如何在Packer AMI数据源中配置地域以解决MissingRegion错误

在CI/CD流水线中使用Packer调用最新AWS AMI时触发错误：

Error: Datasource.Execute failed: Error querying AMI: MissingRegion: could not find region configuration

已在Packer的amazon-ami数据源块中指定region参数，但未生效；尝试在Packer构建命令中传递地域变量、在GitHub Workflow中设置环境变量后问题仍存在。相关配置如下：

Packer配置 #

packer {
   required_plugins {
     amazon = {
       version = ">= 0.0.1"
       source  = "github.com/hashicorp/amazon"
     }
   }
}

data "amazon-ami" "my_ami_ds" {
  filters = {
    virtualization-type = "hvm"
    name                = "my-test-ami*"
    root-device-type    = "ebs"
  }
  owners      = ["${var.aws_account_id}"]
  most_recent = true
  region      = "${var.aws_region}"
}

GitHub Workflow代码 #

name: packer

on:
  workflow_run:
    workflows: [msbuild]
    types:
      - completed

jobs:
  packer:
    runs-on: my-runner
    strategy:
      matrix:
        environment: ['dev','test','prod']

    steps:
      - name: Ensure previous build succeeded
        if: ${{ github.event.workflow_run.conclusion != 'success' }}
        run: exit 1

      - uses: actions/checkout@v2.4.2

      - name: Setup AWS configuration
        run: scripts/actions-setup-aws-config

      - name: Setup Packer
        uses: hashicorp-contrib/setup-packer@v1
        with:
          packer-version: 1.8.2

      - name: Get release info
        id: release_info
        uses: actions/github-script@v6
        with:
          script: |
            const allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
               owner: context.repo.owner,
               repo: context.repo.repo,
               run_id: context.payload.workflow_run.id,
            });
            return {
              artifactId: artifact.id,
              version: artifact.name.replace(artifactBaseName, "")
            };
      - name: Set release info
        id: release_output
        run: |
          ARTIFACT_ID=$(echo '${{ steps.release_info.outputs.result }}' | jq '.artifactId')
          ARTIFACT_URL=https://api.github.com/repos/${{ github.repository }}/actions/artifacts/$ARTIFACT_ID/zip
          VERSION=$(echo '${{ steps.release_info.outputs.result }}' | jq '.version')
          echo "::set-output name=artifact_url::$ARTIFACT_URL"
          echo "::set-output name=version::$VERSION"
      - name: Packer init
        working-directory: ./work_dir
        run: packer init .

      - name: Packer build
        working-directory: ./work_dir
        run: |
          packer build -timestamp-ui \
            --var-file "variables/${{ matrix.environment }}.pkrvars.hcl" \
            --var build_version=${{ steps.release_output.outputs.version }} \
            --var artifacts_url=${{ steps.release_output.outputs.artifact_url }} \
            --var artifacts_token=${{ secrets.GITHUB_TOKEN }} .
      - name: Get AMI ID
        working-directory: ./work_dir
        run: |
          AMI_ID=$(jq -r '.builds[-1].artifact_id' manifest.json | cut -d ":" -f2)
          echo "Created AMI with ID $AMI_ID" >> $GITHUB_STEP_SUMMARY

AWS配置脚本 #

#!/bin/bash

set -o errexit
set -o pipefail
set -o nounset

source "$(dirname "${0}")/common"

#ensure_invoked_from_repo
#ensure_invoked_in_github_actions

repo_root_path="$(git rev-parse --show-toplevel)"
aws_config_path="${repo_root_path}/.aws_config"

rm -f "${aws_config_path}"
touch "${aws_config_path}"

source "$(dirname "${0}")/aws-account-ids"

for env in "${!aws_account_ids[@]}"; do
   cat <<EOF >>"${aws_config_path}"
   [profile company-${env}]
   region            = eu-west-1
   role_arn          = arn:aws:iam::${aws_account_ids[${env}]}:role/ciadmin
  credential_source = Ec2InstanceMetadata
  EOF
  done

echo "AWS_CONFIG_FILE=${aws_config_path}" >> "${GITHUB_ENV}"

已尝试的解决方法 #

• 修改Packer构建命令，直接传递AWS_DEFAULT_REGION变量

  - name: Packer build
    working-directory: ./work_dir
    run: |
      packer build -timestamp-ui \
        --var AWS_DEFAULT_REGION=eu-west-1
  

• 在Workflow顶层添加AWS_REGION环境变量

  name: packer
  env:
      AWS_REGION: eu-west-1
  on:
    workflow_run:
    workflows: [msbuild]
    types:
        - completed
  

1. 确认aws_region变量是否正确传入 #

检查variables/${{ matrix.environment }}.pkrvars.hcl文件中是否定义了aws_region变量，且值为eu-west-1（或对应环境的地域）。如果该变量未定义，Packer数据源中的region = "${var.aws_region}"会为空，直接导致地域缺失。

2. 明确指定AWS_PROFILE环境变量 #

你的AWS配置脚本生成了带环境后缀的profile（如company-dev），但Workflow中未指定使用哪个profile。在Packer构建步骤前添加环境变量：

- name: Set AWS Profile
  run: echo "AWS_PROFILE=company-${{ matrix.environment }}" >> $GITHUB_ENV

这样Packer会自动读取对应profile中的地域配置，无需额外传递参数。

3. 直接在Packer构建命令中强制传递aws_region变量 #

确保aws_region变量被明确传入，修改构建命令：

- name: Packer build
  working-directory: ./work_dir
  run: |
    packer build -timestamp-ui \
      --var-file "variables/${{ matrix.environment }}.pkrvars.hcl" \
      --var aws_region=eu-west-1 \
      --var build_version=${{ steps.release_output.outputs.version }} \
      --var artifacts_url=${{ steps.release_output.outputs.artifact_url }} \
      --var artifacts_token=${{ secrets.GITHUB_TOKEN }} .

4. 验证AWS配置文件是否生效 #

在Setup AWS配置步骤后添加验证命令，确认配置文件生成正确：

- name: Verify AWS Config
  run: cat $AWS_CONFIG_FILE

检查输出中是否包含对应环境的profile，且region字段正确设置为eu-west-1。

5. 升级Packer版本 #

你使用的Packer 1.8.2版本较旧，可能存在数据源地域解析的bug。尝试升级到最新稳定版：

- name: Setup Packer
  uses: hashicorp-contrib/setup-packer@v1
  with:
    packer-version: "latest"

内容的提问来源于stack exchange，提问作者srk786