- 1 year ago
Parse user/metadata/runtime data from cloudformation into EC2
To parse user, metadata, and runtime data from a CloudFormation template into an EC2 instance, you can use AWS CloudFormation's intrinsic functions and resource metadata.
Define the desired metadata in your CloudFormation template:
yamlMetadata:
AWS::CloudFormation::Init:
configSets:
myConfigSet:
- userdata
- metadata
userdata:
commands:
01_myCommand:
command: echo "This is a user command"
metadata:
AWS::CloudFormation::Designer:
id: "abc123"
MyCustomMetadata: "Custom metadata value"
Launch an EC2 instance using the CloudFormation template.
Inside the EC2 instance, you can access the metadata using the instance metadata service:
- User data: The user data can be accessed from the following URL:
http://169.254.169.254/latest/user-data
- Metadata: The metadata can be accessed from the following URL:
http://169.254.169.254/latest/meta-data
You can use tools like
curl
orwget
to retrieve the metadata from within the instance.For example, to retrieve the user data:
bashcurl http://169.254.169.254/latest/user-data
To retrieve specific metadata values:
bashcurl http://169.254.169.254/latest/meta-data/<metadata-key>
Replace
<metadata-key>
with the desired metadata key. For example, to retrieve theMyCustomMetadata
value from the previous example:bashcurl http://169.254.169.254/latest/meta-data/MyCustomMetadata
You can parse and process this data within your EC2 instance as needed.
- User data: The user data can be accessed from the following URL:
Note that the specific implementation may vary based on your CloudFormation template and the programming language or scripting environment you are using within the EC2 instance.