Instructions copied from MDL-75479 . Prerequisites Docker Your local site is running on http://localhost (or you can forward ports from your site to the CAS container). Don't use container for running moodle, just mdk is fine Avoid testing with with Docker running on M1 Mac/ARM system Testing instructions Run the docker CAS container: docker run --rm --name cas -p 8080:8080 -p 8443:8443 -dt moodlehq/moodle-docker-cas:dev Since the CAS container is accessed via localhost, set $CFG->wwwroot in config.php to a different value (e.g. by using ngrok) Login as admin to your site Open Site admin => Plugins => Authentication => Manage authentication Edit the settings for CAS server (SSO) Set the following: Hostname: localhost Base URI: cas/ Port: 8443 Multi-authentication: Yes Save changes Enable CAS server (SSO) If you have an existing user with username 's10' delete it Create a new user with: Username: s10 Authentication method CAS Server (SSO) Open a private browsing window and navigate to the site Click Log in Click the "Log in using your account on: CAS" button Note: You may have to ignore the certificate being invalid. Generally this is under "Advanced" and then there's a link to "Proceed". This is just because we're using a testing image with a self-generated SSL certificate Login into the CAS server with username " s10 " and password " test " Confirm you were logged into Moodle as the new user Stop the docker container docker stop cas