Installation of the DOMserver

The DOMjudge server (short DOMserver) is the central entity that runs the DOMjudge web interface and API that teams, jury members and the judgehosts connect to.

Requirements

System requirements

  • The operating system is Linux or another Unix variant. DOMjudge has mostly been tested with Debian and Ubuntu on AMD64, but should work on other environments. See our wiki for information about DOMjudge and WSLv2.

  • It is probably necessary that you have root access to be able to install the necessary components, but it’s not required for actually running the DOMserver.

  • A TCP/IP network which connects the DOMserver and the judgehosts, and DOMjudge and the team workstations. All of these machines only need HTTP(S) access to the DOMserver.

Software requirements

  • A web server with support for PHP >= 8.1.0 and the mysqli, curl, gd, mbstring, intl, zip, xml and json extensions for PHP.

  • MySQL or MariaDB database. This can be on the same machine, but for advanced setups can also run on a dedicated machine.

  • An NTP daemon, for keeping the clocks between jury system and team workstations in sync.

For your convenience, the following command will install the necessary software on the DOMjudge server as mentioned above when using Debian GNU/Linux, or one of its derivative distributions like Ubuntu:

sudo apt install libcgroup-dev make acl zip unzip pv mariadb-server apache2 \
      php php-fpm php-gd php-cli php-intl php-mbstring php-mysql \
      php-curl php-json php-xml php-zip composer ntp python3-yaml

The following command can be used on Fedora, and related distributions like Red Hat Enterprise Linux and Rocky Linux (before V9):

sudo dnf install libcgroup-devel make acl zip unzip pv mariadb-server httpd \
      php-gd php-cli php-intl php-mbstring php-mysqlnd php-fpm \
      php-xml php-zip composer chronyd python3-pyyaml

nginx can be used as an alternate web server.

The packages libcgroup-dev (libcgroup-devel on Fedora) and make are judgehost software requirements, but also needed here due to issue 862 <https://github.com/DOMjudge/domjudge/issues/862>.

Installation

These instructions assume a tarball, see this section for instructions to build from git sources.

The DOMjudge build/install system consists of a configure script and makefiles, but when installing it, some more care has to be taken than simply running ./configure && make && make install.

After installing the required software as described above, run configure. In this example to install DOMjudge in the directory domjudge under /opt:

./configure --prefix=/opt/domjudge
make domserver
sudo make install-domserver

Note that root privileges are required to set permissions and user and group ownership of password files and a few directories. If you run the installation targets as non-root, you will be shown how to perform these steps manually.

Database configuration

DOMjudge uses a MySQL or MariaDB database server for information storage. Where this document talks about MySQL, it can be understood to also apply to MariaDB.

Installation of the database is done with bin/dj_setup_database. For this, you need an installed and configured MySQL server and administrator access to it. Run:

dj_setup_database genpass
dj_setup_database [-u <mysql admin user>] [-p <password>|-r] install

This first creates the DOMjudge database credentials file etc/dbpasswords.secret if it does not exist already.

Then it creates the database and user and inserts some default/example data into the domjudge database. The option -r will prompt for a password for mysql; when no user is specified, the mysql client will try to read credentials from $HOME/.my.cnf as usual. The command uninstall can be passed to dj_setup_database to remove the DOMjudge database and users; this deletes all data!

The script also creates the initial “admin” user with password stored in etc/initial_admin_password.secret.

Web server configuration

For the web interface, you need to have a web server (e.g. nginx or Apache) installed on the DOMserver and made sure that PHP correctly works with it. Refer to the documentation of your web server and PHP for details. In the examples below, replace 8.2 with the PHP version you’re installing.

To configure the Apache web server for DOMjudge, use the Apache configuration snippet from etc/apache.conf. It contains examples for configuring the DOMjudge pages with an alias directive, or as a virtualhost, optionally with TLS; it also contains PHP and security settings. Reload the web server for changes to take effect.

ln -s <DOMSERVER_INSTALL_PATH>/etc/apache.conf /etc/apache2/conf-available/domjudge.conf
ln -s <DOMSERVER_INSTALL_PATH>/etc/domjudge-fpm.conf /etc/php/8.2/fpm/pool.d/domjudge.conf
a2enmod proxy_fcgi setenvif rewrite
a2enconf php8.2-fpm domjudge
# Edit the file /etc/apache2/conf-available/domjudge.conf and
# /etc/php/8.2/fpm/pool.d/domjudge.conf to your needs
service php8.2-fpm reload
service apache2 reload

An nginx webserver configuration snippet is also provided in etc/nginx-conf. You still need htpasswd from apache2-utils though. To use this configuration, perform the following steps:

ln -s <DOMSERVER_INSTALL_PATH>/etc/nginx-conf /etc/nginx/sites-enabled/domjudge
ln -s <DOMSERVER_INSTALL_PATH>/etc/domjudge-fpm.conf /etc/php/8.2/fpm/pool.d/domjudge.conf
# Edit the files /etc/nginx/sites-enabled/domjudge and
# /etc/php/8.2/fpm/pool.d/domjudge.conf to your needs
service php8.2-fpm reload
service nginx reload

On Fedora, use the following nginx configuration steps:

ln -s <DOMSERVER_INSTALL_PATH>/etc/nginx-conf /etc/nginx/conf.d/nginx-conf.conf
ln -s <DOMSERVER_INSTALL_PATH>/etc/domjudge-fpm.conf /etc/php-fpm.d/domjudge-fpm.conf
# Edit the files <DOMSERVER_INSTALL_PATH>/etc/nginx-conf and
# <DOMSERVER_INSTALL_PATH>/etc/domjudge-fpm.conf to your needs
systemctl restart php-fpm.service
systemctl restart nginx.service

The judgehosts connect to DOMjudge via the DOMjudge API so need to be able to access at least this part of the web interface.

Running behind a proxy or loadbalancer

When running the DOMserver behind a proxy or loadbalancer, you might still want to have the webserver and/or the DOMserver know the original client IP. By default DOMjudge and the webserver (both nginx and Apache) will not use the client IP, but rather the IP of the proxy / loadbalancer.

The preferred way to do this is in the webserver configuration. See /etc/apache2/conf-available/domjudge.conf for Apache and /etc/nginx/sites-enabled/domjudge for nginx. Look for loadbalancer in the file. When using this approach both the webserver and DOMjudge itself will know the actual IP of the client.

If you cannot edit the webserver configuration for some reason, there is an alternative way to configure this. Edit the file webapp/.env.local (create it if it does not exist) and add a line in the form of:

TRUSTED_PROXIES=1.2.3.4

Where 1.2.3.4 is the IP address of the proxy or loadbalancer. You can set multiple IP addresses by separating them by a comma (,). The drawback to this approach is that the webserver is not aware of the actual client IP. This means that access logs for the webserver will still report the IP of the proxy or loadbalancer.

Log in to DOMjudge

The DOMserver should now be operational. You can access the web application at your configured base URL. There’s an admin user with initial password found in etc/initial_admin_password.secret.

You can continue now with installing one or more judgehosts.