Prerequisites for Installing XNAT

XNAT is built to run within a Tomcat webserver and uses a PostgreSQL database to store data. To install XNAT, you will need to first install its prerequisites (Java, PostgreSQL, and Tomcat). After successfully installing the prerequisites, you can download the XNAT site builder  which will build an XNAT web application and deploy it to Tomcat. If you are experienced with XNAT, you can also download developmental versions of XNAT using the Build XNAT from Source Repository instructions.

These applications should be installed and tested prior to installing XNAT:

  • Java JDK v1.7:  ( Download)
    • Unix Users: The Oracle JDK is recommended.  We've seen issues with the applets when using OpenJDK and the IcedTea plugin.
    • Function: Runs core XNAT engine.
    • Make sure to install the JDK and not the JRE.

      Oracle very much wants you to download Java 8. Java 8 is acceptable for clients, i.e. if you're running XNAT applets in your browser. XNAT 1.6.4 does not work with Java 8! Make sure you download the latest version of the Java 7 JDK. We are working on migrating XNAT to work with Java 8, but there's no timetable for delivery.

  • PostgreSQL v9.3 ( Download ( Installation Guide)
    • Function: Database backend 
    • XNAT 1.6 supports v9.1+, but you should use the latest available version.
  • Apache Tomcat v7  ( Download) (Installation Guide)
    • Function: Web application server
    • You will need to set the size of the heap and perm gen space available to the JVM running your Tomcat instance. See the page on  Configuring Tomcat  for more information.
    • Windows users:
        • I f you run Tomcat as a service, confirm that the java version is set to a JDK (not just a JRE).
        • Installing Tomcat in Program Files or Program Files (x86) is NOT recommended; UAC can cause problems for Tomcat here.  An alternate location such as C:\Servers\Tomcat would be best.

      As of the 1.6.5 release, XNAT is not compatible with Apache Tomcat 8. Please make sure that you download the latest version of Tomcat 7, but there are a number of known issues with XNAT running on Tomcat 8.