This documentation assumes that you already have access to a SQL Server database, either on a server of your own or hosted elsewhere, and that Guacamole has already been installed using Glyptodon Enterprise. If you do not already a SQL Server database ready, please set up SQL Server before proceeding. If you do not already have Guacamole installed, please see the quickstart guide.

Installing SQL Server support for Guacamole

Glyptodon Enterprise packages Guacamole’s SQL Server support within the glyptodon-guacamole-auth-jdbc-sqlserver package. This package must be installed before creating Guacamole’s database within SQL Server, as it includes the SQL scripts necessary for doing so:

$ sudo yum install glyptodon-guacamole-auth-jdbc-sqlserver

Creating and initializing the Guacamole database

If you haven’t already done so, a database specific to Guacamole needs to be created within SQL Server. The database can be called anything you like and there are no specific requirements for the size of the database, collation, etc.; all that matters is that the database be dedicated to Guacamole, and not shared by different applications:

CREATE DATABASE guacamole_db;
GO

Guacamole will not automatically initialize the database with the required schema. You will need to do this yourself using the SQL scripts provided with the glyptodon-guacamole-auth-jdbc-sqlserver package, which are located within the /usr/share/guacamole-auth-jdbc-sqlserver/schema directory:

FilenameDescription
001-create-schema.sqlCreates all tables and indexes which are required for the SQL Server authentication extension to function.
002-create-admin-user.sqlCreates a default administrative user, “guacadmin”, with password “guacadmin”. These credentials will need to be changed once SQL Server authentication is confirmed to be working.

The above scripts must be run in sequence. The first script, 001-create-schema.sql, creates the database schema:

$ sqlcmd -S sqlserver_database_hostname -U sa -d guacamole_db -i /usr/share/guacamole-auth-jdbc-sqlserver/schema/001-create-schema.sql

The second script, 002-create-admin-user.sql, defines a default administrative user and can only successfully run if the tables created by the first script exist:

$ sqlcmd -S sqlserver_database_hostname -U sa -d guacamole_db -i /usr/share/guacamole-auth-jdbc-sqlserver/schema/002-create-admin-user.sql

Creating a Database User for Guacamole

To execute queries against the database, Guacamole will need its own database user with sufficient privileges. Because Guacamole does not automatically apply or update its own schema, the required privileges are minimal, dealing only with creation and maintenance of data within already-defined tables and indexes. Permission to SELECT, INSERT, UPDATE, and DELETE from all tables in the database is sufficient and exactly covered by SQL Server's db_datareader and db_datawriter roles.

The login to be used by Guacamole must use SQL Server authentication, with a password which will eventually be stored within /etc/guacamole/guacamole.properties:

CREATE LOGIN guacamole_user WITH PASSWORD = 'some_password';
GO

The login must then be associated with a user specific to the Guacamole database:

CREATE USER guacamole_user;
GO

To grant the necessary SELECT, INSERT, UPDATE, and DELETE permissions for all tables in the Guacamole database, the user must be added to the database's db_datareader and db_datawriter roles:

ALTER ROLE db_datawriter ADD MEMBER guacamole_user;
ALTER ROLE db_datareader ADD MEMBER guacamole_user;
GO

Connecting Guacamole to SQL Server

Once the database and database user have been prepared, Guacamole’s main configuration file, /etc/guacamole/guacamole.properties, must be modified to specify the credentials of that user and to point the SQL Server instance and database:

$ sudo vi /etc/guacamole/guacamole.properties

The guacamole.properties file provided with Glyptodon Enterprise is organized into sections documented with blocks of comments and example properties. The first section which must be modified is marked “JDBC-1” and defines the TCP connection information for the database in use. Uncomment the sqlserver-hostname and sqlserver-port properties, modifying their values to point to your instance of SQL Server:

##
## [JDBC-1] Database TCP connection information
##
## The TCP connection details for the PostgreSQL, MySQL / MariaDB, or SQL
## Server database.
##

#mysql-hostname: localhost
#mysql-port:     3306

#postgresql-hostname: localhost
#postgresql-port:     5432

sqlserver-hostname: localhost
sqlserver-port:     1433

The “JDBC-2” section, which defines the database name and associated credentials, must also be modified to specify the correct database name, username, and password. These values are given with the sqlserver-database, sqlserver-username, and sqlserver-password properties respectively:

##
## [JDBC-2] Database name and credentials
##
## The name of the database to use, as well as the credentials to use when
## connecting to the database. THESE PROPERTIES ARE REQUIRED if one of the
## database authentication extensions will be used.
##

#mysql-database: guacamole_db
#mysql-username: guacamole_user
#mysql-password: some_password

#postgresql-database: guacamole_db
#postgresql-username: guacamole_user
#postgresql-password: some_password

sqlserver-database: guacamole_db
sqlserver-username: guacamole_user
sqlserver-password: some_password

Completing installation

Guacamole will generally only load new extensions and reread guacamole.properties during the startup process. To apply the configuration changes, Guacamole (and thus Tomcat) must be restarted:

$ sudo systemctl restart tomcat

If you are using SELinux (the default on both CentOS and RHEL), you must also configure SELinux to allow Tomcat to connect to the database over the network:

$ sudo setsebool -P tomcat_can_network_connect_db 1

To make sure everything is working as expected, you should also visit your Guacamole instance with a web browser (most likely at http://HOSTNAME:8080/guacamole/, where “HOSTNAME” is the hostname or IP address of your server). If all is working correctly, you should see a login screen with a username/password prompt, and you will be able to log in using the default account created with the 002-create-admin-user.sql script:

Username:guacadmin
Password:guacadmin

If Guacamole is not accessible after the Tomcat service has been restarted, verify that you have indeed configured SELinux to allow Tomcat to connect to the database and check the SELinux audit logs (/var/log/audit/audit.log) for AVC denials.

Once you have verified that you can log in successfully, you should immediately change the password, as keeping default accounts unchanged is dangerous. While logged into Guacamole, you can access the built-in password changing interface by clicking on your username in the upper-right corner of the screen and selecting “Settings”.