Sintaxis de Rules de la plantilla de CloudFormation
La sección Rules
es una parte opcional de una plantilla de CloudFormation que permite una lógica de validación personalizada. Cuando se incluye, esta sección contiene funciones de reglas que validan los valores de los parámetros antes de que CloudFormation cree o actualice cualquier recurso.
Las reglas son útiles cuando las restricciones estándar de los parámetros son insuficientes. Por ejemplo, cuando SSL está habilitado, se debe proporcionar tanto un certificado como un nombre de dominio. Una regla puede garantizar que se cumplan estas dependencias.
Sintaxis
La sección Rules
usa la siguiente sintaxis:
JSON
La sección Rules
de una plantilla consta del nombre de clave Rules
, seguido de un único signo de dos puntos. Debe utilizar llaves para incluir todas las declaraciones de reglas. Si se declaran varias reglas, deben delimitarse mediante comas. Para cada regla, se declara un nombre lógico entre comillas seguido de un signo de dos puntos y de las llaves que contienen la condición de regla y las declaraciones.
{
"Rules": {
"LogicalRuleName1
": {
"RuleCondition": {
"rule-specific intrinsic function
": "Value
"
},
"Assertions": [
{
"Assert": {
"rule-specific intrinsic function
": "Value
"
},
"AssertDescription": "Information about this assert
"
},
{
"Assert": {
"rule-specific intrinsic function
": "Value
"
},
"AssertDescription": "Information about this assert
"
}
]
},
"LogicalRuleName2
": {
"Assertions": [
{
"Assert": {
"rule-specific intrinsic function
": "Value
"
},
"AssertDescription": "Information about this assert
"
}
]
}
}
}
YAML
Rules:
LogicalRuleName1
:
RuleCondition:
rule-specific intrinsic function
: Value
Assertions:
- Assert:
rule-specific intrinsic function
: Value
AssertDescription: Information about this assert
- Assert:
rule-specific intrinsic function
: Value
AssertDescription: Information about this assert
LogicalRuleName2
:
Assertions:
- Assert:
rule-specific intrinsic function
: Value
AssertDescription: Information about this assert
Campos de reglas
La sección Rules
puede incluir los siguientes campos.
- ID lógico (también denominado nombre lógico)
-
Un identificador único para cada regla.
RuleCondition
(opcional)-
Una propiedad que determina cuándo surte efecto una regla. Si no se define la condición de regla, las declaraciones de la regla surten efecto en todos los casos. Para cada regla, sólo puede definir una condición de regla.
Assertions
(obligatorio)-
Una o más declaraciones que especifican los valores aceptables para un parámetro determinado.
Assert
-
Una condición que se debe evaluar como
true
. AssertDescription
-
Un mensaje que se muestra cuando falla una aserción.
Funciones intrínsecas específicas de la regla
Para definir sus reglas, debe utilizar funciones específicas de reglas, que son funciones que solo se pueden utilizar en la sección Rules
de una plantilla. Puede anidar funciones, pero el resultado final de una condición de regla o una declaración debe ser true
o false
.
Ahora están disponibles las siguientes funciones de reglas:
Estas funciones intrínsecas se utilizan en la condición o aserciones de una regla. La propiedad de condición determina si CloudFormation aplicará las declaraciones. Si la condición se evalúa como true
, CloudFormation evalúa las declaraciones para comprobar si el valor de un parámetro es válido en el momento de crear o actualizar un producto provisionado. Si el valor de un parámetro no es válido, CloudFormation no crea o actualizar la pila. Si la condición se evalúa como false
, CloudFormation no comprueba el valor del parámetro y procede a llevar a cabo la operación de la pila.
Ejemplos
Comprobación condicional del valor de un parámetro
En el siguiente ejemplo, las dos reglas comprueban el valor del InstanceType
parámetro. En función del valor del parámetro entorno (test
o prod
), el usuario debe especificar a1.medium
o a1.large
para el parámetro InstanceType
. Los parámetros InstanceType
y Environment
deben declararse en la sección Parameters
de la misma plantilla.
