Linux Chamber

Systemd is a system and service manager for Linux operating systems. It is designed to be backwards compatible with SysV init scripts, and provides a number of features such as parallel startup of system services at boot time, on-demand activation of daemons, support for system state snapshots, or dependency-based service control logic. It may refer to all the packages, utilities and libraries around daemon. Systemd was designed to overcome the shortcomings of init and itself is a background processes which is designed to start processes in parallel, thus reducing the boot time and computational overhead. It has a lot other features as compared to init. Why there was a need to replace init? A init process starts serially i.e., one task starts only after the last task startup was successful and it was loaded in the memory. This often resulted into delayed and long booting time. However, systemd was not designed for speed but for getting the things done neatly wh

Here are the simple steps for the installation of pssh on CentOS7: pssh is a program for executing ssh in parallel on a number of hosts. It provides features such as sending input to all of the processes, passing a password to ssh, saving output to files, and timing out. Install epel: # yum install epel-release Install pssh: # yum install pssh create pssh_hosts.txt file and enter the hosts need to target: # cat pssh_hosts.txt # write hosts per line like follows #user@target_ip root@192.168.100.100 we should do key-pair between the master host and targets, this is the only way to get things done.(simply login the target from master node for Host key verification) # ssh root@192.168.100.100 Test with single commands # pssh -h /path/to/pssh_hosts.txt -A -O PreferredAuthentications=password -i "hostname" # pssh -h /path/to/pssh_hosts.txt -A -O PreferredAuthentications=password -i "uptime" Output: [root@mas