execute remote command via ssh passwordlessly (no ssh keys) on many hosts

ssh_cluster.sh

# execute remote command via ssh passwordlessly (no ssh keys) on many hosts
export SSHPASS=my_password  # sshpass will use it

printf "host1\host2\n" | xargs -i sshpass -e ssh your_username@{} 'ls -la'
# or
cat hostlist.txt | xargs -i sshpass -e ssh your_username@{} 'ls -la'

# mass copy ssh public key onto many hosts 
cat hostlist.txt | xargs sshpass -e ssh-copy-id -i ~/.ssh/id_rsa.pub