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I've used yum install nagios on an Amazon Linux instance, and it created a nagios user with shell /sbin/nologin and homedir /var/spool/nagios. This is the behaviour on EC2.

I want to use check_by_ssh running locally as user nagios to execute a command on the remote host as some user, without typing in a password. So using ssh-keygen seems logical, but how do I generate a public key for user nagios if that user doesn't have a shell?

Is the answer to change the default shell (e.g. to bash) and perhaps the homedir of local user nagios so I can generate the key, or is there another way?

  • Question: Is it bad practice to allow the nagios user to login?
  • Question: Is it bad practice to change the homedir, e.g. to /home/nagios?
  • Question: What is the recommended way of doing this?
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You can login as another user (even if that user doesn't have a shell) using su -ls /bin/bash username if you have the password (or are root). – Ulrich Schwarz Oct 27 '11 at 17:09
@UlrichSchwarz: Thanks, good tip! – Pimin Konstantin Kefaloukos Oct 27 '11 at 19:08
up vote 0 down vote accepted

Run su -c 'ssh-keygen -N ""' nagios to generate the key pair, or alternatively generate the key pair as another user then copy it in place into ~nagios/.ssh. Then run su -c 'ssh-copy-id someuser@remote-host' nagios to install the public key on the remote machine.

You can change the nagios user's home directory if you like, but I don't see the point.

There's no need to change the nagios user's shell for what you require here.

share|improve this answer
Would +1, but don't have the rep required yet. Thanks. – Pimin Konstantin Kefaloukos Oct 28 '11 at 7:42

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