…rately to avoid masking return values.

…shes

…o block_device_mappings single strings

…ot tasks fails

The complete setup on the AWS end can be configured
with the following Terraform configuration. It generates
a ./credentials.sh which I just copy/pasted in to the
create-amis.sh script near the top. Note: the entire stack
of users and bucket can be destroyed at the end of the
import.

    variable "region" {
      type = string
    }
    variable "availability_zone" {
      type = string
    }

    provider "aws" {
      region = var.region
    }

    resource "aws_s3_bucket" "nixos-amis" {
      bucket_prefix = "nixos-amis-"
      lifecycle_rule {
        enabled = true
        abort_incomplete_multipart_upload_days = 1
        expiration {
          days = 7
        }
      }
    }

    resource "local_file" "credential-file" {
      file_permission = "0700"
      filename = "${path.module}/credentials.sh"
      sensitive_content = <<SCRIPT
    export service_role_name="${aws_iam_role.vmimport.name}"
    export bucket="${aws_s3_bucket.nixos-amis.bucket}"
    export AWS_ACCESS_KEY_ID="${aws_iam_access_key.uploader.id}"
    export AWS_SECRET_ACCESS_KEY="${aws_iam_access_key.uploader.secret}"
    SCRIPT
    }

    # The following resources are for the *uploader*
    resource "aws_iam_user" "uploader" {
      name = "nixos-amis-uploader"
    }

    resource "aws_iam_access_key" "uploader" {
      user = aws_iam_user.uploader.name
    }

    resource "aws_iam_user_policy" "upload-to-nixos-amis" {
      user = aws_iam_user.uploader.name

      policy = data.aws_iam_policy_document.upload-policy-document.json
    }

    data "aws_iam_policy_document" "upload-policy-document" {
      statement {
        effect = "Allow"

        actions = [
          "s3:ListBucket",
          "s3:GetBucketLocation",
        ]

        resources = [
          aws_s3_bucket.nixos-amis.arn
        ]
      }

      statement {
        effect = "Allow"

        actions = [
          "s3:PutObject",
          "s3:GetObject",
          "s3:DeleteObject",
        ]

        resources = [
          "${aws_s3_bucket.nixos-amis.arn}/*"
        ]
      }

      statement {
        effect = "Allow"
        actions = [
          "ec2:ImportSnapshot",
          "ec2:DescribeImportSnapshotTasks",
          "ec2:DescribeImportSnapshotTasks",
          "ec2:RegisterImage",
          "ec2:DescribeImages"
        ]
        resources = [
          "*"
        ]
      }
    }

    # The following resources are for the *vmimport service user*
    # See: https://docs.aws.amazon.com/vm-import/latest/userguide/vmie_prereqs.html#vmimport-role
    resource "aws_iam_role" "vmimport" {
      assume_role_policy = data.aws_iam_policy_document.vmimport-trust.json
    }

    resource "aws_iam_role_policy" "vmimport-access" {
      role = aws_iam_role.vmimport.id
      policy = data.aws_iam_policy_document.vmimport-access.json
    }

    data "aws_iam_policy_document" "vmimport-access" {
      statement {
        effect = "Allow"
        actions = [
          "s3:GetBucketLocation",
          "s3:GetObject",
          "s3:ListBucket",
        ]
        resources = [
          aws_s3_bucket.nixos-amis.arn,
          "${aws_s3_bucket.nixos-amis.arn}/*"
        ]
      }
      statement {
        effect = "Allow"
        actions = [
          "ec2:ModifySnapshotAttribute",
          "ec2:CopySnapshot",
          "ec2:RegisterImage",
          "ec2:Describe*"
        ]
        resources = [
          "*"
        ]
      }
    }

    data "aws_iam_policy_document" "vmimport-trust" {
      statement {
        effect = "Allow"
        principals {
          type = "Service"
          identifiers = [ "vmie.amazonaws.com" ]
        }

        actions = [
          "sts:AssumeRole"
        ]

        condition {
          test = "StringEquals"
          variable = "sts:ExternalId"
          values = [ "vmimport" ]
        }
      }
    }

Co-authored-by: Cole Helbling <cole.e.helbling@outlook.com>