JSON
{ "Rules": { "testInstanceType": { "RuleCondition": { "Fn::Equals": [ {"Ref": "Environment"}, "test" ] }, "Assertions": [ { "Assert": { "Fn::Contains": [ ["a1.medium"], {"Ref": "InstanceType"} ] }, "AssertDescription": "For a test environment, the instance type must be a1.medium" } ] }, "prodInstanceType": { "RuleCondition": { "Fn::Equals": [ {"Ref": "Environment"}, "prod" ] }, "Assertions": [ { "Assert": { "Fn::Contains": [ ["a1.large"], {"Ref": "InstanceType"} ] }, "AssertDescription": "For a production environment, the instance type must be a1.large" } ] } } }
YAML
Rules: testInstanceType: RuleCondition: !Equals - !Ref Environment - test Assertions: - Assert: 'Fn::Contains': - - a1.medium - !Ref InstanceType AssertDescription: 'For a test environment, the instance type must be a1.medium' prodInstanceType: RuleCondition: !Equals - !Ref Environment - prod Assertions: - Assert: 'Fn::Contains': - - a1.large - !Ref InstanceType AssertDescription: 'For a production environment, the instance type must be a1.large'
Validación de parámetros cruzados
Las siguientes plantillas de ejemplo demuestran el uso de reglas para las validaciones entre parámetros. Crean un sitio web de ejemplo que se ejecuta en un grupo de escalado automático detrás de un equilibrador de carga. El sitio web está disponible en los puertos 80 o 443, según los parámetros de entrada. Las instancias del grupo de escalado automático se pueden configurar para que escuchen en cualquier puerto (con 8888 como el valor predeterminado).
Las reglas de esta plantilla validan los parámetros de entrada antes de crear la pila. Comprueban que todas las subredes pertenecen a la VPC especificada y garantizan que, cuando el parámetro UseSSL
se establece en Yes
, se proporcionen un ARN de certificado SSL y un nombre de zona alojada.
nota
Se le facturarán los recursos de AWS que utilice si crea una pila a partir de esta plantilla.
JSON
{ "AWSTemplateFormatVersion": "2010-09-09", "Parameters": { "VpcId": { "Type": "AWS::EC2::VPC::Id", "Description": "VpcId of your existing Virtual Private Cloud (VPC)", "ConstraintDescription": "must be the VPC Id of an existing Virtual Private Cloud." }, "Subnets": { "Type": "List<AWS::EC2::Subnet::Id>", "Description": "The list of SubnetIds in your Virtual Private Cloud (VPC)", "ConstraintDescription": "must be a list of at least two existing subnets associated with at least two different availability zones." }, "InstanceType": { "Description": "WebServer EC2 instance type", "Type": "String", "Default": "t2.micro", "AllowedValues": ["t2.micro", "t3.micro"], "ConstraintDescription": "must be a valid EC2 instance type." }, "KeyName": { "Description": "Name of an existing EC2 KeyPair to enable SSH access to the instances", "Type": "AWS::EC2::KeyPair::KeyName", "ConstraintDescription": "must be the name of an existing EC2 KeyPair." }, "SSHLocation": { "Description": "The IP address range that can be used to SSH to the EC2 instances", "Type": "String", "MinLength": "9", "MaxLength": "18", "Default": "0.0.0.0/0", "AllowedPattern": "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})/(\\d{1,2})", "ConstraintDescription": "must be a valid IP CIDR range of the form