Adding Metadata and Labels

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Adding Metadata and Labels

For the last six months, the Acme Anvil Corporation has been migrating some of their bare-metal infrastructure to Docker containers. After the initial implementation, you mention to the team that labels can be used for storing metadata about images and containers. This is useful for keeping track of image and container attributes like the build date and application version. Your team thinks this is a great idea, and you’ve been tasked with creating a quick demo to show how useful labels can be. You created a small weather app a few months ago while learning Node.js, and it’s perfect for a quick demo. On your Docker workstation, you will create a Dockerfile that contains four labels: the maintainer, build date, application name, and application version. You will then build the image and push it to Docker Hub. On your Docker server, you will create a new container using the `weather-app` image. Once the container is running, you will update the branch of your application, rebuild the image, and push the changes to Docker Hub. On the Docker server, Watchtower will update the running container with the new version of the image.

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Lab Info

Level

Intermediate

Last updated

May 18, 2025

Duration

1h 0m

Challenge

Create a Dockerfile

Create a Dockerfile using the following instructions:

FROM node

LABEL maintainer="EMAIL_ADDRESS"

ARG BUILD_VERSION
ARG BUILD_DATE
ARG APPLICATION_NAME

LABEL org.label-schema.build-date=$BUILD_DATE
LABEL org.label-schema.application=$APPLICATION_NAME
LABEL org.label-schema.version=$BUILD_VERSION

RUN mkdir -p /var/node
ADD weather-app/ /var/node/
WORKDIR /var/node
RUN npm install
EXPOSE 3000
CMD ./bin/www

Challenge

Build the Docker Image

Build the Docker image using the following parameters:

docker build -t <USERNAME>/weather-app --build-arg BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') 
--build-arg APPLICATION_NAME=weather-app --build-arg BUILD_VERSION=v1.0  -f Dockerfile .

Challenge

Push the Image to Docker Hub
Push the weather-app image to Docker Hub.
```
docker push <USERNAME>/weather-app
```

Challenge

Create the `weather-app` Container

Start the weather-app container.

docker run -d --name demo-app -p 80:3000 --restart always <USERNAME>/weather-app

Challenge

Check Out Version v1.1 of the Weather App
In the weather-app directory, check out version v1.1 of the weather app.
```
cd weather-app
git checkout v1.1
cd ../ 
```

Challenge

Rebuild the `weather-app` Image

Rebuild and push the weather-app image.

docker build -t <USERNAME>/weather-app --build-arg BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') /
--build-arg APPLICATION_NAME=weather-app --build-arg BUILD_VERSION=v1.1  -f Dockerfile .

docker push <USERNAME>/weather-app

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