Docker – Tomcat with Docker

We have been seeing multiple articles on how to run applications inside the Docker container. Similarly in this article we will see how we can run a tomcat server in a Docker container. We will also expose ports so that we can access the tomcat application.

Search for the Docker container with tomcat server by using the command “docker search tomcat” which will give the details below,

Now once we got the tomcat image to be downloaded and used, we can then write the DockerFile to this purpose.

Create a DockerFile with the below contents

[root@vx111a testTomcat]# cat Dockerfile
FROM tomcat
MAINTAINER tomcat/ub jagadish
COPY ./myApp.war /usr/local/tomcat/webapps/
CMD ["catalina.sh","start"]

As we can see that we are going to use the “tomcat” image for our purpose. In the second line we have the MAINTAINER details. The third line will copy the application myApp.war from the current location to the /usr/local/tomcat/webapps/ location inside the container. The last step is to run the command cataline.sh by passing the argument Start to that.

Lets build the docker using the DockerFile created as,

[root@vx111a testTomcat]# docker build -t jagadish/tomcat .
Sending build context to Docker daemon 4.096 kB
Step 0 : FROM tomcat
Trying to pull repository docker.io/library/tomcat ... latest: Pulling from library/tomcat
6d1ae97ee388: Pull complete
8b9a99209d5c: Pull complete
2e05a52ffd47: Pull complete
9fdaeae348bb: Pull complete
67d05086af43: Pull complete
2e9d1ec89d66: Pull complete
1afb0d51eee0: Pull complete
5cb24a57fa37: Pull complete
110c2f290b04: Pull complete
966dcd51a14f: Pull complete
8a57ce404f1b: Pull complete
e1b97b980d07: Pull complete
548f21c48132: Pull complete
3e93be06ad38: Pull complete
3e2882dd7e87: Pull complete
4ef5a14c7b39: Pull complete
fca011d2612a: Pull complete
119ddf0db1a7: Pull complete
1b8329afb263: Pull complete
Digest: sha256:6880839ca278600ea2a853455dd73c8ec8db9c0860d4aafc4a2b8b4d23dcdd85
Status: Downloaded newer image for docker.io/tomcat:latest
 ---> 1b8329afb263
Step 1 : MAINTAINER tomcat/ub jagadish
 ---> Running in e0588ccfdb59
 ---> c5829c11b42b
Removing intermediate container e0588ccfdb59
Step 2 : COPY ./myApp.war /usr/local/tomcat/webapps/
 ---> b3765f3df7c3
Removing intermediate container 091028d853b9
Step 3 : CMD catalina.sh start
 ---> Running in 0aba2a5f35a4
 ---> ca997a0f848e
Removing intermediate container 0aba2a5f35a4
Successfully built ca997a0f848e

Now once the Tomcat Image for docker is downloaded and configured, we can see the image using the “docker images” as,

[root@vx111a testTomcat]# docker images
REPOSITORY          TAG               IMAGE ID          CREATED           VIRTUAL SIZE
jagadish/tomcat      latest            ca997a0f848e     6 minutes ago    350 MB

Now once we have the Tomcat Container downloaded and available, we can run the Docker container using the above iamge as,

[root@vx111a testTomcat]# docker run -t -t -p 8080:8080 jagadish/tomcat /usr/local/tomcat/bin/catalina.sh run

Using CATALINA_BASE:   /usr/local/tomcat
Using CATALINA_HOME:   /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
****************
08-Jan-2016 13:51:26.925 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"]
08-Jan-2016 13:51:26.925 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 547 ms

We ran the Cataline.sh command by passing the “run” argument to it. Once we ran the command we will also see the catalina.sh logs shown on the screen.

We also made sure that the ports 8080 is exposed on the tomcat docker container that we are running. Now we can access the tomcat container using the http://localhost:8080 which will show you the tomcat container login page.