terraform - terraform v0.12.0 のリソースにカンマ区切りの配列を渡すにはどうすればよいですか?

Question

次のコード ブロックでは、サーバー名の配列を attributes_json ブロックに渡そうとしています。

resource "aws_instance" "consul-server" {
    ami = var.consul-server
    instance_type = "t2.nano"
    key_name = var.aws_key_name
    iam_instance_profile = "dna_inst_mgmt"
    vpc_security_group_ids = [
        "${aws_security_group.yutani_consul.id}",
        "${aws_security_group.yutani_ssh.id}"
    ]
        subnet_id = "${aws_subnet.public_1_subnet_us_east_1c.id}"
        associate_public_ip_address = true
      tags = {
        Name = "consul-server${count.index}"
    }

    root_block_device {
        volume_size = "30"
        delete_on_termination = "true"
    }

    connection {
        type = "ssh"
        user = "chef"
        private_key = "${file("${var.aws_key_path}")}"
        timeout = "2m"
        agent = false
        host = self.public_ip
    }

   count = var.consul-server_count

   provisioner "chef" {
         attributes_json = <<-EOF
                {
                    "consul": {
                            "servers": ["${split(",",aws_instance.consul-server[count.index].id)}"]
                      }
                }
                EOF
        use_policyfile = true
        policy_name = "consul_server"
        policy_group = "aws_stage_enc"
        node_name       = "consul-server${count.index}"
        server_url      = var.chef_server_url
        recreate_client = true
        skip_install = true
        user_name       = var.chef_username
        user_key        = "${file("${var.chef_user_key}")}"
       version         = "14"
    }
   }

これを実行するとエラーが発生します：

Error: Cycle: aws_instance.consul-server[1], aws_instance.consul-server[0]

(これは、var.consul-server_count の変数でカウント 2 を宣言した後です)

これを行う適切な方法を誰かに教えてもらえますか?