Export AWS configuration as CloudFormation template

Question

I´m using AWS CLI and CloudFormation, and I could not find any reference in the documentation.

Does anybody know if it´s possible to create a CloudFormation template from a current configuration.

Let´s say that I want to get a CloudFormation template from my current security group configuration.

Any idea if it´s possible to export that configuration as a template using CLI?

Solution 1

Based on our experience we found 3 possible ways to translate existing manually deployed (from Web Console UI) AWS infra to Cloudformation (CF).

1. Using a new CloudFormation native introduced feature (since Nov 2019) that allows you to Import existing resources into a CloudFormation stack

2. Using aws cli execute $aws service_name_here describe for each element that make up your stack eg for RDS Database Stack:

• RDS Instance -> Type: AWS::RDS::DBInstance,
• RDS (EC2) SG -> Type: AWS::EC2::SecurityGroup,
• RDS Subnet Group -> Type: AWS::RDS::DBSubnetGroup and
• RDS DB Param Group -> Type: AWS::RDS::DBParameterGroup

And manually translate to CF based on the outputs obtained from the aws cli for each of the components. This approach usually requires more experience in both AWS and CF but the templates that you are creating can be structured and designed under good practices, fully parameterized (Sub, Ref, Join, Fn::GetAtt:, Fn::ImportValue), modular, applying conditions and in a 1st iteration the result would probably be close to the final state of the templates (interesting reference examples: https://github.com/widdix/aws-cf-templates/).

3. Using AWS CloudFormer:

• https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-using-cloudformer.html
• http://www.tothenew.com/blog/using-aws-cloudformer-to-create-template-of-existing-infrastructure
• NOTE: The resulting templates are not as "neat" as those developed manually under the approach (1), they will have all the IDs and values hard-coded and perhaps the structure of it will not follow the convention that you use for your CF templates, but of course it will provide a good starting point.

Extra points! :)

4. Using Terraforming (https://github.com/dtan4/terraforming). Considering the new version of Terraform 0.12.0-beta2 (already supported in stable release by terraform-provider-aws 2.7.0), with new features and its more friendly syntax, and without ignoring that it is an open source tool and cloud-provider agnostic, I would no dismiss the possibility of generating Terraform code based on existing AWS infra, if possible under the form of modules and sub-modules having as reference -> https://registry.terraform.io/ as an alternative to AWS CF.

5. Some other new alternatives to export your current deployed AWS infra to Cloudformation / Terraform code:

• https://former2.com
• https://modules.tf

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Related Article: https://medium.com/@exequiel.barrirero/aws-export-configuration-as-code-cloudformation-terraform-b1bca8949bca

Solution 2

It's not possible using the AWS CLI but you can use the CloudFormer [1] tool to create a CloudFormation template from existing resources. I've had decent success with it. The templates aren't as "pretty" as hand-made templates but they provide a good starting point.

[1] http://aws.amazon.com/developertools/6460180344805680

Solution 3

In addition to CloudFormer, you might want to take a look at Bellerophon: https://github.com/arminhammer/bellerophon.

Solution 4

I had some problems getting the tradidtional tools - mentioned above - working in our environment; we have a complicated API Gateway. Former2 didnt' find it at all (although seemed ideal for other resources)

I found another tool, "Terraformer" which extracts AWS into Terraform, which can then be turned into CloudFormation -or used directly as IaC.

https://github.com/GoogleCloudPlatform/terraformer#installation

Maybe that will work for others if the above tools don't.

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