How does sudo remember you already entered root's password?

What is the best way to provide sudo password to a remote machine from a script?

• I am writing a script that basically does "ssh -t name@machine 'sudo reboot'". this script sshs into a bunch of machines and reboots them. is there a way i could pass the sudo password of the machines in the ssh command so that I don't have to manually type password for each 'sudo passwd' command.

• Answer:

  First of all, as Tristan has said, the most secure way of setting this up is to use a passwordless sudo. Nonetheless, you can further harden things by creating a specific user for this task, and then restricting its ssh access so that it can only run this command. Basically, you first create a 'rebooter' user on each of the machines that have to be rebooted, and disable password authentication for them by issuing a 'passwd -l rebooter'. Next, you setup the '/etc/sudoers' file to allow this user to passwordless run '/sbin/reboot' as root, following 's instructions. Finally, in their corresponding '.ssh/authorized_keys' file, you setup the public key like this: from="the.controller.machine",command="/usr/bin/sudo /sbin/reboot" ssh-rsa AAAA(your key's data here)== [email protected] Thereafter, the 'rebooter' user can only connect from 'the.controller.machine', and it can only issue the 'sudo reboot' command. In fact, it will issue the 'sudo reboot' command even if it tries to specify any other command on its side.