Simple rsh issue

Stevie-B-242 · 02-17-2008, 08:25 PM

...once again, I'm obviously a newbie with a question like this but here's a chance to solve a simple issue and in the process show that you are smarter than me. %-)

I'm trying to configure and enable rsh on a node in a small Linux cluster (RHEL 5).

I've modified
/etc/xinetd.d/rsh
/etc/xinetd.d/rlogin
/etc/xinetd.d/rexec
to set "disable = no"

added lines for rsh and rlogin to /etc/securetty

and then issued a #services xinetd restart

but when I try to test rsh locally on the node, I get the following:

[root@C1-N1 ~]# rsh localhost
connect to address 127.0.0.1 port 543: Connection refused
Trying krb4 rlogin...
connect to address 127.0.0.1 port 543: Connection refused
trying normal rlogin (/usr/bin/rlogin)
Password:

I imagine I've made a really simple mistake somewhere along the way...do you know where I've gone wrong?

Thanks in advance for any help you can offer on this!

--Steve

Simon Bridge · 02-17-2008, 08:36 PM

Quote:

I'm trying to configure and enable rsh

... do not use rsh, use ssh.

http://www.fnal.gov/docs/strongauth/encryptconn.html

Stevie-B-242 · 02-17-2008, 08:45 PM

...thanks for the quick reply Simon.

I know that SSH is vastly preferred in most instances to rsh because SSH is secure and rsh is not.

However, as I mentioned in a different thread today, this is for a small lab cluster which is completely isolated from the outside world.

...In this instance, I'm not looking for the most secure implementation... I just desperately need something that I can get working right now.

Thanks.
--Steve

Simon Bridge · 02-17-2008, 08:54 PM

ssh is also easier/easier to set up.
(I think I replied to your other thread... lost track...)
http://suso.org/docs/shell/ssh.sdf

custangro · 02-18-2008, 06:00 PM

You need to have a .rhosts in the home directory of the user you are trying to rsh as....

~/.rhosts

You need to put the IP address (or if you have DNS set up the fqdn) in the file.

And Simon Bridge is right...don't use rsh...

-C

IanVaughan · 09-24-2009, 07:11 AM

Yes SSH might be better than RSH, but rsh can allow commands to be sent.
As I want to script some actions from a remote host that are to be performed on the target, rsh is better.

pwc101 · 09-24-2009, 07:16 AM

What's stopping you from sending those commands with SSH?

Code:

ssh user@remotehost "date > didthiswork"

I just tested this and it successfully created a file called didthiswork on the remote host.

IanVaughan · 09-24-2009, 09:27 AM

Yep, basic commands work, but what about shell type/env setup?
SSH with and without command gives different results? env is different?

works as expected

Code:

[a ~]$ ssh 172.24.40.100
Last login: Mon Jan  1 06:07:24 2001 from 172.24.41.78
[b ~]# /path/script.sh

gives me error consistent with env setup

Code:

[a ~]$ ssh 172.24.40.100 /path/script.sh

Which implies the latter is running the script.sh on host a, when I want to
'launch' in from a, and 'run' it on b!?

IanVaughan · 09-24-2009, 09:32 AM

Redirecting my previous question to here as more on subject.

pwc101 · 09-24-2009, 09:47 AM

How about sourcing the profile before running the command?

Code:

ssh user@host "source /etc/profile; /path/script.sh"

You might find it best to change that to ~/.bash_profile, ~/.bashrc, or whatever.

IanVaughan · 09-24-2009, 10:08 AM

Quote:

Originally Posted by pwc101

How about sourcing the profile before running the command?

Code:

ssh user@host "source /etc/profile; /path/script.sh"

You might find it best to change that to ~/.bash_profile, ~/.bashrc, or whatever.

Code:

ssh 172.24.40.100 "source /root/.bash_profile; /path/script.sh"

Worked! You ppl are great! Cheers.

felton57 · 09-24-2010, 09:19 AM

My problem is the same as above. Here is my dilemma:

I want to shutdown a number of computers in my lab. Hostnames are jmud1, jmud2, jmud3 and jmud4 .... jmud20.

Current script or command used:

#!/bin/csh

foreach num (`/root/tools/machines`)
rsh jmud{num} /sbin/shutdown -hy 0 &

end

#End of Script

How do I replace is with ssh or something useable in RHEL5?

pwc101 · 09-24-2010, 10:15 AM

Without knowing what /root/tools/machines does or contains, I'll assume it has the hostnames on separate lines in it. If so, then you could try:

Code:

#!/bin/bash

# Iterate through each remote host in the file /root/tools/machines 
while read rhost; do
    ssh root@$rhost "/sbin/shutdown -h now"
done < /root/tools/machines

You'll have to ssh in as root (often considered a bad idea), or set up sudo to allow a different, less privileged user to execute /sbin/shutdown.

Edit: You can also specify users who are allowed to shutdown the machine in /etc/shutdown.allow without the need to set up sudo. You do need to pass -a to the shutdown command, though. See man shutdown for more info.