x.x.x.x/x." }, "UseSSL": { "AllowedValues": ["Yes", "No"], "Default": "No", "Description": "Select \"Yes\" to implement SSL, \"No\" to skip (default).", "Type": "String" }, "ALBSSLCertificateARN": { "Default": "", "Description": "[Optional] The ARN of the SSL certificate to be used for the Application Load Balancer", "Type": "String" }, "HostedZoneName": { "AllowedPattern": "^$|(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\\-]*[a-zA-Z0-9])\\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\\-]*[A-Za-z0-9])$", "Default": "", "Description": "[Optional] The domain name of a valid Hosted Zone on AWS.", "Type": "String" } }, "Conditions": { "UseALBSSL": {"Fn::Equals": [{"Ref": "UseSSL"}, "Yes"]} }, "Rules": { "SubnetsInVPC": { "Assertions": [ { "Assert": {"Fn::EachMemberEquals": [{"Fn::ValueOf": ["Subnets", "VpcId"]}, {"Ref": "VpcId"}]}, "AssertDescription": "All subnets must be in the VPC" } ] }, "ValidateHostedZone": { "RuleCondition": {"Fn::Equals": [{"Ref": "UseSSL"}, "Yes"]}, "Assertions": [ { "Assert": {"Fn::Not": [{"Fn::Equals": [{"Ref": "ALBSSLCertificateARN"}, ""]}]}, "AssertDescription": "ACM Certificate value cannot be empty if SSL is required" }, { "Assert": {"Fn::Not": [{"Fn::Equals": [{"Ref": "HostedZoneName"}, ""]}]}, "AssertDescription": "Route53 Hosted Zone Name is mandatory when SSL is required" } ] } }, "Mappings": { "AWSAMIRegionMap": { "us-east-1": {"AMZNLINUXHVM": "ami-0ff8a91507f77f867"}, "us-west-1": {"AMZNLINUXHVM": "ami-0bdb828fd58c52235"}, "eu-west-1": {"AMZNLINUXHVM": "ami-047bb4163c506cd98"}, "ap-southeast-1": {"AMZNLINUXHVM": "ami-08569b978cc4dfa10"} } }, "Resources": { "WebServerGroup": { "Type": "AWS::AutoScaling::AutoScalingGroup", "Properties": { "VPCZoneIdentifier": {"Ref": "Subnets"}, "LaunchConfigurationName": {"Ref": "LaunchConfig"}, "MinSize": "2", "MaxSize": "2", "TargetGroupARNs": [{"Ref": "ALBTargetGroup"}] }, "CreationPolicy": { "ResourceSignal": {"Timeout": "PT15M"} }, "UpdatePolicy": { "AutoScalingRollingUpdate": { "MinInstancesInService": "1", "MaxBatchSize": "1", "PauseTime": "PT15M", "WaitOnResourceSignals": true } } }, "LaunchConfig": { "Type": "AWS::AutoScaling::LaunchConfiguration", "Metadata": { "Comment": "Install a simple application", "AWS::CloudFormation::Init": { "config": { "packages": {"yum": {"httpd": []}}, "files": { "/var/www/html/index.html": { "content": {"Fn::Join": ["\n", ["<h1>Congratulations, you have successfully launched the AWS CloudFormation sample.</h1>"]]}, "mode": "000644", "owner": "root", "group": "root" }, "/etc/cfn/cfn-hup.conf": { "content": {"Fn::Join": ["", [ "[main]\n", "stack=", {"Ref": "AWS::StackId"}, "\n", "region=", {"Ref": "AWS::Region"}, "\n" ]]}, "mode": "000400", "owner": "root", "group": "root" }, "/etc/cfn/hooks.d/cfn-auto-reloader.conf": { "content": {"Fn::Join": ["", [ "[cfn-auto-reloader-hook]\n", "triggers=post.update\n", "path=Resources.LaunchConfig.Metadata.AWS::CloudFormation::Init\n", "action=/opt/aws/bin/cfn-init -v ", " --stack ", {"Ref": "AWS::StackName"}, " --resource LaunchConfig ", " --region ", {"Ref": "AWS::Region"}, "\n", "runas=root\n" ]]}, "mode": "000400", "owner": "root", "group": "root" } }, "services": { "sysvinit": { "httpd": { "enabled": "true", "ensureRunning": "true" }, "cfn-hup": { "enabled": "true", "ensureRunning": "true", "files": [ "/etc/cfn/cfn-hup.conf", "/etc/cfn/hooks.d/cfn-auto-reloader.conf" ] } } } } } }, "Properties": { "ImageId": {"Fn::FindInMap": ["AWSAMIRegionMap", {"Ref": "AWS::Region"}, "AMZNLINUXHVM"]}, "SecurityGroups": [{"Ref": "InstanceSecurityGroup"}], "InstanceType": {"Ref": "InstanceType"}, "KeyName": {"Ref": "KeyName"}, "UserData": { "Fn::Base64": {"Fn::Join": ["", [ "#!