Retrieve existing resource data using AWS Cloudformation-CodePudding

I need to retrieve existing data/properties of a given resource by using an AWS Cloudformation template. Is it possible? If it is how can I do it?

Example 1:

Output: Security Group ID which allows traffic on port 22

Example 2:

Output: Instance ID which use default VPC

CodePudding user response：

AWS CloudFormation is used to deploy infrastructure from a template in a repeatable manner. It cannot provide information on any resources created by any methods outside of CloudFormation.

Your requirements seem more relevant to AWS Config:

AWS Config provides a detailed view of the configuration of AWS resources in your AWS account. This includes how the resources are related to one another and how they were configured in the past so that you can see how the configurations and relationships change over time.

An AWS resource is an entity you can work with in AWS, such as an Amazon Elastic Compute Cloud (EC2) instance, an Amazon Elastic Block Store (EBS) volume, a security group, or an Amazon Virtual Private Cloud (VPC).

Using your examples, AWS Config can list EC2 instances and any resources that are connected to the instances, such as Security Groups and VPCs. You can easily click-through these relationship and view the configurations. It is also possible to view how these configurations have changed over time, such as:

When EC2 instance changed state (eg stopped, running)
When rules changed on Security Groups

Alternatively, you can simply make API calls to AWS services to obtain the current configuration of resources, such as calling DescribeInstances to obtain a list of Amazon EC2 instances and their configurations.