ase64 Encoded UserData Property
This example shows the assembly of a UserData property using the Fn::Base64 and Fn::Join functions. The references MyValue and MyName are parameters that must be defined in the Parameters section of the template. The literal string Hello World is just another value this example passes in as part of the UserData.
JSON
"UserData" : {
“Fn::Base64” : {
“Fn::Join” : [ “,”, [
{ “Ref” : “MyValue” },
{ “Ref” : “MyName” },
“Hello World” ] ]
}
}
YAML
UserData:
Fn::Base64: !Sub |
Ref: MyValue
Ref: MyName
Hello World
Base64 Encoded UserData Property with AccessKey and SecretKey
This example shows the assembly of a UserData property using the Fn::Base64 and Fn::Join functions. It includes the AccessKey and SecretKey information. The references AccessKey and SecretKey are parameters that must be defined in the Parameters section of the template.
JSON
"UserData" : {
“Fn::Base64” : {
“Fn::Join” : [ “”, [
“ACCESS_KEY=”, { “Ref” : “AccessKey” },
“SECRET_KEY=”, { “Ref” : “SecretKey” } ]
]
}
}
YAML
UserData:
Fn::Base64: !Sub |
ACCESS_KEY=${AccessKey}
SECRET_KEY=${SecretKey}
Parameters Section with One Literal String Parameter
The following example depicts a valid Parameters section declaration in which a single String type parameter is declared.
JSON
"Parameters" : {
“UserName” : {
“Type” : “String”,
“Default” : “nonadmin”,
“Description” : “Assume a vanilla user if no command-line spec provided”
}
}
YAML
Parameters:
UserName:
Type: String
Default: nonadmin
Description: Assume a vanilla user if no command-line spec provided
Parameters Section with String Parameter with Regular Expression Constraint
The following example depicts a valid Parameters section declaration in which a single String type parameter is declared. The AdminUserAccount parameter has a default of admin. The parameter value must have a minimum length of 1, a maximum length of 16, and contains alphabetic characters and numbers but must begin with an alphabetic character.
JSON
"Parameters" : {
“AdminUserAccount”: {
“Default”: “admin”,
“NoEcho”: “true”,
“Description” : “The admin account user name”,
“Type”: “String”,
“MinLength”: “1”,
“MaxLength”: “16”,
“AllowedPattern” : "[a-zA-Z][a-zA-Z0-9]"
}
}
YAML
Parameters:
AdminUserAccount:
Default: admin
NoEcho: true
Description: The admin account user name
Type: String
MinLength: 1
MaxLength: 16
AllowedPattern: '[a-zA-Z][a-zA-Z0-9]'
Parameters Section with Number Parameter with MinValue and MaxValue Constraints
The following example depicts a valid Parameters section declaration in which a single Number type parameter is declared. The WebServerPort parameter has a default of 80 and a minimum value 1 and maximum value 65535.
JSON
"Parameters" : {
“WebServerPort”: {
“Default”: “80”,
“Description” : “TCP/IP port for the web server”,
“Type”: “Number”,
“MinValue”: “1”,
“MaxValue”: “65535”
}
}
YAML
Parameters:
WebServerPort:
Default: 80
Description: TCP/IP port for the web server
Type: Number
MinValue: 1
MaxValue: 65535
Parameters Section with Number Parameter with AllowedValues Constraint
The following example depicts a valid Parameters section declaration in which a single Number type parameter is declared. The WebServerPort parameter has a default of 80 and allows only values of 80 and 8888.
JSON
"Parameters" : {
“WebServerPortLimited”: {
“Default”: “80”,
“Description” : “TCP/IP port for the web server”,
“Type”: “Number”,
“AllowedValues” : [“80”, “8888”]
}
}
YAML
Parameters:
WebServerPortLimited:
Default: 80
Description: TCP/IP port for the web server
Type: Number
AllowedValues:
- 80
- 8888
Parameters Section with One Literal CommaDelimitedList Parameter
The following example depicts a valid Parameters section declaration in which a single CommaDelimitedList type parameter is declared. The NoEcho property is set to TRUE, which will mask its value with asterisks (*****) in the aws cloudformation describe-stacks output.
Important
Rather than embedding sensitive information directly in your AWS CloudFormation templates, we strongly suggest you do one of the following:
Use input parameters to pass in information whenever you create or update a stack, using the NoEcho property to obfuscate the parameter value.
Use dynamic parameters in the stack template to reference sensitive information that is stored and managed outside of CloudFormation, such as in the Systems Manager Parameter Store or Secrets Manager.
For more information, see the Do Not Embed Credentials in Your Templates best practice.
