OpenSSH : Use Parallel SSH

	Install Parallel SSH to connect to multiple hosts.
[1]	Install PSSH.

root@dlp:~#  apt -y install pssh

[2]	This is the basic usage for PSSH. This is the case for key-pair authentication without passphrase. If passphrase is set in key-pair, start SSH-Agent first to automate inputting passphrase.

# connect to hosts and execute [hostname] command debian@dlp:~$  parallel-ssh -H "10.0.0.51 10.0.0.52" -i "hostname" [1] 09:51:46 [SUCCESS] 10.0.0.51 node01.srv.world [2] 09:51:46 [SUCCESS] 10.0.0.52 node02.srv.world # it's possible to read host list from a file debian@dlp:~$  vi pssh_hosts.txt # write hosts per line like follows debian@10.0.0.51 debian@10.0.0.52 debian@dlp:~$  parallel-ssh -h pssh_hosts.txt -i "uptime" [1] 09:52:28 [SUCCESS] debian@10.0.0.51 09:52:28 up 12 min, 2 users, load average: 0.00, 0.00, 0.00 [2] 09:52:28 [SUCCESS] debian@10.0.0.52 09:52:28 up 2 min, 1 user, load average: 0.00, 0.00, 0.00

[3]	It's possible to connect with password authentication too, but it needs passwords on all hosts are the same one.

debian@dlp:~$  parallel-ssh -h pssh_hosts.txt -A -O PreferredAuthentications=password -i "uname -r" Warning: do not enter your password if anyone else has superuser privileges or access to your account. Password: # input password [1] 09:53:03 [SUCCESS] debian@10.0.0.51 6.12.38+deb13-amd64 [2] 09:53:03 [SUCCESS] debian@10.0.0.52 6.12.38+deb13-amd64

[4]	By the way, PSSH package includes [parallel-scp], [parallel-rsync], [parallel-slurp], [parallel-nuke] commands and you can use them with the same usage of pssh.