What is Tomcat?

Apache Tomcat, often referred to as Tomcat, is an open-source web server and servlet container developed by the Apache Software Foundation (ASF). Tomcat implements several Java EE specifications including Java Servlet, JavaServer Pages (JSP), Java EL, and WebSocket, and provides a "pure Java" HTTP web server environment for Java code to run in.

TL;DR;

$ docker run --name tomcat bitnami/tomcat:latest

Docker Compose

$ curl -sSL https://raw.githubusercontent.com/bitnami/bitnami-docker-tomcat/master/docker-compose.yml > docker-compose.yml
$ docker-compose up -d

Kubernetes

WARNING: This is a beta configuration, currently unsupported.

Get the raw URL pointing to the kubernetes.yml manifest and use kubectl to create the resources on your Kubernetes cluster like so:

$ kubectl create -f https://raw.githubusercontent.com/bitnami/bitnami-docker-tomcat/master/kubernetes.yml

Why use Bitnami Images?

• Bitnami closely tracks upstream source changes and promptly publishes new versions of this image using our automated systems.
• With Bitnami images the latest bug fixes and features are available as soon as possible.
• Bitnami containers, virtual machines and cloud images use the same components and configuration approach - making it easy to switch between formats based on your project needs.
• Bitnami images are built on CircleCI and automatically pushed to the Docker Hub.
• All our images are based on minideb a minimalist Debian based container image which gives you a small base container image and the familiarity of a leading linux distribution.

Supported tags and respective Dockerfile links

• 9.0, 9.0.0-M22-r0 (9.0/Dockerfile)
• 8.5, 8.5.16-r0 (8.5/Dockerfile)
• 8.0, 8.0.45-r0, latest (8.0/Dockerfile)
• 7, 7.0.79-r0 (7/Dockerfile)

Subscribe to project updates by watching the bitnami/tomcat GitHub repo.

Get this image

The recommended way to get the Bitnami Tomcat Docker Image is to pull the prebuilt image from the Docker Hub Registry.

$ docker pull bitnami/tomcat:latest

To use a specific version, you can pull a versioned tag. You can view the list of available versions in the Docker Hub Registry.

$ docker pull bitnami/tomcat:[TAG]

If you wish, you can also build the image yourself.

$ docker build -t bitnami/tomcat:latest https://github.com/bitnami/bitnami-docker-tomcat.git

Persisting your application

If you remove the container all your data and configurations will be lost, and the next time you run the image the database will be reinitialized. To avoid this loss of data, you should mount a volume that will persist even after the container is removed.

For persistence you should mount a directory at the /bitnami path. If the mounted directory is empty, it will be initialized on the first run.

$ docker run -v /path/to/tomcat-persistence:/bitnami bitnami/tomcat:latest

or using Docker Compose:

version: '2'

services:
  tomcat:
    image: 'bitnami/tomcat:latest'
    ports:
      - '8080:8080'
    volumes:
      - /path/to/tomcat-persistence:/bitnami

Deploying web applications on Tomcat

The /bitnami/tomcat/data directory is configured as the Tomcat webapps deployment directory. At this location, you either copy a so-called exploded web application, i.e. non-compressed, or a compressed web application resource (.WAR) file and it will automatically be deployed by Tomcat.

Additionally a helper symlink /app is present that points to the webapps deployment directory which enables us to deploy applications on a running Tomcat instance by simply doing:

$ docker cp /path/to/app.war tomcat:/app

Note! You can also deploy web applications on a running Tomcat instance using the Tomcat management interface.

Further Reading:

• Tomcat Web Application Deployment

Accessing your Tomcat server from the host

To access your web server from your host machine you can ask Docker to map a random port on your host to port 8080 exposed in the container.

$ docker run --name tomcat -P bitnami/tomcat:latest

Run docker port to determine the random ports Docker assigned.

$ docker port tomcat
8080/tcp -> 0.0.0.0:32768

You can also manually specify the ports you want forwarded from your host to the container.

$ docker run -p 8080:8080 bitnami/tomcat:latest

Access your web server in the browser by navigating to http://localhost:8080.