JSON
"Parameters" : {
“UserRoles” : {
“Type” : “CommaDelimitedList”,
“Default” : “guest,newhire”,
“NoEcho” : “TRUE”
}
}
YAML
Parameters:
UserRoles:
Type: CommaDelimitedList
Default: "guest,newhire"
NoEcho: true
Parameters Section with Parameter Value Based on Pseudo Parameter
The following example shows commands in the EC2 user data that use the pseudo parameters AWS::StackName and AWS::Region. For more information about pseudo parameters, see Pseudo Parameters Reference.
JSON
"UserData" : { “Fn::Base64” : { “Fn::Join” : ["", [
"#!/bin/bash -xe\n",
“yum install -y aws-cfn-bootstrap\n”,
"/opt/aws/bin/cfn-init -v ",
" --stack ", { "Ref" : "AWS::StackName" },
" --resource LaunchConfig ",
" --region ", { "Ref" : "AWS::Region" }, "\n",
"/opt/aws/bin/cfn-signal -e $? ",
" --stack ", { "Ref" : "AWS::StackName" },
" --resource WebServerGroup ",
" --region ", { "Ref" : "AWS::Region" }, "\n"
]]}}
}
YAML
UserData:
Fn::Base64: !Sub |
#!/bin/bash -xe
yum update -y aws-cfn-bootstrap
/opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource LaunchConfig --region ${AWS::Region}
/opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource WebServerGroup --region ${AWS::Region}
Mapping Section with Three Mappings
The following example depicts a valid Mapping section declaration that contains three mappings. The map, when matched with a mapping key of Stop, SlowDown, or Go, provides the RGB values assigned to the corresponding RGBColor attribute.
JSON
"Mappings" : {
“LightColor” : {
“Stop” : {
“Description” : “red”,
“RGBColor” : “RED 255 GREEN 0 BLUE 0”
},
“SlowDown” : {
“Description” : “yellow”,
“RGBColor” : “RED 255 GREEN 255 BLUE 0”
},
“Go” : {
“Description” : “green”,
“RGBColor” : “RED 0 GREEN 128 BLUE 0”
}
}
}
YAML
Mappings:
LightColor:
Stop:
Description: red
RGBColor: "RED 255 GREEN 0 BLUE 0"
SlowDown:
Description: yellow
RGBColor: "RED 255 GREEN 255 BLUE 0"
Go:
Description: green
RGBColor: "RED 0 GREEN 128 BLUE 0"
Description Based on Literal String
The following example depicts a valid Description section declaration where the value is based on a literal string. This snippet can be for templates, parameters, resources, properties, or outputs.
JSON
"Description" : "Replace this value"
YAML
Description: "Replace this value"
Outputs Section with One Literal String Output
This example shows a output assignment based on a literal string.
JSON
"Outputs" : {
“MyPhone” : {
“Value” : “Please call 555-5555”,
“Description” : “A random message for aws cloudformation describe-stacks”
}
}
YAML
Outputs:
MyPhone:
Value: Please call 555-5555
Description: A random message for aws cloudformation describe-stacks
Outputs Section with One Resource Reference and One Pseudo Reference Output
This example shows an Outputs section with two output assignments. One is based on a resource, and the other is based on a pseudo reference.
JSON
“Outputs” : {
“SNSTopic” : { “Value” : { “Ref” : “MyNotificationTopic” } },
“StackName” : { “Value” : { “Ref” : “AWS::StackName” } }
}
YAML
Outputs:
SNSTopic:
Value: Ref: MyNotificationTopic
StackName:
Value: Ref: AWS::StackName
Outputs Section with an Output Based on a Function, a Literal String, a Reference, and a Pseudo Parameter
This example shows an Outputs section with one output assignment. The Join function is used to concatenate the value, using a percent sign as the delimiter.
JSON
"Outputs" : {
“MyOutput” : {
“Value” : { “Fn::Join” :
[ “%”, [ “A-string”, {“Ref” : “AWS::StackName” } ] ]
}
}
}
YAML
Outputs:
MyOutput:
Value: !Join [ %, [ ‘A-string’, !Ref ‘AWS::StackName’ ]]
Template Format Version
The following snippet depicts a valid Template Format Version section declaration.
JSON
"AWSTemplateFormatVersion" : "2010-09-09"
YAML
AWSTemplateFormatVersion: '2010-09-09’
AWS Tag Property
This example shows an AWS Tag property. You would specify this property within the Properties section of a resource. When the resource is created, it will be tagged with the tags you declare.
Key: "keyname1"
Value: "value1"
