Parallel SSH is a useful tool designed to run a command on multiple servers in parallel. An advantage of PSSH over some alternatives (like DSH) is the manner outputs are stored: all outputs are sent to a folder containing an output file per server.
First create your servers list, using the syntax
host:port user :
vi /tmp/hosts_list.txt server1 server2 server3:2222 foobar
Then create two directories: one for standard outputs, the second for error outputs.
mkdir /tmp/output mkdir /tmp/error
Then execute your command:
parallel-ssh -h /tmp/hosts_list.txt -o /tmp/output/ -e /tmp/error/ uptime
Further Reading and sources