Docker Image Deployment

docker-image-deployment

Summary

Deploy a containerized scientific application (MetFrag webapp) by pulling a Docker image, mapping network ports, configuring runtime environment variables, and verifying HTTP accessibility at the exposed endpoint. This skill bridges container orchestration with application deployment validation.

When to use

When you have a containerized scientific tool available on Docker Hub (e.g., ipbhalle/metfragweb) and need to make it accessible on a host at a specified HTTP endpoint, or when you need to customize JVM memory, web application paths, or configuration files at container runtime without rebuilding the image.

When NOT to use

• The containerized application requires persistent data storage across container restarts and you have not set up a named volume or bind mount for the application state.
• You need to run multiple instances with coordinated networking or service discovery; use Docker Compose or Kubernetes instead of single docker run commands.
• The host system does not have Docker installed or you lack permission to run privileged Docker commands.

Inputs

• Docker image name and tag (string, e.g., 'ipbhalle/metfragweb')
• Host port number (integer)
• Container internal port number (integer, typically 8080 for Tomcat)
• Optional: JVM memory configuration string (e.g., '-Xmx4g -Xms4g')
• Optional: WEBPREFIX string (e.g., 'mymetfrag')
• Optional: settings.properties file (path on host filesystem)

Outputs

• Running Docker container instance accessible at HOST:HOST_PORT
• HTTP endpoint responding with application homepage (HTTP 200)
• Container startup logs documenting Tomcat initialization
• Deployed MetFrag webapp accessible via web browser or HTTP client

How to apply

Pull the Docker image from the registry (e.g., docker pull ipbhalle/metfragweb). Run the container using docker run with port mapping (-p HOST_PORT:CONTAINER_PORT, typically -p 8888:8080 for Tomcat). Set environment variables (JAVA_OPTS for JVM memory heap sizes, WEBPREFIX for the webapp path, or settings.properties file location) as needed. Mount configuration files via -v HOST_PATH:/resources/settings.properties if using custom settings. Allow time for the embedded Tomcat application server to initialize. Verify successful deployment by making a GET request to the exposed HTTP endpoint (e.g., http://localhost:8888/MetFragWeb) and confirming a 200 response or valid webpage content is returned.

Related tools

• Docker (Container runtime and orchestration—pulls, runs, and manages the containerized MetFrag webapp with port mapping and environment variable configuration.)
• Tomcat (Embedded Java web application server inside the container—listens on internal port 8080 and serves the MetFrag webapp after initialization.)
• Java 21 (Runtime environment required by MetFrag; JVM memory heap sizes are configured via JAVA_OPTS environment variable.)
• MetFrag (Scientific application packaged in the Docker image; provides mass spectrometry analysis web interface.) — https://github.com/ipb-halle/MetFragRelaunched

Examples

docker run -it --rm -e JAVA_OPTS="-Xmx4g -Xms4g" -e WEBPREFIX=mymetfrag -v $(pwd)/settings.properties:/resources/settings.properties -p 8888:8080 ipbhalle/metfragweb

Evaluation signals

• HTTP GET request to http://localhost:HOST_PORT/WEBPREFIX returns HTTP status 200 and valid HTML content.
• Container logs show successful Tomcat startup messages with no ERROR or FATAL level entries during initialization.
• Port mapping is active: docker ps shows the container with PORTS column displaying 0.0.0.0:HOST_PORT->8080/tcp.
• Custom environment variables are applied: if JAVA_OPTS is set, the JVM process inside the container reports the configured heap sizes via jps -v or container logs.
• Configuration file is mounted correctly: if settings.properties is provided via -v, the running container's /resources/settings.properties is readable and contains expected configuration parameters (e.g., ChemSpiderToken, proxy settings).

Limitations

• The container requires the Docker daemon to be running and accessible; deployment will fail on systems without Docker or with permission restrictions.
• JVM memory limits (JAVA_OPTS) must be less than the host system's total available memory; misconfiguration causes out-of-memory container termination.
• Port 8080 inside the container is hardcoded; if you need the webapp on a different internal port, you must rebuild the image or use a reverse proxy.
• Configuration via settings.properties is not validated at container startup; invalid proxy or database credentials will only be detected when those services are first queried at runtime.
• No automatic health checks or restart policies are configured by default; the container will exit if Tomcat crashes, and manual intervention is required to restart.

Evidence

• [readme] This container packages the MetFrag (https://github.com/ipb-halle/MetFragRelaunched) webapp and some text databases based on the latest official tomcat docker container.: "This container packages the MetFrag (https://github.com/ipb-halle/MetFragRelaunched) webapp and some text databases based on the latest official tomcat docker container."
• [readme] Run MetFrag at http://localhost:8888/MetFragWeb docker run -it --rm -p 8888:8080 ipbhalle/metfragweb: "docker run -it --rm -p 8888:8080 ipbhalle/metfragweb"
• [readme] environment variable JAVA_OPTS="-Xmx?g -Xms?g" to adjust jvm memory: "environment variable JAVA_OPTS="-Xmx?g -Xms?g" to adjust jvm memory"
• [readme] Run Metfrag at http://localhost:8888/mymetfrag with 4GB JVM size using a settings file from ./settings.properties docker run -it --rm -e JAVA_OPTS="-Xmx4g -Xms4g" -e WEBPREFIX=mymetfrag -v $(pwd)/settings.properties:/resources/settings.properties -p 8888:8080 ipbhalle/metfragweb: "docker run -it --rm -e JAVA_OPTS="-Xmx4g -Xms4g" -e WEBPREFIX=mymetfrag -v $(pwd)/settings.properties:/resources/settings.properties -p 8888:8080 ipbhalle/metfragweb"
• [other] The MetFrag webapp is deployed by running the ipbhalle/metfragweb Docker container with port mapping (-p 8888:8080) to expose the internal Tomcat port 8080 to the host port 8888, making the application accessible at the specified HTTP endpoint.: "The MetFrag webapp is deployed by running the ipbhalle/metfragweb Docker container with port mapping (-p 8888:8080) to expose the internal Tomcat port 8080 to the host port 8888"
• [readme] automatic use of a metfrag settings file if provided at /resources/settings.properties: "automatic use of a metfrag settings file if provided at /resources/settings.properties"