PSSH

PSSH, short for Parallel SSH, is a suite of open-source tools and a Python library designed to run commands on multiple remote hosts concurrently over SSH. It is used to simplify administrative tasks across large sets of servers, network devices, or other machines reachable via SSH.

The core components include command-line utilities such as pssh for executing a command on many hosts, pscp for parallel file copying, and prsync for parallel synchronization. The tools operate with an inventory of target hosts, provided either as a text file or through a Python API, and allow specifying a user, port, and authentication method. They are designed to work with conventional SSH setups, including key-based and password-based authentication.

During execution, PSSH establishes parallel SSH connections to the listed hosts and runs the specified command or transfers files. It collects standard output and error from each host and supports a range of features to control behavior, such as limiting concurrent jobs, setting timeouts, grouping hosts, and handling failures according to user preferences. The library and tools are suitable for inclusion in scripts and automation workflows.

Usage scenarios include running the same command across all hosts in an inventory, automating deployment tasks, performing health checks, or synchronizing files in parallel. The parallel-SSH ecosystem is widely adopted in DevOps and system administration for managing fleets of machines efficiently, reducing the time required to complete repetitive operations.

See also: SSH, parallel execution, remote command execution, inventory management.