您可能希望在cloudformation模板中定义cfn-hup，以便它放置包含所需变量的文件：

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...
  LaunchConfig:
    Type: "AWS::AutoScaling::LaunchConfiguration"
    Metadata:
      QBVersion: !Ref paramQBVersion
      AWS::CloudFormation::Init:
...
            /etc/cfn/hooks.d/cfn-auto-reloader.conf:
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.LaunchConfig.Metadata.AWS::CloudFormation::Init
                action=/opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource LaunchConfig --configsets wordpress_install --region ${AWS::Region}
                runas=root
              mode: "000400"
              owner: "root"
              group: "root"
...

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-hup.html

由于用户数据脚本中包含的初始cfn-init命令包含${AWS：：StackName} Psuedo参数，因此我们可以解析此脚本以提取它。下面的PowerShell脚本说明了该技术，类似的bash脚本可以在Linux示例上使用：

function Get-CfnInitStackName {
    [string]$token = Invoke-RestMethod -Headers @{"X-aws-ec2-metadata-token-ttl-seconds" = "21600"} -Method PUT -Uri http://169.254.169.254/latest/api/token
    $userDataScript = (Invoke-RestMethod -Headers @{"X-aws-ec2-metadata-token" = $token} -Method GET -Uri http://169.254.169.254/latest/user-data).script
    # Exact regex would be determined by your command usage in the UserData element of your Cloudformation template
    if ($userDataScript -match 'cfn-init.+ --stack (?<stackName>\S+) --resource') {
        $stackName = $Matches.stackName
    } else {
        throw "Stack name not found within user data script" + [System.Environment]::NewLine + $userDataScript
    }

    $stackName
}

function Invoke-CfnInitConfigset([string]$ConfigSet = 'deploy_full') {
    $stackName = Get-CfnInitStackName
    cfn-init --verbose --stack $stackName --resource Instance --region ap-southeast-2 --configsets $ConfigSet
    # TODO: Handle result code and disploy cfn-init.log output
}

注意，我考虑使用aws cloudformation describe-stack-resources调用提供来自元数据的ec2 instance-id作为--physical-resource-id参数。这确实有效，但这是对外部服务调用的额外依赖，并且需要扩展IAM示例配置文件权限。