Please note that these documents apply to OpenShift Online v2 only (accounts created before August 1st, 2016).
If you are using one of the OpenShift 3 products, please refer to documents available at

Tomcat Application Hosting

OpenShift Online currently supports Tomcat 6 and 7 via JBoss EWS cartridges.

Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies. It powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations.

Learn more at the Tomcat homepage.

Powered by Tomcat

The Tomcat (JBossEWS) Cartridge

The jbossews cartridge provides Tomcat on OpenShift via the JBoss EWS package. This cartridge has special functionality to enable integration with OpenShift and with other cartridges. See Cartridge Integrations (below) and Environment Variable Replacement Support for details.

Cartridge Integrations

The jbossews cart has out-of-the-box integration support with the RedHat postgresql and mysql cartridges. The default context.xml contains two basic JDBC Resource definitions, jdbc/MySQLDS and jdbc/PostgreSQLDS, which will be automatically configured to work with their respective cartridges if installed into your application.