Cloudformation template properties documentation discrepancy - amazon-web-services

Question

I'm creating my first Cloudformation template using an archived Github project from an AWS Blog:
https://aws.amazon.com/blogs/devops/part-1-develop-deploy-and-manage-for-scale-with-elastic-beanstalk-and-cloudformation-series/
https://github.com/amazon-archives/amediamanager
The template amm-elasticbeanstalk.cfn.json declares an Elastic Beanstalk resource, outlined here:
"Resources": {
"Application": {
"Type": "AWS::ElasticBeanstalk::Application",
"Properties": {
"ConfigurationTemplates": [{...}],
"ApplicationVersions": [{...}]
}
}
}
From the documentation I'm under the impression that AWS::ElasticBeanstalk::ApplicationVersion and AWS::ElasticBeanstalk::ConfigurationTemplate must be defined as separate resources, yet the example I'm working from is using the same AWSTemplateFormatVersion as the documentation. Is this a "shorthand" where namespaces can be nested if they have the same parent (i.e. AWS::ElasticBeanstalk)? Is it documented somewhere?
In the same file AWS::ElasticBeanstalk::Environment is defined as a separate resource - is this just a stylistic choice, perhaps because the environment configuration is so long?

Answer 1

Elastic Beanstalk consists of Applications and Environments components. Basically each environment runs only one application version at a time, however, you can run the same application version in many environments at the same time. Application versions and Saved configurations are part of the Application resource that's why it's possible to define it within the AWS::ElasticBeanstalk::Application resource properties. Environment however is a separate logical component of Elastic Beanstalk so it's impossible to declare it from within the Application resource.
For better readability I would suggest declaring all the resources separately as per this example. Also when using this approach you can directly reference the TemplateName and VersionLabel in the AWS::ElasticBeanstalk::Environment resource.
Alternatively if you want to stick to the github example you can adjust the above example to look like this:
{
"AWSTemplateFormatVersion": "2010-09-09",
"Resources": {
"sampleApplication": {
"Type": "AWS::ElasticBeanstalk::Application",
"Properties": {
"Description": "AWS Elastic Beanstalk Sample Application",
"ApplicationVersions": [{
"VersionLabel": "Initial Version",
"Description": "Initial Version",
"SourceBundle": {
"S3Bucket": {
"Fn::Sub": "elasticbeanstalk-samples-${AWS::Region}"
},
"S3Key": "php-newsample-app.zip"
}
}],
"ConfigurationTemplates": [{
"TemplateName": "DefaultConfiguration",
"Description": "AWS ElasticBeanstalk Sample Configuration Template",
"OptionSettings": [
{
"Namespace": "aws:autoscaling:asg",
"OptionName": "MinSize",
"Value": "2"
},
{
"Namespace": "aws:autoscaling:asg",
"OptionName": "MaxSize",
"Value": "6"
},
{
"Namespace": "aws:elasticbeanstalk:environment",
"OptionName": "EnvironmentType",
"Value": "LoadBalanced"
},
{
"Namespace": "aws:autoscaling:launchconfiguration",
"OptionName": "IamInstanceProfile",
"Value": {
"Ref": "MyInstanceProfile"
}
}
],
"SolutionStackName": "64bit Amazon Linux 2018.03 v2.9.11 running PHP 5.5"
}]
}
},
"sampleEnvironment": {
"Type": "AWS::ElasticBeanstalk::Environment",
"Properties": {
"ApplicationName": {
"Ref": "sampleApplication"
},
"Description": "AWS ElasticBeanstalk Sample Environment",
"TemplateName": "DefaultConfiguration",
"VersionLabel": "Initial Version"
}
},
"MyInstanceRole": {
"Type": "AWS::IAM::Role",
"Properties": {
"AssumeRolePolicyDocument": {
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": {
"Service": [
"ec2.amazonaws.com"
]
},
"Action": [
"sts:AssumeRole"
]
}
]
},
"Description": "Beanstalk EC2 role",
"ManagedPolicyArns": [
"arn:aws:iam::aws:policy/AWSElasticBeanstalkWebTier",
"arn:aws:iam::aws:policy/AWSElasticBeanstalkMulticontainerDocker",
"arn:aws:iam::aws:policy/AWSElasticBeanstalkWorkerTier"
]
}
},
"MyInstanceProfile": {
"Type": "AWS::IAM::InstanceProfile",
"Properties": {
"Roles": [
{
"Ref": "MyInstanceRole"
}
]
}
}
}
}

Answer 2

Just want to point out that AWS silently phased out the option of having the ApplicationVerions key under an AWS::ElasticBeanstalk::Application's Properties. It was still working in July 2022 but I noticed it stopped some time in August 2022, giving the error in the CloudFormation stack's Event tab:
Properties validation failed for resource TheEBAppResName with message: #: extraneous key [ApplicationVersions] is not permitted
where TheEBAppResName is the name of your AWS::ElasticBeanstalk::Application resource.
The only solution now is to follow the current AWS example and use a separate AWS::ElasticBeanstalk::ApplicationVersion resource.
Interestingly, I can't seem to find any documentation on the obsolete ApplicationVerions property anymore and the AWS blog that you linked to is no longer available, but I did find it cached on the Wayback machine. Even the earliest AWS doc on GitHub for AWS::ElasticBeanstalk::Application doesn't mention the ApplicationVerions property. Seems like AWS silently deprecated it sometime between when the blog was posted in April 2014 and that earliest GitHub doc page in December 2017, but didn't actually remove the option until last month, August 2022.