CentOS – nixCraft

userdel: user vivek is currently used by process 749 error and fix on Linux

September 22, 2017in CentOS, Debian / Ubuntu, Linux, Suse, User Management last updated September 22, 2017

I am trying to delete a user named vivek using the userdel command as follows

userdel -r vivek
userdel: user vivek is currently used by process 749

How do I fix this problem and delete username vivek on a Debian Linux 9.x server?

How to shutdown / reboot the remote Linux server from the CLI

August 7, 2017in CentOS, Debian / Ubuntu, Linux, RedHat and Friends, Suse last updated August 7, 2017

I am a new Linux sysadmin. How do I remotely shutdown or reboot the server from the CLI?

How to add new brick to replicated GlusterFS volume on Linux

July 25, 2017July 26, 2017in CentOS, Debian / Ubuntu, Linux, RedHat and Friends last updated July 26, 2017

I have a three server replicated volume setup (scalable network filesystem for cloud and VMs). I need to add one more server. How do I add a new a new brick to an existing replicated volume on a Debian or Ubuntu/CentOS Linux?

How to test the network speed/throughput between two Linux servers

July 25, 2017July 25, 2017in CentOS, Debian / Ubuntu, Linux last updated July 25, 2017

I have setup total four servers in cloud based data center. They run either CentOS or Ubuntu Linux. I need to make sure clustered file system performance is reasonable as my servers shared with other users. How do I check the speed between the two Linux servers using command line options for private LAN/VLAN?

How to upgrade LXD VMs powered by Ubuntu/Debian or CentOS Linux

July 11, 2017in BASH Shell, CentOS, Debian / Ubuntu, Linux, Linux Containers (LXC) last updated July 11, 2017

I run over 10+ LXD VMs powered by CentOS Linux 7 and Debian/Ubuntu Linux. How do I upgrade all VMs automatically or on demand using Ansible tool?

How to use or specify multiple IP addresses in iptables source or destination on Linux

June 29, 2017in CentOS, Debian / Ubuntu, Iptables, Linux, RedHat and Friends, Suse last updated June 29, 2017

I need to specific multiple IP address in iptables using Linux script. How do I create a rule that uses multiple source or destination IP addresses ?

How to install latest kernel on CentOS Linux 7 using yum command

June 25, 2017June 25, 2017in CentOS, Linux, Package Management last updated June 25, 2017

I am a new CentOS Linux 7 user who runs it on my Laptop. I liked the operating system. Is there is a way to run latest/stable Linux kernel on a CentOS Linux version 7?