更改计数时的 Terraform 循环 [英] Terraform cycle when altering a count

问题描述

我有一些资源，其 count 由变量参数化.这用于创建 VM 资源以及 null_resource，例如在它们上运行部署脚本.当我将计数值从 2 减少到 1 并应用时，出现错误.

I have some resources whose count is parameterised by a variable. This is used to create VM resources as well as null_resources for e.g. running deployment scripts on them. When I reduce the value of the count from 2 to 1 and apply, I get an error.

Terraform 毫无怨言地执行 plan.但是当我apply时，它告诉我有一个循环:

Terraform executes plan with no complaints. But when I apply, it tells me there is a cycle:

错误:循环:null_resource.network_connection_configuration[7](销毁)、null_resource.network_connection_configuration[8](销毁)、null_resource.network_connection_configuration[3](销毁)、null_resource.network_connection_configuration[4](销毁)、null_resource.network_connection_configuration[0](销毁)，null_resource.network_connection_configuration[6](销毁)，null_resource.network_connection_configuration[1](销毁)，null_resource.network_connection_configuration[9](销毁)，null_resource.network_connection_configuration[2](销毁)，null_resource.network_connection_configuration[10](销毁)、hcloud_server.kafka[2](销毁)、local.all_machine_ips、null_resource.network_connection_configuration(准备状态)、null_resource.network_connection_configuration[5](销毁)

Error: Cycle: null_resource.network_connection_configuration[7] (destroy), null_resource.network_connection_configuration[8] (destroy), null_resource.network_connection_configuration[3] (destroy), null_resource.network_connection_configuration[4] (destroy), null_resource.network_connection_configuration[0] (destroy), null_resource.network_connection_configuration[6] (destroy), null_resource.network_connection_configuration[1] (destroy), null_resource.network_connection_configuration[9] (destroy), null_resource.network_connection_configuration[2] (destroy), null_resource.network_connection_configuration[10] (destroy), hcloud_server.kafka[2] (destroy), local.all_machine_ips, null_resource.network_connection_configuration (prepare state), null_resource.network_connection_configuration[5] (destroy)

这是文件的相关部分:

variable kafka_count {
  default = 3
}

resource "hcloud_server" "kafka" {
  count       = "${var.kafka_count}"
  name        = "kafka-${count.index}"
  image       = "ubuntu-18.04"
  server_type = "cx21"
}

locals {
  all_machine_ips = "${hcloud_server.kafka.*.ipv4_address)}"
}

resource "null_resource" "network_connection_configuration" {
  count = "${length(local.all_machine_ips)}"

  triggers = {
    ips = "${join(",", local.all_machine_ips)}"
  }

  depends_on = [
    "hcloud_server.kafka"
  ]

  connection {
    type        = "ssh"
    user        = "deploy"
    host        = "${element(local.all_machine_ips, count.index)}"
    port        = 22
  }

// ... some file provisioners
}

当我尝试使用可视化找到循环时:

When I try to find the cycle using the visualisation:

terraform graph -verbose -draw-cycles

没有可见的循环.

当我使用 TF_LOG=1 时，调试日志不显示任何错误

When I use TF_LOG=1 the debug log doesn't show any errors

所以问题是我可以增加计数但不能减少它.我不想手动破解文件，因为这意味着我将来无法缩小！我正在使用 Terraform v0.12.1.

So the issue is that I can increase the count but not decrease it. I don't want to manally hack the file as it means I won't be able to scale down in future! I'm using Terraform v0.12.1.

有什么策略可以调试这种情况吗?

Are there any strategies for debugging this situation?

推荐答案

我在 0.12.x 中遇到了类似的问题 - 我在 aws_instance 资源中调用了一个配置程序，它给出了同样的错误你在增加资源的数量时有.

I had a similar issue with 0.12.x - I was calling a provisioner within an aws_instance resource, which was giving the same error you had when increasing the count for the resource.

我通过使用 self 对象 (self.private_ip) 来引用资源而不是使用 count.index 或 element().

I got around it by using the self object (self.private_ip) to reference the resource rather than using count.index or element().

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