From: alan@...
Date: 2009-05-13T18:05:55+09:00
Subject: Desperate help needed with SSH

Hi you Ruby Guru's

I have a small problem thats driving me crazy. I am trying to connect to 
multiple ssh servers (1 at a time), run a number of commands and capture 
the output to a unique file for each server.

My code looks like this :

-- snip --

require 'rubygems'
require 'net/ssh'
  
hosts = ['10.0.255.1' , '10.0.255.2' , '10.0.255.3']

instructions = [
  'sh version',
  'sh cdp ne'
  ]

hosts.each do |host|
  Net::SSH.start(host, 'user', :password => 'password') do |ssh|
  
    fn = File.open("output\/#{host}.txt", 'w')
    instructions.each do |command|
      fn.puts "|--------\[#{command}\]--------------------------"
      fn.puts ssh.exec!(command)      
    end
    fn.close
  end
end    

-- snip --

When I run this I get the following error :

Net::SSH::ChannelOpenFailed: (4)

If I remove the instructions.each loop and run only a single command. Life 
is good and it all works. If I add a second ssh.exec! or the loop, the 
error returns.

It appears that the ssh.exec! closes the connection. How do I keep it open 
to allow me to run a second command?

Alan.