/bin/bash -xe\n", "yum update -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" ]]} } } }, "ELBSecurityGroup": { "Type": "AWS::EC2::SecurityGroup", "Properties": { "GroupDescription": "Allow access to the ELB", "VpcId": {"Ref": "VpcId"}, "SecurityGroupIngress": [{ "Fn::If": [ "UseALBSSL", { "IpProtocol": "tcp", "FromPort": 443, "ToPort": 443, "CidrIp": "0.0.0.0/0" }, { "IpProtocol": "tcp", "FromPort": 80, "ToPort": 80, "CidrIp": "0.0.0.0/0" } ] }] } }, "ApplicationLoadBalancer": { "Type": "AWS::ElasticLoadBalancingV2::LoadBalancer", "Properties": { "Subnets": {"Ref": "Subnets"}, "SecurityGroups": [{"Ref": "ELBSecurityGroup"}] } }, "ALBListener": { "Type": "AWS::ElasticLoadBalancingV2::Listener", "Properties": { "DefaultActions": [{ "Type": "forward", "TargetGroupArn": {"Ref": "ALBTargetGroup"} }], "LoadBalancerArn": {"Ref": "ApplicationLoadBalancer"}, "Port": {"Fn::If": ["UseALBSSL", 443, 80]}, "Protocol": {"Fn::If": ["UseALBSSL", "HTTPS", "HTTP"]}, "Certificates": [{ "Fn::If": [ "UseALBSSL", {"CertificateArn": {"Ref": "ALBSSLCertificateARN"}}, {"Ref": "AWS::NoValue"} ] }] } }, "ALBTargetGroup": { "Type": "AWS::ElasticLoadBalancingV2::TargetGroup", "Properties": { "HealthCheckIntervalSeconds": 30, "HealthCheckTimeoutSeconds": 5, "HealthyThresholdCount": 3, "Port": 80, "Protocol": "HTTP", "UnhealthyThresholdCount": 5, "VpcId": {"Ref": "VpcId"} } }, "InstanceSecurityGroup": { "Type": "AWS::EC2::SecurityGroup", "Properties": { "GroupDescription": "Enable SSH access and HTTP access on the inbound port", "SecurityGroupIngress": [ { "IpProtocol": "tcp", "FromPort": 80, "ToPort": 80, "SourceSecurityGroupId": {"Fn::Select": [0, {"Fn::GetAtt": ["ApplicationLoadBalancer", "SecurityGroups"]}]} }, { "IpProtocol": "tcp", "FromPort": 22, "ToPort": 22, "CidrIp": {"Ref": "SSHLocation"} } ], "VpcId": {"Ref": "VpcId"} } }, "RecordSet": { "Type": "AWS::Route53::RecordSetGroup", "Condition": "UseALBSSL", "Properties": { "HostedZoneName": {"Fn::Join": ["", [{"Ref": "HostedZoneName"}, "."]]}, "RecordSets": [{ "Name": {"Fn::Join": ["", [ {"Fn::Select": ["0", {"Fn::Split": [".", {"Fn::GetAtt": ["ApplicationLoadBalancer", "DNSName"]}]}]}, ".", {"Ref": "HostedZoneName"}, "." ]]}, "Type": "A", "AliasTarget": { "DNSName": {"Fn::GetAtt": ["ApplicationLoadBalancer", "DNSName"]}, "EvaluateTargetHealth": true, "HostedZoneId": {"Fn::GetAtt": ["ApplicationLoadBalancer", "CanonicalHostedZoneID"]} } }] } } }, "Outputs": { "URL": { "Description": "URL of the website", "Value": {"Fn::Join": ["", [ {"Fn::If": [ "UseALBSSL", {"Fn::Join": ["", [ "https://", {"Fn::Join": ["", [ {"Fn::Select": ["0", {"Fn::Split": [".", {"Fn::GetAtt": ["ApplicationLoadBalancer", "DNSName"]}]}]}, ".", {"Ref": "HostedZoneName"}, "." ]]} ]]}, {"Fn::Join": ["", [ "http://", {"Fn::GetAtt": ["ApplicationLoadBalancer", "DNSName"]} ]]} ]} ]]} } } }
