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Updating Containers with Watchtower

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, the team has decided that they need a way to manage container updates. After doing some research, the team has discovered Watchtower. Watchtower is a container that updates all running containers when changes are made to the image that it is running. You have been tasked with creating a proof of concept for the team. You will need to create a Dockerfile that will be used to create a Docker image. The image will be pushed to Docker Hub. Next, you will create a container using this image. Once the image is created, you will deploy the Watchtower container. After Watchtower is deployed, you will update the Dockerfile, rebuild the image, and push the changes to Docker Hub. Watchtower checks for changes every 30 seconds. Once it detects the changes, Watchtower will update the running container. For more information on Watchtower you can go [here](

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Path Info

Clock icon Intermediate
Clock icon 1h 0m
Clock icon Nov 07, 2018

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Table of Contents

  1. Challenge

    Create the Dockerfile

    Create a Dockerfile:

    vi Dockerfile

    The Dockerfile should contain the following:

    FROM node
    RUN mkdir -p /var/node
    ADD content-express-demo-app/ /var/node/
    WORKDIR /var/node
    RUN npm install
    CMD ./bin/www
  2. Challenge

    Build the Docker Image

    Build the Docker image:

    docker build -t USERNAME/express -f Dockerfile .
  3. Challenge

    Push the Image to Docker Hub

    Login to Docker Hub:

    docker login

    Push the image to Docker Hub:

    docker push USERNAME/express
  4. Challenge

    Create a Demo Container

    Create the container that Watchtower will monitor:

     docker run -d --name demo-app -p 80:3000 --restart always USERNAME/express
  5. Challenge

    Create the Watchtower Container

    Create the Watchtower container that will monitor the demo-app container:

    docker run -d --name watchtower --restart always -v /var/run/docker.sock:/var/run/docker.sock containrrr/watchtower -i 30
  6. Challenge

    Update the Docker Image

    Update the Docker image:

    docker build -t USERNAME/express -f Dockerfile .

    Repush the image to Docker Hub:

    docker push USERNAME/express:latest

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