gitlab-ci autoscaling config

gistfile1.txt

concurrent = 12
check_interval = 0

[[runners]]
  name = "aws-gitlab-runner-spawner"
  limit = 6
  url = "https://git.substrakt.com/ci"
  token = "xxxxx"
  executor = "docker+machine"
  [runners.docker]
    tls_verify = false
    image = "ruby:2.3.1"
    privileged = true
    disable_cache = false
    volumes = ["/cache"]
    shm_size = 0
  [runners.machine]
    IdleCount = 0
    MachineDriver = "amazonec2"
    MachineName = "runner-%s"
    MachineOptions = ["amazonec2-access-key=XXXX", "amazonec2-secret-key=XXXX", "amazonec2-ssh-user=ubuntu", "amazonec2-region=eu-west-2", "amazonec2-instance-type=m4.xlarge", "amazonec2-ami=ami-996372fd", "amazonec2-vpc-id=vpc-xxxxx", "amazonec2-subnet-id=subnet-xxxxx", "amazonec2-zone=a", "amazonec2-root-size=32", "amazonec2-request-spot-instance=true", "amazonec2-spot-price=0.03"]
    IdleTime = 1800

Thank you for such a useful article on https://substrakthealth.com/news/gitlab-ci-cost-savings/ .

Do you know what the minimum IAM policy should be?