AWS Certificate Manager Construct Library

AWS Certificate Manager (ACM) handles the complexity of creating, storing, and renewing public and private SSL/TLS X.509 certificates and keys that protect your AWS websites and applications. ACM certificates can secure singular domain names, multiple specific domain names, wildcard domains, or combinations of these. ACM wildcard certificates can protect an unlimited number of subdomains.

This package provides Constructs for provisioning and referencing ACM certificates which can be used with CloudFront and ELB.

After requesting a certificate, you will need to prove that you own the domain in question before the certificate will be granted. The CloudFormation deployment will wait until this verification process has been completed.

Because of this wait time, when using manual validation methods, it’s better to provision your certificates either in a separate stack from your main service, or provision them manually and import them into your CDK application.

Note: There is a limit on total number of ACM certificates that can be requested on an account and region within a year. The default limit is 2000, but this limit may be (much) lower on new AWS accounts. See https://docs.aws.amazon.com/acm/latest/userguide/acm-limits.html for more information.

DNS validation

DNS validation is the preferred method to validate domain ownership, as it has a number of advantages over email validation. See also Validate with DNS in the AWS Certificate Manager User Guide.

If Amazon Route 53 is your DNS provider for the requested domain, the DNS record can be created automatically:

my_hosted_zone = route53.HostedZone(self, "HostedZone",
    zone_name="example.com"
)
acm.Certificate(self, "Certificate",
    domain_name="hello.example.com",
    certificate_name="Hello World Service",  # Optionally provide an certificate name
    validation=acm.CertificateValidation.from_dns(my_hosted_zone)
)

If Route 53 is not your DNS provider, the DNS records must be added manually and the stack will not complete creating until the records are added.

acm.Certificate(self, "Certificate",
    domain_name="hello.example.com",
    validation=acm.CertificateValidation.from_dns()
)

When working with multiple domains, use the CertificateValidation.fromDnsMultiZone():

example_com = route53.HostedZone(self, "ExampleCom",
    zone_name="example.com"
)
example_net = route53.HostedZone(self, "ExampleNet",
    zone_name="example.net"
)

cert = acm.Certificate(self, "Certificate",
    domain_name="test.example.com",
    subject_alternative_names=["cool.example.com", "test.example.net"],
    validation=acm.CertificateValidation.from_dns_multi_zone({
        "test.example.com": example_com,
        "cool.example.com": example_com,
        "test.example.net": example_net
    })
)

Email validation

Email-validated certificates (the default) are validated by receiving an email on one of a number of predefined domains and following the instructions in the email.

See Validate with Email in the AWS Certificate Manager User Guide.

acm.Certificate(self, "Certificate",
    domain_name="hello.example.com",
    validation=acm.CertificateValidation.from_email()
)

Cross-region Certificates

ACM certificates that are used with CloudFront – or higher-level constructs which rely on CloudFront – must be in the us-east-1 region. CloudFormation allows you to create a Stack with a CloudFront distribution in any region. In order to create an ACM certificate in us-east-1 and reference it in a CloudFront distribution is a different region, it is recommended to perform a multi stack deployment.

Enable the Stack property crossRegionReferences in order to access the cross stack/region certificate.

This feature is currently experimental

from aws_cdk import aws_cloudfront as cloudfront, aws_cloudfront_origins as origins
# app: App


stack1 = Stack(app, "Stack1",
    env=Environment(
        region="us-east-1"
    ),
    cross_region_references=True
)
cert = acm.Certificate(stack1, "Cert",
    domain_name="*.example.com",
    validation=acm.CertificateValidation.from_dns(PublicHostedZone.from_hosted_zone_id(stack1, "Zone", "ZONE_ID"))
)

stack2 = Stack(app, "Stack2",
    env=Environment(
        region="us-east-2"
    ),
    cross_region_references=True
)

cloudfront.Distribution(stack2, "Distribution",
    default_behavior=cloudfront.BehaviorOptions(
        origin=origins.HttpOrigin("example.com")
    ),
    domain_names=["dev.example.com"],
    certificate=cert
)

Requesting private certificates

AWS Certificate Manager can create private certificates issued by Private Certificate Authority (PCA). Validation of private certificates is not necessary.

import aws_cdk.aws_acmpca as acmpca


acm.PrivateCertificate(self, "PrivateCertificate",
    domain_name="test.example.com",
    subject_alternative_names=["cool.example.com", "test.example.net"],  # optional
    certificate_authority=acmpca.CertificateAuthority.from_certificate_authority_arn(self, "CA", "arn:aws:acm-pca:us-east-1:123456789012:certificate-authority/023077d8-2bfa-4eb0-8f22-05c96deade77"),
    key_algorithm=acm.KeyAlgorithm.RSA_2048
)

Requesting certificates without transparency logging

Transparency logging can be opted out of for AWS Certificate Manager certificates. See opting out of certificate transparency logging for limits.

acm.Certificate(self, "Certificate",
    domain_name="test.example.com",
    transparency_logging_enabled=False
)

Key Algorithms

To specify the algorithm of the public and private key pair that your certificate uses to encrypt data use the keyAlgorithm property.

Algorithms supported for an ACM certificate request include:

RSA_2048
EC_prime256v1
EC_secp384r1

acm.Certificate(self, "Certificate",
    domain_name="test.example.com",
    key_algorithm=acm.KeyAlgorithm.EC_PRIME256V1
)

Visit Key algorithms for more details.

Importing

If you want to import an existing certificate, you can do so from its ARN:

arn = "arn:aws:..."
certificate = acm.Certificate.from_certificate_arn(self, "Certificate", arn)

Metrics

The DaysToExpiry metric is available via the metricDaysToExpiry method for all certificates. This metric is emitted by AWS Certificates Manager once per day until the certificate has effectively expired.

An alarm can be created to determine whether a certificate is soon due for renewal ussing the following code:

import aws_cdk.aws_cloudwatch as cloudwatch

# my_hosted_zone: route53.HostedZone

certificate = acm.Certificate(self, "Certificate",
    domain_name="hello.example.com",
    validation=acm.CertificateValidation.from_dns(my_hosted_zone)
)
certificate.metric_days_to_expiry().create_alarm(self, "Alarm",
    comparison_operator=cloudwatch.ComparisonOperator.LESS_THAN_THRESHOLD,
    evaluation_periods=1,
    threshold=45
)