amazon-web-services - 我们可以在 AWS::CloudFormation::Init 中收集实例元数据吗

Question

在配置AWS cloudwatch代理的时候，可以在{instance_id}里面包含awslogs.conf

[/var/log/cfn-hup.log]
file = /var/log/cfn-hup.log
log_group_name = my-log-group
log_stream_name = {instance_id}/cfn-hup

有没有办法在AWS::CloudFormation::Init中做到这一点？

具体来说，我希望将我的实例 ID 添加到文件部分

Resources: 
  MyLaunchConfig:
    Type: AWS::AutoScaling::LaunchConfiguration
    Metadata: 
      AWS::CloudFormation::Init: 
        config:
          files: 
            /opt/someconfig.conf: 
              content: |
                INSTANCE_ID={instance_id}
              mode: "000644"
              owner: "root"
              group: "root"

我的解决方法是在命令之后通过运行将 附加INSTANCE_ID到我的配置文件中：cfn-init

echo "INSTANCE_ID=$(curl http://169.254.169.254/latest/meta-data/instance-id)" >> /opt/someconfig.conf

有一个更好的方法吗？

Answer 1

我采用了 Marcin 在评论中指出的方法

Resources:
  MyLaunchConfig:
    Type: AWS::AutoScaling::LaunchConfiguration
    Metadata:
      AWS::CloudFormation::Init:
        config:
          files:
            /opt/someconfig.conf:
              content: |
                INSTANCE_ID='INSTANCE_ID_PLACEHOLDER'
              mode: "000644"
              owner: "root"
    Properties:
      # removed for brevity
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash -xe

          cfn-init -v \
            --stack ${AWS::StackName} \
            --resource MyLaunchConfig \
            --region ${AWS::Region}

          INSTANCE_ID=$(curl http://169.254.169.254/latest/meta-data/instance-id)

          sed -i "s/INSTANCE_ID_PLACEHOLDER/$INSTANCE_ID/g" /opt/someconfig.conf