get-host-specs.rb

#!/usr/bin/env ruby 
require 'rubygems' 
require 'net/ssh'  
#need to install gem 'parallel'
require 'parallel'
#Path to file with hosts in it, one per line
HOSTFILE = "hosts.txt"
USER = 'root' 
#ssh key path
KEYS = [ "~/.ssh/key" ]
#command to run that outputs hostname, memory, disk and cores
COMMAND = <<-STR
  echo -e -n "$HOSTNAME\t" && free -m | awk 'NR==2{printf "%s\t",$2 }' && df -lP | awk '{total+=$2} END {printf "%d\t", total/(1024*1024) + 0.5}' && awk '$1=="processor"{ count++ } END { printf "%d", count }' /proc/cpuinfo
STR

def fetch_info_into_array(hostname, array)
	begin	
		Net::SSH.start(hostname, USER, :keys => KEYS ) do|ssh|
			array << ssh.exec!(COMMAND) + "\n"
		end
	rescue Exception => e
  	puts "#{hostname} EXCEPTION" + e.to_s
		array << "#{hostname}\tunknown\n"
	end
end

output = ["Hostname\tMemory MB\tDisk Size Total GB\tCPU Cores\n"]
File.open(HOSTFILE, "r") do |f|
 Parallel.each(f.each_line, :in_threads => 8) do |line|
    fetch_info_into_array(line.strip, output)
	end
end

#save result to file
File.open('output.txt', 'w') {|f| f.puts(output) }
puts output