Configuration Options

The serverless CA is highly configurable by adjusting values of Terraform variables in variables.tf. Principal configuration options:

Revocation and GitOps

By default, certificate revocation and GitOps are disabled. If you followed the Getting Started guide you'll already have enabled GitOps: * add a subdirectory to your repository with the same name as the value of the Terraform variable env, e.g. dev, prd add files and subdirectory following the rsa-public-crl example * change the value of Terraform variable cert_info_files to ["tls", "revoked", "revoked-root-ca"] * apply Terraform * you can now revoke a certificate as described in Revocation

Public CRL and CA certs

See details in Revocation and CA Cert Locations.

Default setting: not enabled

CA key algorithms

The following algorithms can be selected via Terraform variables: RSA_2048, RSA_3072, RSA_4096, ECC_NIST_P256, ECC_NIST_P384, ECC_NIST_P521

Default setting: ECC_NIST_P384 (Root CA), ECC_NIST_P256 (Issuing CA)

CloudWatch log subscription filters

CloudWatch log subscription filters can be used to send log events to a central S3 log bucket, from which they can be forwarded to a SIEM.

Default setting: not enabled

CRL publication frequency

To avoid certificate validation errors, it's essential that the CRL publication interval is less than, or equal to, the CRL lifetime. This ensures there is always a valid CRL at any time. * CRLs are published once every 24 hours by default * CRLs can be published manually by executing the CA Step Function * Issuing CA and Root CA CRLs are publised at the same time * Publication frequency can be changed using the Terraform variable schedule_expression * Generally there should be no need to change this value from the default

Default setting: once per day at 08:15 a.m.

CRL lifetime

To avoid certificate validation errors, it's essential that the CRL lifetime is equal to, or greater than, the publication interval. This ensures there is always a valid CRL at any time. * Issuing CA CRL lifetime can be adjusted using the Terraform variables issuing_crl_days and issuing_crl_seconds * issuing_crl_days should normally be identical to the interval configured in schedule_expression * issuing_crl_seconds is an additional time period used as an overlap in case of clock skew * Similarly, Root CA CRL lifetime can be adjusted using the Terraform variables root_crl_days and root_crl_seconds * Generally there should be no need to change these values from their defaults

Default setting (Issuing and Root CA CRLs): 1 day with a 600 second overlap period