WORKERS AHEAD!

You are viewing the development documentation for the Apereo CAS server. The functionality presented here is not officially released yet. This is a work in progress and will be continually updated as development moves forward. You are most encouraged to test the changes presented.

Overview

Enable support for the Automatic Certificate Management Environment (ACME) protocol as specified in RFC 8555. ACME is a protocol that a certificate authority (CA) such as Let’s Encrypt and an applicant can use to automate the process of verification and certificate issuance.

Support is enabled by including the following dependency in the overlay:

<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-acme</artifactId>
    <version>${cas.version}</version>
</dependency>

implementation "org.apereo.cas:cas-server-support-acme:${project.'cas.version'}"

dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-acme"
}

dependencies {
    /*
        The following platform references should be included automatically and are listed here for reference only.

        implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
        implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        
    */
    implementation "org.apereo.cas:cas-server-support-acme"
}

The activation of this module is performed on startup when the CAS server is ready serve http requests. When this module is finished successfully, the domain key pair composed of the key and the certificate (including the full certificate path) will be produced in separate files.

If no account was registered with the CA yet, there will also be a new key as the account key pair.

The CSR file contains the CSR that was used for the certificate order. It is generated for convenience and will not be needed later again. When the certificate is renewed, a new CSR will be generated.

There are two sets of key pairs. One is required for creating and accessing your account and the other is required for encrypting the traffic on your domain(s). It is strongly encouraged to use separate key pairs for account and each of the certificates.

Note
Backup key pairs in a safe place, as you will be locked out from your account if you should ever lose it! There is no way to recover a lost key pair, or regain access to your account when the key is lost.

HTTP Challenge

For the HTTP challenge, CAS server will respond to GET requests at /.well-known/acme-challenge/{token} path. The request is always performed against port 80 and at the root of the domain which means CAS MUST be able to operate at that port and context path to respond to verification challenges.

Configuration

The following settings and properties are available from the CAS configuration catalog:

_{The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.}

cas.acme.domain-chain.location=

The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.domain-chain.location=...

This is the most common form of property configuration that is recognized by CAS, regardless of the actual property source, which might in fact be managed separately outside the CAS environment, by another system or cloud framework.

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    domain-chain: 
      location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.domain-chain.location="..." -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory. Note the placement of the system property which must be specified before the CAS web application is launched.

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_DOMAIN_CHAIN_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.domain-chain.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.domain-csr.location=

The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.domain-csr.location=...

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    domain-csr: 
      location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.domain-csr.location="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_DOMAIN_CSR_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.domain-csr.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.domain-key.location=

The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.domain-key.location=...

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    domain-key: 
      location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.domain-key.location="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_DOMAIN_KEY_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.domain-key.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.user-key.location=

The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.user-key.location=...

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    user-key: 
      location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.user-key.location="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_USER_KEY_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.user-key.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.domains=

List of domains or sub domains that are requesting a certificate renewal.

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.domains=...

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    domains: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.domains="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_DOMAINS="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.domains="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.server-url=acme://letsencrypt.org/staging

Server url to contact, when requesting certificates. Use acme://letsencrypt.org for production.

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.server-url=acme://letsencrypt.org/staging

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    server-url: "acme://letsencrypt.org/staging"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.server-url="acme://letsencrypt.org/staging" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_SERVER_URL="acme://letsencrypt.org/staging"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.server-url="acme://letsencrypt.org/staging"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.terms-of-use-accepted=false

Flag that indicates ACME terms of use has been accepted by the user.

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.terms-of-use-accepted=...

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    terms-of-use-accepted: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.terms-of-use-accepted="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_TERMS_OF_USE_ACCEPTED="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.terms-of-use-accepted="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

_{The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This
flag indicates that the presence of the setting
is not immediately necessary in the end-user CAS configuration, because a default value is assigned or
the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your
configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.}

cas.acme.key-size=2048

Indicate the key length/size used when requesting/generating keys.

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.key-size=2048

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    key-size: "2048"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.key-size="2048" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_KEY_SIZE="2048"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.key-size="2048"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.retry-attempts=3

Number of attempts to retry when executing certificate orders or checking for status of an existing order or challenge acknowledgement.

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.retry-attempts=3

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    retry-attempts: "3"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.retry-attempts="3" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_RETRY_ATTEMPTS="3"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.retry-attempts="3"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.acme.retry-internal=PT2S

Delay interval between to retry attempts when executing certificate orders or checking for status of an existing order or challenge acknowledgement.

This settings supports the java.time.Duration syntax ^[?].

org.apereo.cas.configuration.model.support.acme.AcmeProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.acme.retry-internal=PT2S

CAS properties can be specified using the YAML syntax:

cas: 
  acme: 
    retry-internal: "PT2S"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.acme.retry-internal="PT2S" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_ACME_RETRY_INTERNAL="PT2S"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.acme.retry-internal="PT2S"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

Note

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.