Resolution: Cannot Reproduce
centos 8 on esxi 6.7
on a fresh install of Centos 8
deployed guacamole, guacd and mysql docker containers using following command line
docker run --name infra2020-mysql -e MYSQL_ROOT_PASSWORD='xxx' -e MYSQL_DATABASE=guacdb -e MYSQL_USER=guacdb -e MYSQL_PASSWORD=yyyy -d mysql docker run --name infra2020-guacd -e GUACD_LOG_LEVEL=debug -d guacamole/guacd docker run --name infra2020-guacamole --link infra2020-guacd:guacd --link infra2020-mysql:mysql -e MYSQL_DATABASE=guacdb -e MYSQL_USER=guacdb -e MYSQL_PASSWORD=yyyy -d -p 8080:8080 guacamole/guacamole
all containers start well, initdb.sql was properly executed (i have checked into the tables)
mysql guacdb database can be accessed through command line
mysql -h 172.17.0.4 --protocol=tcp -u guacdb -pyyyy -D guacdb Mysql> select * from guacamole_user_permission ; 3 rows in set (0.01 sec)
but when i tried to connect to the guacamole client, i got the follow error displayed in the browser
"An error has occurred and this action cannot be completed. If the problem persists, please notify your system administrator or check your system logs."
and the only log available is the guacamole container (extract from docker logs)
13:04:17.774 [http-nio-8080-exec-2] WARN o.a.g.e.AuthenticationProviderFacade - The "mysql" authentication provider has encountered an internal error which will halt the authentication process. If this is unexpected or you are the developer of this authentication provider, you may wish to enable debug-level logging. If this is expected and you wish to ignore such failures in the future, please set "skip-if-unavailable: mysql" within your guacamole.properties. 13:04:17.774 [http-nio-8080-exec-2] ERROR o.a.g.rest.RESTExceptionMapper - Unexpected internal error: ### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. ### The error may exist in org/apache/guacamole/auth/jdbc/user/UserMapper.xml ### The error may involve org.apache.guacamole.auth.jdbc.user.UserMapper.selectOne ### The error occurred while executing a query ### Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
i have tested starting the container without link but providing mysql_hostname / port with no more success and same error