使用 cloudformation (yaml) 在 Ubuntu 实例中启动 cfn-init

Question

我尝试使用以下命令启动 cfn-init：

Fn::Base64: !Sub | 
  #!/bin/bash
  sudo apt-get -y install python-setuptools
  mkdir aws-cfn-bootstrap-latest
  curl https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-latest.tar.gz | tar xz -C aws-cfn-bootstrap-latest --strip-components 1
  sudo easy_install aws-cfn-bootstrap-latest
  sudo /usr/local/bin/cfn-init --stack !Ref 'AWS::StackName' --resource xxx --region !Ref 'AWS::Region'

第一步有效。我可以访问该实例并且安装了 cfn-init。当我在我的 ec2 实例中执行 cfn-init --stack.. 命令时，当我对 stackname 和 region 的值进行硬编码时它工作正常。

如何让它在 yaml 脚本中工作？它似乎无法读取 StackName 和区域的值。

Answer 1

如果您使用 !Sub，您需要用 ${} 包装您的变量，而不是使用 !Ref

试试这个

Fn::Base64: !Sub | 
  #!/bin/bash
  sudo apt-get -y install python-setuptools
  mkdir aws-cfn-bootstrap-latest
  curl https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-latest.tar.gz | tar xz -C aws-cfn-bootstrap-latest --strip-components 1
  sudo easy_install aws-cfn-bootstrap-latest
  sudo /usr/local/bin/cfn-init --stack ${AWS::StackName} --resource xxx --region ${AWS::Region}

If you specify template parameter names or resource logical IDs, such as ${InstanceTypeParameter}, AWS CloudFormation returns the same values as if you used the Ref intrinsic function. If you specify resource attributes, such as ${MyInstance.PublicIp}, AWS CloudFormation returns the same values as if you used the Fn::GetAtt intrinsic function.

有关详细信息，请查看 AWS - Fn::Sub

Answer 2

Fn::Base64: !Sub | 
  #!/bin/bash
  sudo apt-get -y install python-setuptools
  mkdir aws-cfn-bootstrap-latest
  curl https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-latest.tar.gz | tar xz -C aws-cfn-bootstrap-latest --strip-components 1
  sudo easy_install aws-cfn-bootstrap-latest
  sudo /usr/local/bin/cfn-init --stack ${AWS::StackName} --resource xxx --region ${AWS::Region}

如果 easy_install 不适用于 ubuntu 18.04，则使用以下命令：

python /usr/lib/python2.7/dist-packages/easy_install.py aws-cfn-bootstrap-latest

Answer 3

如果找不到 easy_install 命令，那么试试这个对我有用

"UserData": {
  "Fn::Base64": { "Fn::Join":["", [
    "#!/bin/bash\n",
    "apt-get update\n",
    "apt-get install -y python-setuptools\n",
    "mkdir -p /opt/aws/bin\n",
    "apt-get install -y wget\n",
    "wget https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-py3-latest.tar.gz\n",
    "python3 -m easy_install --script-dir /opt/aws/bin aws-cfn-bootstrap-py3-latest.tar.gz\n",
    "/usr/local/bin/cfn-init --stack ", { "Ref":"AWS::StackName" }, " --resource WebServer", " --region ", { "Ref": "AWS::Region" }, "\n",
    "\n",
    "/usr/local/bin/cfn-signal --exit-code $? '", { "Ref" : "WaitHandle" }, "'\n"
  ]]}
}

使用 cloudformation (yaml) 在 Ubuntu 实例中启动 cfn-init

Start cfn-init in Ubuntu instance with cloudformation (yaml)

yaml

amazon-web-services

amazon-cloudformation