From the project page:

Notes:

Unresolved bugs

Requirements installation

Note: in this example the password is "some_password", change it accordingly.

Create the required directories:

# mkdir -p /etc/guacamole/lib /etc/guacamole/extensions

Install Tomcat 8 application server and MariaDB server:

# apt install tomcat8 mariadb-server -y

Complete the initial database configuration:

# mysql_secure_installation

(follow the script prompts)

Create the Guacamole database, setup its permissions:

# mysql -u root -p
Enter password: ***
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 233
Server version: 5.5.29-0ubuntu0.12.10.1 (Ubuntu)

Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> CREATE DATABASE guacamole_db; 
Query OK, 1 row affected (0.00 sec)

mysql> CREATE USER 'guacamole_user'@'localhost' IDENTIFIED BY 'some_password';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT SELECT,INSERT,UPDATE,DELETE ON guacamole_db.* TO 'guacamole_user'@'localhost';
Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.02 sec)

mysql> quit;
Bye

Install the Java database (JDBC) driver for MySQL / MariaDB, link it from the Guacamole configuration:

# apt install libmysql-java
# ln -s /usr/share/java/mysql-connector-java.jar /etc/guacamole/lib/

Download the JDBC Guacamole authentication component and copy it to the appropriate location:

# wget -c  https://sourceforge.net/projects/guacamole/files/current/extensions/guacamole-auth-jdbc-0.9.9.tar.gz
# tar -xzvf guacamole-auth-jdbc-0.9.9.tar.gz
# mv guacamole-auth-jdbc-0.9.9/mysql/guacamole-auth-jdbc-mysql-0.9.9.jar /etc/guacamole/extensions

Use the database scripts to populate the database with the initial application data (first "guacadmin user", etc.):

# ls guacamole-auth-jdbc-0.9.9/mysql/schema/
001-create-schema.sql  002-create-admin-user.sql  upgrade
# cat guacamole-auth-jdbc-0.9.9/mysql/schema/*.sql | mysql -u root -p guacamole_db

Application installation

Guacamole server, from Debian packages (v 0.9.9)

Install the Guacamole server:

# apt install guacd -y

Guacamole server, from sources (v 0.9.14)

This is required if you want to use PKA in SSH connections (see above, Unresolved bugs).

# apt-get install libcairo2-dev libossp-uuid-dev libavcodec-dev libavutil-dev libswscale-dev libfreerdp-dev libpango1.0-dev libssh2-1-dev libtelnet-dev libvncserver-dev libpulse-dev libssl-dev libvorbis-dev libwebp-dev libjpeg62-turbo-dev libpng-dev libpng16-16 git

# git clone git://github.com/apache/incubator-guacamole-server.git
autoreconf -fi
./configure --with-init-dir=/etc/init.d
# make && make install
# ldconfig
# systemctl enable guacd
# /etc/init.d/guacd start

If you had initially installed an older version don't forget to also update the corresponding guacamole-auth-jdbc, guacamole.war and also update the database - see "If you are upgrading from an older version of Guacamole..." as indicated in the official documentation.

Configuration files

Create the configuration file and link the configuration directory from the Tomcat setup:

# touch /etc/guacamole/guacamole.properties

Add this information to the guacamole.properties configuration file:

# Hostname and port of guacamole proxy
guacd-hostname: localhost
guacd-port:     4822

# MySQL properties
mysql-hostname: localhost
mysql-port: 3306
mysql-database: guacamole_db
mysql-username: guacamole_user
mysql-password: some_password

Link the guacamole.properties file to your Tomcat setup:

# ln -s /etc/guacamole/ /var/lib/tomcat8/.guacamole

Get the Guacamole web application:

# wget https://sourceforge.net/projects/guacamole/files/current/binary/guacamole-0.9.9.war

The file is about 7M big, consider checking its MD5 checksum to see if it matches the one below:

# md5sum guacamole-0.9.9.war
324c17aa305a077a2127378a2d0a7a51  guacamole-0.9.9.war

Copy it to Tomcat for deployment and restart Tomcat:

# mv guacamole-0.9.9.war /var/lib/tomcat8/webapps/guacamole.war
# service tomcat8 restart

Note: using a more recent version of the Guacamole web application (.war file) may work with Debian's Guacamole server (guacd) v. 0.9.9 but is not recommended or supported.

You can now access the application at http://<youserverip>:8080/guacamole. The default user and password are both "guacadmin".