Creates a vanilla Tomcat 7 Docker container running under OpenJDK 7. Tomcat 7 is installed from the Ubuntu LTS repository so there are no external downloads. CATALINA_BASE is set to /tomcat, which is created via Ubuntu's tomcat7-instance-create utility. The process runs under an unprivileged user/group called tcuser (uid/gid 9000). We use that rather than the tomcat7 user created by Ubuntu's Tomcat package in order to help decouple child images from the version number and to deny the user write access to directories outside of $CATALINA_BASE.
Port 8080 is exposed for HTTP.
The following volumes are defined, since typically you don't want child images to inherit these:
- /tomcat/logs
- /tomcat/work
- /tomcat/temp
Place your web apps under /tomcat/webapps. There are none installed by default.