an internet protocol that can retrieve the operational statistics from the devices remotely. Its binary available in CentOS 7.

Friday, 21 October 2022

How to find WWN Name of a QLogic Card on CentOS 7



CentOS 7 community provides a utility systool to work with hardware adapters. The utility comes with sysfsutils package and this package by default not installed on  CentOS 7 systems. 

How to resolve “-bash: systool: command not found” on CentOS 7



CentOS 7 community provides a utility systool to work with hardware adapters. The utility comes with sysfsutils package and this package by default not installed on  CentOS 7 systems.

Thursday, 13 October 2022

How to Maintain Specific Number of Kernel Packages on CentOS 7



Sometime due to less space on /boot partition need remove old kernel packages once new/updated kernel installed. The “installonly_limit” option in /etc/yum.conf is used to maintain the number of kernel available. By default the limit is set to 3 kernels in CentOS 7. 

Friday, 7 October 2022

How to Install GlusterFS on CentOS 7



GlusterFS packages are not included in the default CentOS 7 repository so the packages can be installed from Gluster repository and EPEL repository. GlusterFS packages needs to install on all the GlusterFS Nodes.

Saturday, 16 July 2022

How to Resolve YUM Repo Mirror URLs List Issue on CentOS 8



Sometime mirror URLs does not work on CentOS 8 systems and gives the below error. To solve the yum repo issue need to replace it with base URLs.

Friday, 8 July 2022

How to Install Grafana Beta Monitoring tool on CentOS 7



Grafana is a power full software for real time system data monitoring also generate graph and dashboard for easy understanding. It is available in community and enterprise editions. Beta release can also installed via its separate repository. 

Wednesday, 6 July 2022

How to Install Grafana 9 Monitoring tool on CentOS 7



Grafana is a power full software for real time system data monitoring also generate graph and dashboard for easy understanding. It is available in community and enterprise editions.

Thursday, 30 June 2022

How to Install Spacewalk Server on CentOS 7



Spacewalk tool is a free and open source Linux operating system management tool for system provisioning and configuration/management/updating tool of its clients. It is a community version of Red Hat Satellite Server and widely used on Red Had derived distributions.

Tuesday, 29 March 2022

How to Enable Networking in Rescue Mode in CentOS 7



Sometimes required network connectivity in rescue mode to take server logs to other server/workstation for further analysis as the networking is not enabled during the initial rescue environment setup.

Sunday, 6 March 2022

How to disable consistent network device naming in CentOS 8



This article describes How to disable consistent network device naming in CentOS 8.

How to Configure Local Synced YUM repository on CentOS 7 using vsFTP



YUM (YellowDog Updater Modified) is a package management tool for RPM based Linux system that helps to install, uninstall, and update packages. Local yum repository is used to save bandwidth, fasten package installations, network installations and systems updates for n numbers of systems in a local area network.

Friday, 4 March 2022

How to Install and Configure Anonymous vsFTP Server on CentOS 7



vsFTP (Very Secure File Transfer Protocol) is a free and open source widely used client-server network protocol that used for transferring files between server and clients over the network.

How to Install FTP Client on CentOS 7



FTP (File Transfer Protocol) is a free and open source widely used client network protocol. It basically used to connect vsFTP server to upload/download files from server to client machine.

Tuesday, 1 March 2022

How to Extend a Logical Volume on CentOS 7



Sometime encountered with no space left on file system error and demand opened to increase file system space. It would be easy if file system is created under LVM.

How to Change or Rename a Regular Mount Point in CentOS 7



Sometimes mount point renaming require on a machine for any user request or any application requirements.

How to Configure Local Synced YUM repository on CentOS 7 using NGINX



YUM (YellowDog Updater Modified) is a package management tool for RPM based Linux system that helps to install, uninstall, and update packages. Local yum repository is used to save bandwidth, fasten package installations, network installations and systems updates for n numbers of systems in a local area network.

Friday, 25 February 2022

How to Allow/Deny Access for AD Users/Groups using Realmd on CentOS 8



Once the Linux machine joined with any Active Directory Domain, all the AD users can get SSH login on the machine with regular user privileges to avoid this access can manage using realm command.

Thursday, 24 February 2022

How to Resolve Slow SSH Login Before Getting Password Prompt on CentOS 8



Sometime SSH login failures encountered with gssapi-with-mic authentication method and hence takes time to get password prompt.

