ssh "user@host cmd" from root

amcohen · 07-11-2011, 08:34 PM

I’ve used your method to ssh without a password for a non-root user, say “user”. This works as long as I’m logged in as “user”.
But if I run as root, the following still asks for “user”‘s password.
i.e.: the following works w/o a password:
su – user
ssh host date
But the following asks to the password of “user”:
su – root
ssh user@host date

kbp · 07-11-2011, 09:52 PM

I'd have to guess that you've set up ssh key based authentication for root@host not user@host ... as these are 2 different users on the remote system you'll need to set it up for both.

amcohen · 07-12-2011, 12:42 AM

I copied the .ssh/authorized_key2 file under the "user" account onto the remote host. That's why if I become "user" on local host, I can ssh to user@remotehost without a password. What I'm actuaaly trying to do is to write to tape on the remote host; the local host is Solaris 10 while the remote host is RHEL 5.6; e. g.:
cd /; /bin/tar Ecfb - 200 opt | ssh user@remotehost 'dd of=/dev/nst0 bs=200b'

chrism01 · 07-12-2011, 12:56 AM

ssh works on a pair of keys.
The user's (local) key is only visible from the user's acct, not the root acct.
I think you want (if starting from root)

Code:

su - user -c "ssh user@remotehost ..."

theoretically you can skip 'user' part of ssh cmd, as it'll default to current user, if that's what you want.
http://linux.die.net/man/1/su

amcohen · 07-12-2011, 11:04 AM

That worked, thank you very much:
e.g.: su - user -c "ssh remotehost uname -a"