Terraform:如何从以前的 EC2 实例附加卷？

Question

我有一个 terraform 文件，它创建了一个 EC2 实例和几个卷:

resource "aws_instance" "generic" {
  count                  = "${lookup(var.INSTANCE_COUNT, var.SERVICE)}"
  ami                    = "${var.AMI}"
  instance_type          = "${lookup(var.INSTANCE_TYPE, var.BLD_ENV)}"
  subnet_id              = "${element(var.SUBNET,count.index)}"
  vpc_security_group_ids = ["${var.SECURITY_GROUP}"]
  key_name               = "${var.AWS_KEY_NAME}"
  availability_zone      = "${element(var.AWS_AVAILABILITY_ZONE,count.index)}"
  iam_instance_profile   = "${var.IAM_ROLE}"

  root_block_device {
    volume_type           = "gp2"
    delete_on_termination = "${var.DELETE_ROOT_ON_TERMINATION}"
  }

  ebs_block_device {
    device_name           = "${lookup(var.DEVICE_NAME,"datalake")}"
    volume_type           = "${lookup(var.DATALAKE_VOLUME_TYPE, var.SERVICE)}"
    volume_size           = "${var.NONDATADIR_VOLUME_SIZE}"
    delete_on_termination = "${var.DELETE_ROOT_ON_TERMINATION}"
    encrypted             = true
  }

  ebs_block_device {
    device_name           = "${lookup(var.DEVICE_NAME,"datalake_logdir")}"
    delete_on_termination = "${var.DELETE_ROOT_ON_TERMINATION}"
    volume_type           = "${lookup(var.LOGDIR_VOLUME_TYPE, var.SERVICE)}"
    volume_size           = "${var.NONDATADIR_VOLUME_SIZE}"
    encrypted             = true
  }

  volume_tags {
    Name = "${lookup(var.TAGS, "Name")}-${count.index}"
  }
}

如果 ec2 实例终止，我如何将现有卷附加到重新运行 terraform 时创建的新 ec2 实例？我希望 terraform 能够以某种方式从状态文件中得知实例已经消失但卷没有，因此它们应该附加到新创建的 EC2。

提前致谢!

Answer 1

首先，将您的实例、卷和卷附件分开，如下所示:

resource "aws_instance" "generic" {
  ami           = "${var.ami_id}"
  instance_type = "${var.instance_type}"
  count         = "${var.node_count}"
  subnet_id     = "${var.subnet_id}"
  key_name      = "${var.key_pair}"

  root_block_device = {
    volume_type           = "gp2"
    volume_size           = 20
    delete_on_termination = false
  }

  vpc_security_group_ids = ["${var.security_group_ids}"]
}

resource "aws_ebs_volume" "vol_generic_data" {
  size              = 120
  count             = "${var.node_count}"
  type              = "gp2"
}

resource "aws_volume_attachment" "generic_data_vol_att" {
  device_name = "/dev/xvdf"
  volume_id   = "${element(aws_ebs_volume.vol_generic_data.*.id, count.index)}"
  instance_id = "${element(aws_instance.vol_generic_data.*.id, count.index)}"
  count       = "${var.node_count}"
}

然后，如果您的实例被手动终止，TF 应检测到该实例已消失但仍以 TF 状态引用，并应尝试重新创建它并附加现有卷。我没有试过这个。但是，我已尝试将现有实例及其卷导入 TF 状态，因此相同的逻辑应该适用于仅导入卷并附加到现有 TF 托管实例。您应该能够像这样简单地导入现有卷:

terraform import module.generic.aws_ebs_volume.vol_generic_data vol-0123456789abcdef0

然后 TF 将附加卷或更新状态(如果已附加)。