Running a sample.war file in a Tomcat Docker container is straightforward with the right configuration. Here’s a step-by-step guide:

1. Prepare Your Project

Ensure you have the following ready:

• A sample.war file (your Java web application archive - for example Tomcat doc sample).
• A Dockerfile to configure the Docker container.

2. Dockerfile Configuration

Create a Dockerfile in the same directory as your sample.war file with the following content:

FROM tomcat:11.0.2

ADD sample.war /usr/local/tomcat/webapps/

EXPOSE 8080
CMD ["catalina.sh", "run"]

Explanation:

• FROM tomcat:11.0.2 Uses the official Tomcat 11.0.2 image as the base.
• ADD sample.war /usr/local/tomcat/webapps/ Adds the sample.war file to the Tomcat webapps directory for deployment.
• EXPOSE 8080 Exposes port 8080 for accessing the application.
• CMD [“catalina.sh”, “run”] Starts Tomcat in the foreground.

3. Build the Docker Image

Run the following command to build the Docker image:

docker build -t tomcat-sample .

Here:

• -t tomcat-sample specifies the name of the image.

4. Run the Docker Container

Start the container using:

docker run -d -p 8080:8080 --name tomcat-sample-container tomcat-sample

Explanation:

• -d Runs the container in detached mode.
• -p 8080:8080 Maps port 8080 of the container to port 8080 on the host.
• –name tomcat-sample-container Assigns a name to the container.
• tomcat-sample Specifies the image to use.

5. Access the Application

Once the container is running, access your application in a web browser at: http://localhost:8080/sample

Replace localhost with the appropriate IP address if running on a remote server.

6. Verify the Deployment

You should see your application’s homepage or a Tomcat message confirming successful deployment.