YAML
AWSTemplateFormatVersion: 2010-09-09 Parameters: VpcId: Type: AWS::EC2::VPC::Id Description: VpcId of your existing Virtual Private Cloud (VPC) ConstraintDescription: must be the VPC Id of an existing Virtual Private Cloud. Subnets: Type: List<AWS::EC2::Subnet::Id> Description: The list of SubnetIds in your Virtual Private Cloud (VPC) ConstraintDescription: >- must be a list of at least two existing subnets associated with at least two different availability zones. They should be residing in the selected Virtual Private Cloud. InstanceType: Description: WebServer EC2 instance type Type: String Default: t2.micro AllowedValues: - t2.micro - t3.micro ConstraintDescription: must be a valid EC2 instance type. KeyName: Description: Name of an existing EC2 KeyPair to enable SSH access to the instances Type: AWS::EC2::KeyPair::KeyName ConstraintDescription: must be the name of an existing EC2 KeyPair. SSHLocation: Description: The IP address range that can be used to SSH to the EC2 instances Type: String MinLength: '9' MaxLength: '18' Default: 0.0.0.0/0 AllowedPattern: '(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/(\d{1,2})' ConstraintDescription: must be a valid IP CIDR range of the form x.x.x.x/x. UseSSL: AllowedValues: - 'Yes' - 'No' ConstraintDescription: Select Yes to create a HTTPS Listener Default: 'No' Description: 'Select "Yes" to implement SSL, "No" to skip (default).' Type: String ALBSSLCertificateARN: Default: '' Description: >- [Optional] The ARN of the SSL certificate to be used for the Application Load Balancer Type: String HostedZoneName: AllowedPattern: >- ^$|(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$ Default: '' Description: '[Optional] The domain name of a valid Hosted Zone on AWS.' Type: String Conditions: UseALBSSL: !Equals - !Ref UseSSL - 'Yes' Rules: SubnetsInVPC: Assertions: - Assert: 'Fn::EachMemberEquals': - 'Fn::ValueOf': - Subnets - VpcId - Ref: VpcId AssertDescription: All subnets must be in the VPC ValidateHostedZone: RuleCondition: !Equals - !Ref UseSSL - 'Yes' Assertions: - Assert: !Not - !Equals - !Ref ALBSSLCertificateARN - '' AssertDescription: ACM Certificate value cannot be empty if SSL is required - Assert: !Not - !Equals - !Ref HostedZoneName - '' AssertDescription: Route53 Hosted Zone Name is mandatory when SSL is required Mappings: AWSAMIRegionMap: us-east-1: AMZNLINUXHVM: ami-0ff8a91507f77f867 us-west-1: AMZNLINUXHVM: ami-0bdb828fd58c52235 eu-west-1: AMZNLINUXHVM: ami-047bb4163c506cd98 ap-southeast-1: AMZNLINUXHVM: ami-08569b978cc4dfa10 Resources: WebServerGroup: Type: AWS::AutoScaling::AutoScalingGroup Properties: VPCZoneIdentifier: !Ref Subnets LaunchConfigurationName: !Ref LaunchConfig MinSize: '2' MaxSize: '2' TargetGroupARNs: - !Ref ALBTargetGroup CreationPolicy: ResourceSignal: Timeout: PT15M UpdatePolicy: AutoScalingRollingUpdate: MinInstancesInService: '1' MaxBatchSize: '1' PauseTime: PT15M WaitOnResourceSignals: 'true' LaunchConfig: Type: AWS::AutoScaling::LaunchConfiguration Metadata: Comment: Install a simple application 'AWS::CloudFormation::Init': config: packages: yum: httpd: [] files: /var/www/html/index.html: content: !Join - |+ - - >- <h1>Congratulations, you have successfully launched the AWS CloudFormation sample.