Archive for February, 2011
Using Ruby to run commands on a lab of Linux machines
by Drew Dahl on Feb.24, 2011, under Linux, Programming
Lately, I’ve been getting acquainted with Rails development at work. It’s been a pretty steep learning curve (for that matter, I guess it still is), but I’ve enjoyed it thus far. So, with my new found Ruby skills (or, I guess more-so my new found need to learn Ruby), I wrote a script that uses SSH to iteratively connect to every computer in a lab and update them. This could be used for just about anything, but for my instance it was updating a lab. There was a bit more to my script as I needed to recompile some device drivers when there was a new kernel, but for simplicities sake, I’ve ripped them out. Hope this helps someone else!
First, you’ll need to install the ruby-ssh library.
sudo gem install highline
And, the script is:
require 'rubygems'
require 'net/ssh'
require 'highline/import'
hosts=[ "host1",
"host2" ]
cmds = ["yum -y update",
"init 6"]
username = "root"
# Assuming that all hosts have the same password
password = ask("Enter Password: ") { |q| q.echo = false }
hosts.each do |host|
Net::SSH.start( host , username, :password => password) do |ssh|
puts "Connected to #{host}"
cmds.each do |cmd|
puts "Performing #{cmd} on #{host}"
output = ssh.exec! cmd do |ch, stream, data|
if stream == :stderr
puts "Error: #{data}"
else
puts data
end
end
end
end
end
And, that’s all there is to it! There’s a real lack of comments, but I feel it’s pretty self-explanatory. Enjoy!
