This is a simple docker image file that gives you a repeatable Java/Tomcat container running in a CentOS environment. Laying down your application or any specific configuration details are beyond the scope of this example.
You'll obviously need a working version of Docker to follow this example. You can follow the documentation to get it setup or, if you're on an Ubuntu 12.04 machine (my test box), you can simply:
curl -s https://get.docker.io/ubuntu/ | sudo sh
$ git clone https://github.com/danielkennedy/docker-tomcat.git
$ cd docker-tomcat
$ wget http://download.oracle.com/otn-pub/java/jdk/7u55-b13/jdk-7u55-linux-x64.tar.gz
$ wget https://www.apache.org/dist/tomcat/tomcat-7/v7.0.53/bin/apache-tomcat-7.0.53.tar.gz
$ sudo docker build -t docker-tomcat .
$ sudo docker run -d -p 8080:8080 docker-tomcat
$ sudo docker ps
Of course, the quickest way to verify that Tomcat is listening and the port is exposed is to simply point a browser to localhost on port 8080. Beyond that, you can:
$ sudo netstat -antp | grep 8080
tcp6 0 0 :::8080 :::* LISTEN 629/docker
$ wget localhost:8080
--2014-04-17 12:53:51-- http://localhost:8080/
Resolving localhost (localhost)... 127.0.0.1
Connecting to localhost (localhost)|127.0.0.1|:8080... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: `index.html'
[ <=> ] 11,197 --.-K/s in 0s
2014-04-17 12:53:51 (137 MB/s) - `index.html' saved [11197]
Now you need to deployyour web application. Chef? More Docker? Your choice.