Master Parallel SSH: Install, Use, and Extend the pssh Tool Suite

parallel-ssh is an asynchronous, parallel SSH library designed for small‑scale automation, providing tools such as pssh, pscp, prsync, pslurp, and pnuke. Originally hosted on Google Code and maintained by Brent N. Chun, the project was handed to Andrew McNabb in 2009 and later archived when Google Code shut down.

Earlier releases did not support Python 3, but a GitHub fork adds Python 3 compatibility, and an organization has also attempted maintenance, though it has not been updated recently. Relevant repositories include:

https://github.com/lilydjwg/pssh

https://github.com/ParallelSSH/parallel-ssh

Scalability : Can manage hundreds to thousands of hosts.

Ease of use : Only two lines of code are needed to run commands on any number of machines.

Performance : Claimed to be the fastest available Python SSH library.

Resource efficiency : Consumes less resources than alternative Python SSH libraries.

# Mac installation
$ brew install pssh
# CentOS installation
$ yum install pssh
# Ubuntu installation
$ apt install pssh
# Pip installation
$ pip install pssh
# Source compilation (2.3.1)
$ tar zxvf pssh-2.3.1.tar.gz
$ cd pssh-2.3.1
$ python setup.py install

The installed binaries include:

# List installed tools
$ ls -lh /usr/local/Cellar/pssh/2.3.1_1/bin/
pnuke -> ../libexec/bin/pnuke
prsync -> ../libexec/bin/prsync
pscp -> ../libexec/bin/pscp
pslurp -> ../libexec/bin/pslurp
pssh -> ../libexec/bin/pssh
pssh-askpass -> ../libexec/bin/pssh-askpass

pssh

Runs commands in parallel on multiple hosts via SSH.

# Usage: pssh [OPTIONS] command ...
# Run on two hosts and print output
pssh -i -H "host1 host2" hostname -i
# Save output to separate files
pssh -H host1 -H host2 -o /path/to/output_dir hostname -i
# Use a hosts file
pssh -i -h /path/to/hosts_file hostname -i
# Run as root (prompt for password)
pssh -i -h /path/to/hosts_file -A -l root_user hostname -i
# Pass extra SSH options
pssh -i -h /path/to/hosts_file -x "-O VisualHostKey=yes" hostname -i
# Limit parallel connections to 10
pssh -i -h /path/to/hosts_file -p 10 'cd dir; ./script.sh; exit'

pscp

Copies files in parallel to multiple hosts via SSH.

# Usage: pscp [OPTIONS] local remote
# Copy local file to remote machines
pscp -h hosts.txt -l root foo.txt /home/irb2/foo.txt

prsync

Efficiently copies files in parallel to multiple hosts using rsync.

# Usage: prsync [OPTIONS] local remote
prsync -r -h hosts.txt -l root foo /home/irb2/foo

pslurp

Copies files from multiple remote hosts to a central host via SSH.

# Usage: pslurp [OPTIONS] remote local
pslurp -h hosts.txt -l root -L /tmp/outdir /home/irb2/foo.txt foo.txt

pnuke

Kills processes matching a pattern on multiple remote hosts via SSH.

# Usage: pnuke [OPTIONS] pattern
pnuke -h hosts.txt -l root java