How many cores do you have, punk?

aws_cluster_size.rb

EC2 = {
  'm1.small'    => {:ram =>  1.7, :ecus =>  1.0, :cores =>  1, :storage =>  160},
  'm1.large'    => {:ram =>  7.5, :ecus =>  4.0, :cores =>  2, :storage =>  850},
  'm1.xlarge'   => {:ram => 15.0, :ecus =>  8.0, :cores =>  4, :storage => 1690},
  't1.micro'    => {:ram =>  0.6, :ecus =>  2.0, :cores =>  1, :storage =>    0}, # 613/1024 Gb RAM and actually less than 2 CPUs, but bursting up to 2
  'm2.xlarge'   => {:ram => 17.1, :ecus =>  6.5, :cores =>  2, :storage =>  420},
  'm2.2xlarge'  => {:ram => 34.2, :ecus => 13.0, :cores =>  4, :storage =>  850},
  'm2.4xlarge'  => {:ram => 68.4, :ecus => 26.0, :cores =>  8, :storage => 1690},
  'c1.medium'   => {:ram =>  1.7, :ecus =>  5.0, :cores =>  2, :storage =>  350},
  'c1.xlarge'   => {:ram =>  7.0, :ecus => 20.0, :cores =>  8, :storage => 1690},
  'cc1.4xlarge' => {:ram => 23.0, :ecus => 33.5, :cores =>  8, :storage => 1690}, # 2 x Intel Xeon X5570 quad-core “Nehalem” architecture CPUs
  'cc2.8xlarge' => {:ram => 60.5, :ecus => 88.0, :cores => 16, :storage => 3370}, # 2 x eight-core Intel Xeon CPUs
  'cg1.4xlarge' => {:ram => 22.0, :ecus => 33.5, :cores =>  8, :storage => 1690} # 2 x Intel Xeon X5570, quad-core “Nehalem” architecture CPUs (+ 2 x NVIDIA Tesla “Fermi” M2050 GPUs)
}

instance_types = Hash.new(0)

blob = %x<ec2-describe-instances | grep running>
blob.split("\n").each do |line|
  instance_type = line.split(/\s+/)[8]
  instance_types[instance_type] += 1
end

data = instance_types.reduce(Hash.new(0)) do |acc, (type, count)| 
  EC2[type].each do |metric, value|
    acc[metric] += count * value
  end
  acc
end

p data