bitnami-containers/bitnami/tomcat

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.

TLDR

docker run --name tomcat bitnami/tomcat

Docker Compose

tomcat:
  image: bitnami/tomcat

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.

git clone https://github.com/bitnami/bitnami-docker-tomcat.git
cd bitnami-docker-tomcat
docker build -t bitnami/tomcat .

Deploying web applications on Tomcat

This Tomcat image exposes a volume at /app. This path acts as the Tomcat webapps 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 at startup.

Note! You can also deploy web applications on a running Tomcat instance.

docker run -v /path/to/app:/app bitnami/tomcat

or using Docker Compose:

tomcat:
  image: bitnami/tomcat
  volumes:
    - /path/to/app:/app

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

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

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

Configuration

Setting the manager password on first run

By default, the manager user is not assigned a password. To secure your Tomcat server you should assign a password to this user. Passing the TOMCAT_PASSWORD environment variable when running the image for the first time will set the password of the manager user to the value of TOMCAT_PASSWORD.

docker run --name tomcat -e TOMCAT_PASSWORD=password123 bitnami/tomcat

or using Docker Compose:

tomcat:
  image: bitnami/tomcat
  environment:
    - TOMCAT_PASSWORD=password123

Configuration files

This image looks for Tomcat configuration files in /bitnami/tomcat/conf. You can mount a volume at this location with your own configuration, or the default configuration will be copied to your volume if it is 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/conf:/bitnami/tomcat/conf bitnami/tomcat

or using Docker Compose:

tomcat:
  image: bitnami/tomcat
  volumes:
    - /path/to/tomcat/conf:/bitnami/tomcat/conf

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

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

Further Reading:

• Tomcat 7 Configuration Reference

Logging

The Bitnami Tomcat Docker Image supports two different logging modes: logging to stdout, and logging to a file.

Logging to stdout

The default behavior is to log to stdout, as Docker expects. These will be collected by Docker, converted to JSON and stored in the host, to be accessible via the docker logs command.

docker logs tomcat

or using Docker Compose:

docker-compose logs tomcat

This method of logging has the downside of not being easy to manage. Without an easy way to rotate logs, they could grow exponentially and take up large amounts of disk space on your host.

Logging to file

To log to file, run the Tomcat image, mounting a directory from your host at /bitnami/tomcat/logs. This will instruct the container to send logs to your directory.

docker run --name tomcat -v /path/to/tomcat/logs:/bitnami/tomcat/logs bitnami/tomcat

or using Docker Compose:

tomcat:
  image: bitnami/tomcat
  volumes:
    - /path/to/tomcat/logs:/bitnami/tomcat/logs

To perform operations (e.g. logrotate) on the logs, mount the same directory in a container designed to operate on log files, such as logstash.

Maintenance

Backing up your container

To backup your configuration and logs, follow these simple steps:

Step 1: Stop the currently running container

docker stop tomcat

or using Docker Compose:

docker-compose stop tomcat

Step 2: Run the backup command

We need to mount two volumes in a container we will use to create the backup: a directory on your host to store the backup in, and the volumes from the container we just stopped so we can access the data.

docker run --rm -v /path/to/backups:/backups --volumes-from tomcat busybox \
  cp -a /bitnami/tomcat /backups/latest

or using Docker Compose:

docker run --rm -v /path/to/backups:/backups --volumes-from `docker-compose ps -q tomcat` busybox \
  cp -a /bitnami/tomcat /backups/latest

Note! If you only need to backup configuration, you can change the first argument to cp to /bitnami/tomcat/conf.

Restoring a backup

Restoring a backup is as simple as mounting the backup as volumes in the container.

docker run -v /path/to/backups/latest/conf:/bitnami/tomcat/conf \
  -v /path/to/backups/latest/logs:/bitnami/tomcat/logs \
  bitnami/tomcat

or using Docker Compose:

tomcat:
  image: bitnami/tomcat
  volumes:
    - /path/to/backups/latest/conf:/bitnami/tomcat/conf
    - /path/to/backups/latest/logs:/bitnami/tomcat/logs

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

Before continuing, you should backup your container's configuration and logs.

Follow the steps on creating a backup.

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, restoring your backup if necessary.

docker run --name tomcat bitnami/tomcat:latest

or using Docker Compose:

docker-compose start tomcat

Testing

This image is tested for expected runtime behavior, using the Bats testing framework. You can run the tests on your machine using the bats command.

bats test.sh

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_APP_VERSION inside the container)
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

License

Copyright 2015 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.