Configuration

Environment variables

The Tomcat instance can be customized by specifying environment variables on the first run. The following environment values are provided to custom Tomcat:

• TOMCAT_SHUTDOWN_PORT_NUMBER: Tomcat shutdown port. Default: 8005
• TOMCAT_HTTP_PORT_NUMBER: Tomcat HTTP port. Default: 8080
• TOMCAT_AJP_PORT_NUMBER: Tomcat AJP port. Default: 8009
• JAVA_HOME: Java home directory.
• JAVA_OPTS: Tomcat java settings. Default: -Djava.awt.headless=true -XX:+UseG1GC -Dfile.encoding=UTF-8
• TOMCAT_HOME: Tomcat user's home directory. Default: /home/tomcat
• TOMCAT_USERNAME: Tomcat user. Default: user
• TOMCAT_PASSWORD: Tomcat password.
• TOMCAT_ALLOW_REMOTE_MANAGEMENT: Allow to connect to manager applications from remote addresses. Valid values are 0 and 1. Default: 0

Creating a custom user

By default, a management user named user is created and is not assigned a password. Passing the TOMCAT_PASSWORD environment variable when running the image for the first time will set the password of this user to the value of TOMCAT_PASSWORD.

Additionally you can specify a user name for the management user using the TOMCAT_USERNAME environment variable. When not specified, the TOMCAT_PASSWORD configuration is applied on the default user (user).

Specifying Environment variables using Docker Compose

version: '2'

services:
  tomcat:
    image: 'bitnami/tomcat:latest'
    ports:
      - '8080:8080'
    environment:
      - TOMCAT_USERNAME=my_user
      - TOMCAT_PASSWORD=my_password

Specifying Environment variables on the Docker command line

$ docker run --name tomcat \
  -e TOMCAT_USERNAME=my_user \
  -e TOMCAT_PASSWORD=my_password \
  bitnami/tomcat:latest

Configuration files

The image looks for configurations in /bitnami/tomcat/conf/. As mentioned in Persisting your application you can mount a volume at /bitnami and copy/edit the configurations in the /path/to/tomcat-persistence/tomcat/conf/. The default configurations will be populated to the conf/ directory if it's empty.

Step 1: Run the Tomcat image

Run the Tomcat image, mounting a directory from your host.

$ docker run --name tomcat -v /path/to/tomcat-persistence:/bitnami bitnami/tomcat:latest

or using Docker Compose:

version: '2'

services:
  tomcat:
    image: 'bitnami/tomcat:latest'
    ports:
      - '8080:8080'
    volumes:
      - /path/to/tomcat-persistence:/bitnami

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

eg.

$ vim /path/to/tomcat-persistence/tomcat/conf/server.xml

Step 3: Restart Tomcat

After changing the configuration, restart your Tomcat container for the changes to take effect.

$ docker restart tomcat

or using Docker Compose:

$ docker-compose restart tomcat

Refer to the Tomcat configuration manual for the complete list of configuration options.

Logging

The Bitnami Tomcat Docker image sends the container logs to the stdout. To view the logs:

$ docker logs tomcat

or using Docker Compose:

$ docker-compose logs tomcat

You can configure the containers logging driver using the --log-driver option if you wish to consume the container logs differently. In the default configuration docker uses the json-file driver.

Maintenance

Upgrade this image

Bitnami provides up-to-date versions of Tomcat, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.

Step 1: Get the updated image

$ docker pull bitnami/tomcat:latest

or if you're using Docker Compose, update the value of the image property to bitnami/tomcat:latest.

Step 2: Stop and backup the currently running container

Stop the currently running container using the command

$ docker stop tomcat

or using Docker Compose:

$ docker-compose stop tomcat

Next, take a snapshot of the persistent volume /path/to/tomcat-persistence using:

$ rsync -a /path/to/tomcat-persistence /path/to/tomcat-persistence.bkp.$(date +%Y%m%d-%H.%M.%S)

Step 3: Remove the currently running container

$ docker rm -v tomcat

or using Docker Compose:

$ docker-compose rm -v tomcat

Step 4: Run the new image

Re-create your container from the new image.

$ docker run --name tomcat bitnami/tomcat:latest

or using Docker Compose:

$ docker-compose start tomcat

Notable Changes

8.0.35-r3

• TOMCAT_USER parameter has been renamed to TOMCAT_USERNAME.

8.0.35-r0

• All volumes have been merged at /bitnami/tomcat. Now you only need to mount a single volume at /bitnami/tomcat for persistence.
• The logs are always sent to the stdout and are no longer collected in the volume.

Contributing

We'd love for you to contribute to this container. You can request new features by creating an issue, or submit a pull request with your contribution.

Issues

If you encountered a problem running this container, you can file an issue. For us to provide better support, be sure to include the following information in your issue:

• Host OS and version
• Docker version (docker version)
• Output of docker info
• Version of this container (echo $BITNAMI_IMAGE_VERSION inside the container)
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

Community

Most real time communication happens in the #containers channel at bitnami-oss.slack.com; you can sign up at slack.oss.bitnami.com.

Discussions are archived at bitnami-oss.slackarchive.io.

License

Copyright (c) 2015-2017 Bitnami

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.