From: "Sandor Szücs" <sandor.szuecs@...>
Date: 2009-05-17T06:26:25+09:00
Subject: Re: Desperate help needed with SSH


On 13.05.2009, at 11:05, alan@isdial.net wrote:
> -- 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'
>  ]

These instructions looks strange for me. Are you sure that these run
on all hosts?

Try to use other instructions that should work like
["echo foo", "sh -c 'echo bar'"]

Maybe your instructions kill the shell environment by calling exec
or something similar.

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

This part should be ok, but you can improve your code and use a block
for File.open().

  File.open("output/#{host}.txt", 'w') do |fn|
   ..
  end # fn.close not needed, because the block end close the file  
already.

> 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.

Calling ssh.exec!() twice in a session is not a problem.

irb> Net::SSH.start(host, user, :password => passwd) do |ssh|
irb>   ['sh -c "echo foo"', 'echo bar'].each do |command|
irb>    puts ssh.exec!(command)
irb>   end
irb> end
foo
bar


hth. regards, Sandor Szücs
--