</h1> mode: '000644' owner: root group: root /etc/cfn/cfn-hup.conf: content: !Sub | [main] stack=${AWS::StackId} region=${AWS::Region} mode: '000400' owner: root group: root /etc/cfn/hooks.d/cfn-auto-reloader.conf: content: !Sub |- [cfn-auto-reloader-hook] triggers=post.update path=Resources.LaunchConfig.Metadata.AWS::CloudFormation::Init action=/opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource LaunchConfig --region ${AWS::Region} runas=root mode: '000400' owner: root group: root services: sysvinit: httpd: enabled: 'true' ensureRunning: 'true' cfn-hup: enabled: 'true' ensureRunning: 'true' files: - /etc/cfn/cfn-hup.conf - /etc/cfn/hooks.d/cfn-auto-reloader.conf Properties: ImageId: !FindInMap - AWSAMIRegionMap - !Ref 'AWS::Region' - AMZNLINUXHVM SecurityGroups: - !Ref InstanceSecurityGroup InstanceType: !Ref InstanceType KeyName: !Ref KeyName UserData: !Base64 Fn::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} ELBSecurityGroup: Type: AWS::EC2::SecurityGroup Properties: GroupDescription: Allow access to the ELB VpcId: !Ref VpcId SecurityGroupIngress: - !If - UseALBSSL - IpProtocol: tcp FromPort: 443 ToPort: 443 CidrIp: 0.0.0.0/0 - IpProtocol: tcp FromPort: 80 ToPort: 80 CidrIp: 0.0.0.0/0 ApplicationLoadBalancer: Type: AWS::ElasticLoadBalancingV2::LoadBalancer Properties: Subnets: !Ref Subnets SecurityGroups: - !Ref ELBSecurityGroup ALBListener: Type: AWS::ElasticLoadBalancingV2::Listener Properties: DefaultActions: - Type: forward TargetGroupArn: !Ref ALBTargetGroup LoadBalancerArn: !Ref ApplicationLoadBalancer Port: !If - UseALBSSL - 443 - 80 Protocol: !If - UseALBSSL - HTTPS - HTTP Certificates: - !If - UseALBSSL - CertificateArn: !Ref ALBSSLCertificateARN - !Ref 'AWS::NoValue' ALBTargetGroup: Type: AWS::ElasticLoadBalancingV2::TargetGroup Properties: HealthCheckIntervalSeconds: 30 HealthCheckTimeoutSeconds: 5 HealthyThresholdCount: 3 Port: 80 Protocol: HTTP UnhealthyThresholdCount: 5 VpcId: !Ref VpcId InstanceSecurityGroup: Type: AWS::EC2::SecurityGroup Properties: GroupDescription: Enable SSH access and HTTP access on the inbound port SecurityGroupIngress: - IpProtocol: tcp FromPort: 80 ToPort: 80 SourceSecurityGroupId: !Select - 0 - !GetAtt - ApplicationLoadBalancer - SecurityGroups - IpProtocol: tcp FromPort: 22 ToPort: 22 CidrIp: !Ref SSHLocation VpcId: !Ref VpcId RecordSet: Type: AWS::Route53::RecordSetGroup Condition: UseALBSSL Properties: HostedZoneName: !Join - '' - - !Ref HostedZoneName - . RecordSets: - Name: !Join - '' - - !Select - '0' - !Split - . - !GetAtt - ApplicationLoadBalancer - DNSName - . - !Ref HostedZoneName - . Type: A AliasTarget: DNSName: !GetAtt - ApplicationLoadBalancer - DNSName EvaluateTargetHealth: true HostedZoneId: !GetAtt - ApplicationLoadBalancer - CanonicalHostedZoneID Outputs: URL: Description: URL of the website Value: !Join - '' - - !If - UseALBSSL - !Join - '' - - 'https://' - !Join - '' - - !Select - '0' - !Split - . - !GetAtt - ApplicationLoadBalancer - DNSName - . - !Ref HostedZoneName - . - !Join - '' - - 'http://' - !GetAtt - ApplicationLoadBalancer - DNSName