Ssh – Make change to config files on multiple servers using SSH

ssh

Problem:

I'm trying to disable SSH password auth for multiple servers.
Which means I have to modify the sshd_config file.
From

#PasswordAuthentication yes

to 

PasswordAuthentication no

I really don't wanna do it one by one. Is there any ways that I can distribute/modify the config file on multiple servers with a single command?

Assumptions you can make:

  • Those servers have same OS
  • I can broadcast the SSH command to multiple servers at once

Other notes:

I set the config file to listen different address and/or port on each server.

So this could not be done by downloading the updated config file from a central server.

I prefer a text replacement command to do the job

Best Answer

Look into configuration management tools like Puppet, Ansible or cfengine. They are helpful in the long run.

For a one-off, you could use Augeas, that make this change extremly easy, or even sed, which is present on most systems without further installs. 

sed -i s/\#PasswordAuthentication\ yes/PasswordAuthentication\ no/ /etc/ssh/sshd_config

This can be sent in a simple ssh command: 

ssh user@server sed ......
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