How can I pass a parameters of type List<AWS::EC2::Subnet::Id> as a comma separated string?
I have the following template:
{
"AWSTemplateFormatVersion": "2010-09-09",
"Parameters": {
"PrivateSubnets": {
"Description": "The private subnets in which Beanstalk EC2 instances will created",
"Type": "List<AWS::EC2::Subnet::Id>"
},
"PublicSubnets": {
"Description": "The public subnets in which the Beanstalk ELBs will be created",
"Type": "List<AWS::EC2::Subnet::Id>"
}
},
"Resources": {
"MyApp": {
"Type": "AWS::ElasticBeanstalk::Application",
"Properties": {
"ApplicationName": "MyApp",
"Description": "AWS Elastic Beanstalk Application"
}
},
"ConfigTemplate": {
"Type": "AWS::ElasticBeanstalk::ConfigurationTemplate",
"Properties": {
"ApplicationName": { "Ref": "MyApp" },
"Description": "Microsite Beanstalk config template",
"OptionSettings": [
{ "Namespace": "aws:ec2:vpc", "OptionName": "ELBSubnets", "Value": { "Ref": "PublicSubnets" } },
{ "Namespace": "aws:ec2:vpc", "OptionName": "Subnets", "Value": { "Ref": "PrivateSubnets"} }
],
"SolutionStackName": "64bit Amazon Linux 2016.03 v2.1.7 running PHP 5.6"
}
}
}
}
When I attempt to create the stack, I get the following error:
CREATE_FAILED AWS::ElasticBeanstalk::ConfigurationTemplate ConfigTemplate Value of property Value must be of type String
An attempt to use Fn:Join to write the content of the private and public subnets as comma separated strings, e.g.
{ "Namespace": "aws:ec2:vpc", "OptionName": "ELBSubnets", "Value": { "Fn:Join": [",", { "Ref": "PublicSubnets" }]} },
{ "Namespace": "aws:ec2:vpc", "OptionName": "Subnets", "Value": { "Fn:Join": [",", { "Ref": "PrivateSubnets"}]} },
result in
Template validation error: Template Error: Encountered unsupported function: Fn:Join Supported functions are: [Fn::Base64, Fn::GetAtt, Fn::GetAZs, Fn::ImportValue, Fn::Join, Fn::FindInMap, Fn::Select, Ref, Fn::Equals, Fn::If, Fn::Not, Condition, Fn::And, Fn::Or, Fn::Contains, Fn::EachMemberEquals, Fn::EachMemberIn, Fn::ValueOf, Fn::ValueOfAll, Fn::RefAll, Fn::Sub]
