Master Parallel SSH (PSSH): Run Commands, Transfer Files, Sync Servers

PSSH stands for Parallel SSH, allowing a single command to be executed simultaneously on multiple servers, simplifying cluster management.

Example to view load on all servers: pssh -h hostlist -i w where hostlist is a text file listing servers, e.g.:

[email protected]:22
[email protected]:22

PSSH examples

Copy a local file to all servers:

pscp -h hostlist /root/fileA /tmp/fileA

Copy a file from all servers to the local machine:

pslurp -h hostlist -L /tmp/test /home/err_log log

Synchronize a local directory to each server:

prsync -h hostlist -a -r /tmp/test /home

PSSH installation

Download:

https://pypi.python.org/packages/source/p/pssh/pssh-2.3.1.tar.gz

Extract: tar xzvf pssh-2.3.1.tar.gz Install: cd pssh-2.3.1 && python setup.py install Test: pssh --help and run a command, e.g.

pssh -H [email protected] -A -i date

Configure password‑less SSH

Generate a key pair with ssh-keygen (accept defaults), then copy the public key to each server: ssh-copy-id -i /root/.ssh/id_rsa -p 22 [email protected] After copying keys, subsequent pssh commands no longer prompt for a password.

PSSH is lightweight, easy to install, and can dramatically speed up routine server‑administration tasks.