Wednesday, 23 February 2022

How to Allow SUDO Access to a Domain User/Group on CentOS 8



By default, Domain users doesn’t have any type of sudo privilege and even can’t switch as root user. On CentOS 8 sudo access can be granted access based on usernames or groups and same can be done for one/many commands.

Tuesday, 8 February 2022

How to Extend Logical Volume on CentOS 8



Sometime encountered with no space left on file system error and demand opened to increase file system space. It would be easy if file system is created under LVM.

Sunday, 30 January 2022

How to Install tcpdump and use of tcpdump command on CentOS 8



Tcpdump is a command line utility which is widely used to capture packet sniffer or filter TCP/IP packets that received or transferred over the network. it is allowing to analyse headers of TCP/IP which helps in network troubleshooting.

How to Configure Local Synced YUM repository on CentOS 7 using HTTP



YUM (YellowDog Updater Modified) is a package management tool for RPM based Linux system that helps to install, uninstall, and update packages. Local yum repository is used to save bandwidth, fasten package installations, network installations and systems updates for n numbers of systems in a local area network.

Sunday, 16 January 2022

How to Resolve showmount fails with error “clnt_create: RPC: Program not registered “on CentOS 7



NFS share is a network file sharing protocol. It is used to provide shared access to files and folders across Linux machines over the network. This error comes when sometime the NFS service is stopped on the NFS server and will gives the below error while running showmount –e <NFS Server IP>.

Saturday, 15 January 2022

How to Resolve kernel panic at boot with error initrd image file not found on CentOS 7



Sometime after yum update transaction break or kernel update or fresh install, the system fails to find initrd (initial ram disk) and also due to that unable to mount the root file system and also fail to boot the system with below message on CentOS 7 systems:

How to Resolve “kernel panic at boot with error Unable to mount root fs on unknown-block” on CentOS 7



Sometime after yum update transaction break or kernel update or fresh install, the system fails to mount the root file system and also fail to boot the system with below message on CentOS 7 systems:

Wednesday, 12 January 2022

How to Configure Local YUM repository on CentOS 7 using ISO Image



YUM (YellowDog Updater Modified) is a package management tool for RPM based Linux system that helps to install, uninstall, and update packages local and other client machines over the network. YUM resolve all dependency and install the package with all dependencies.

Tuesday, 11 January 2022

How to Install SEmanage on CentOS 8



SEmanage is a command-line utility and provide ability to manage SELinux contexts. Its needs separate installation by default this package is not available in CentOS 8 minimal installations.

How to resolve -bash: showmount: command not found on CentOS 8



showmount command: It is a command-line utility and provide ability to manage NFS share. Its needs separate installation by default this package is not available in CentOS 8 minimal.

How to Resolve wrong fs type while mounting NFS share on CentOS 7



NFS share is a network file sharing protocol. It is used to provide shared access to files and folders across Linux machines over the network. This error comes when the nfs-utils package is missing from the machine and will give the below error while mounting any NFS share point.

Tuesday, 4 January 2022

How to resolve -bash netstat command not found on CentOS 8



Netstat is a command-line utility and provide ability to check open ports whether it is UDP or TCP. Its needs to separate installation by default this package is not available in CentOS 8 minimal.

How to Change the SSH Port on CentOS 8



We can change the default SSH port CentOS 8 as an added security concerns. To Change the SSH Port on CentOS 8 systems connect to server with root privileges.

How to resolve -bash: semanage: command not found on CentOS 8



Semanage command: It is a command-line utility and provide ability to manage SELinux contexts. Its needs to separate installation by default this package is not available in CentOS 8 minimal.

How to Install and Use tcpdump Command on CentOS 8



Tcpdump is a command line packet sniffer/ packet analyser tool which used to capture or filter TCP/IP packets that received or transferred over a network on a specific interface. By default, tcpdump is available under most of Linux distributions but if we have a minimal installation of CentOS 8.

Saturday, 1 January 2022

How to Disable SSH Remote Root Login on CentOS 8



After fresh system installation the Remote root login is enabled by default on the CentOS 8. As recommended, SSH Remote root login must be disabled for security and compliance on production systems.

How to Enable SSH root login on CentOS Stream 9 System



After fresh system installation the root login on the CentOS Stream 9 is disabled by default. When attempt to login as root user to CentOS Stream 9 the access will be denied (access denied).

How to Install CentOS Stream 9 Minimal Step by Step



The CentOS Project is recently released CentOS Stream 9. It is a new community version of RHEL and added many new features for users.