How to use parallel
#ssh (#PSSH) for executing commands in parallel on a number of Linux/Unix/BSD servers
https://www.cyberciti.biz/cloud-computing/how-to-use-pssh-parallel-ssh-program-on-linux-unix/How to use parallel ssh (PSSH) for executing commands in parallel on a number of Linux/Unix/BSD servers - nixCraft
Explains how to install and use parallel ssh (PSSH) tool for executing ssh in parallel on a number of hosts and automate many IT tasks.
Mac