EC2_INSTANCE_CLASSES = %w(
  c3.2xlarge
  c3.4xlarge
  c3.8xlarge
  c3.large
  c3.xlarge
  c4.2xlarge
  c4.4xlarge
  c4.8xlarge
  c4.large
  c4.xlarge
  d2.2xlarge
  d2.4xlarge
  d2.xlarge
  d3.8xlarge
  g2.2xlarge
  g2.8xlarge
  i2.2xlarge
  i2.4xlarge
  i2.8xlarge
  i2.xlarge
  m3.2xlarge
  m3.large
  m3.medium
  m3.xlarge
  m4.10xlarge
  m4.2xlarge
  m4.4xlarge
  m4.large
  m4.xlarge
  r3.2xlarge
  r3.4xlarge
  r3.8xlarge
  r3.large
  r3.xlarge
  t2.large
  t2.medium
  t2.micro
  t2.nano
  t2.small
).freeze