guacd is the native server-side proxy used by the Apache Guacamole web application. If you wish to deploy Guacamole, or an application using the Guacamole core APIs, you will need a copy of guacd running.
docker run --name some-guacd -d guacamole/guacd
guacd will be listening on port 4822, but this port will only be available to Docker containers that have been explicitly linked to some-guacd.
docker run --name some-guacd -d -p 4822:4822 guacamole/guacd
guacd will be listening on port 4822, and Docker will expose this port on the same server hosting Docker. Other services, such as an instance of Tomcat running outside of Docker, will be able to connect to guacd.
Beware of the security ramifications of doing this. There is no authentication within guacd, so allowing access from untrusted applications is dangerous. If you need to expose guacd, ensure that you only expose it as absolutely necessary, and that only specific trusted applications have access.
docker run --name some-app --link some-guacd:guacd -d application-that-uses-guacd
Please report any bugs encountered by opening a new issue in our JIRA.