• https://github.com/palantir/bouncer
• https://medium.com/palantir/bouncer-simple-aws-auto-scaling-rollovers-c5af601d65d4

resource "null_resource" "server_canary_bouncer" {
  triggers {
    trigger = "${join(",", aws_autoscaling_group.server.*.launch_configuration)}"
  }

  provisioner "local-exec" {
    command = "./bouncerw serial -a '${join(",", aws_autoscaling_group.server.*.name)}'"
  }
}