Reusable Configusets

Typically, configsets are directly hardcoded into the CloudFormation template. Unfortunately, this makes them hard to reuse. IE: You copy and paste the configset code between CloudFormation templates.

With Lono, configsets are define separately from the template. Lono takes the configsets and adds them into your CloudFormation templates. This allows them to be reusable with different templates.

Example

Let’s say you have two blueprints: ec2 and asg.

• The ec2 blueprint has an Instance resource.
• The asg blueprint has an LaunchConfiguration resource.

You can reuse the same configsets for both blueprints. Example:

configs/ec2/configsets/base.rb:

configset("cfn-hup", resource: "Instance")
configset("httpd", resource: "Instance")

configs/asg/configsets/base.rb:

configset("cfn-hup", resource: "LaunchConfiguration")
configset("httpd", resource: "LaunchConfiguration")

UserData cfn-init

The UserData script for the ec2 blueprint calls cfn-init like this:

#!/bin/bash
/opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource Instance --region ${AWS::Region}

The asg blueprint’s UserData calls cfn-init like this:

#!/bin/bash
/opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource LaunchConfiguration --region ${AWS::Region}

The beauty is that you can choose whichever configsets are needed. You don’t have to copy and paste the configset into different templates. Just configure them, and lono injects them into the CloudFormation template for you.

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