在terraform中循环变量

Question

我对terraform真的很陌生,想要做这个工作.我能够创建vpc,公共子网并获取它们的ID,现在我想在每个子网内创建一个ec2实例,当我尝试运行ec2模块时,它只在第一个子网内创建实例并忽略其他子网.这是我的代码片段.

输出子网ID:

output "public_subnets_id" {
  value = "${join(",", aws_subnet.public.*.id)}"
}

这里的示例输出:

public_subnets_id = subnet-84aae6f4,subnet-a12124e8

这是我的代码,我试图将其拆分并在每个子网内创建实例,但只能创建到第一个子网.

subnet_id = "${element(split(",", var.subnet_id), count.index)}"

Answer 1

我在不同的可用区域中展开了EC2实例,如下所示:

variable "zones" {
  default = {
    zone0 = "us-east-1a"
    zone1 = "us-east-1b"
    zone2 = "us-east-1c"
  }
}

variable "cidr_blocks" {
  default = {
    zone0 = "172.32.0.0/20"
    zone1 = "172.32.16.0/20"
    zone2 = "172.32.32.0/20"
  }
}

variable "dockerhost_instances" {
  default = "5"
}

resource "aws_subnet" "public-subnet" {
  ...
  cidr_block = "${lookup(var.cidr_blocks, format("zone%d", count.index))}"
  availability_zone = "${lookup(var.zones, format("zone%d", count.index))}"
  count = 3
}


resource "aws_instance" "host" {
  ...
  subnet_id = "${element(aws_subnet.public-subnet.*.id,count.index)}"
  count = "${var.dockerhost_instances}"
}

因为${element(...)}函数包装,结果是三个子网和五个主机分布在子网上:

us-east-1a : host.0 host.3
us-east-1b : host.1 host.4
us-east-1c : host.2

Answer 2

看来问题出在resource "aws_instance"定义上，

count ="${length(split(",", var.subnet_id))}"

https://github.com/arbabnazar/terraform-aws/blob/1891cf2a31a0e9db425dd5243018d46eeb6d5330/modules/ec2/main.tf#L5

如果直接将count设置为2，会得到两个实例吗？

我的理解是，ec2资源的计数应该设置为默认值，例如2，或者直接在variable.tf中定义一个数字，然后在资源ec2中ec2_num调用它var.ec2_num