mussh

mussh -H hosts.txt -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i .ssh/id_uk_rsa -s /bin/sh -C script_exec_cliente1
parallel-ssh -v -i -l root -e result -o result -h hosts.txt -O UserKnownHostsFile=/dev/null -O StrictHostKeyChecking=no -O IdentityFile=.ssh/id_uk_rsa uptime

http://www.softpanorama.org/Admin/parallel_command_execution.shtml