- Lab
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Using Watchtower to Keep Containers Up to Date
Tired of having to manually update several containers, you’ve decided to look for an automated solution. After doing some research, you have discovered Watchtower. Watchtower is a container that updates all running containers when changes are made to the image that it is running. 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](https://github.com/v2tec/watchtower).
Path Info
Table of Contents
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Challenge
Create the Dockerfile
Create a Dockerfile:
[cloud_user@host]$ vi DockerfileThe Dockerfile should contain the following:
FROM node RUN mkdir -p /var/node ADD src/ /var/node/ WORKDIR /var/node RUN npm install EXPOSE 3000 CMD ./bin/www -
Challenge
Build the Docker Image
Build the Docker image:
[cloud_user@host]$ docker image build -t USERNAME/lab-watchtower -f Dockerfile . -
Challenge
Push the Image to Docker Hub
Login to Docker Hub:
docker loginPush the image to Docker Hub:
docker image push USERNAME/lab-watchtower -
Challenge
Create a Demo Container
Create the container that Watchtower will monitor:
[cloud_user@host]$ docker container run -d --name demo-app -p 80:3000 --restart always USERNAME/lab-watchtower -
Challenge
Create the Watchtower Container
Create the Watchtower container that will monitor the
demo-appcontainer:[cloud_user@host]$ docker run -d --name watchtower --restart always -v /var/run/docker.sock:/var/run/docker.sock v2tec/watchtower -i 30 -
Challenge
Update the Docker Image
After creating /var/node, add an instruction to create /var/test.
Update the Docker image:
[cloud_user@host]$ vi DockerfileAdd change to Dockerfile:
RUN mkdir -p /var/testRebuild the image:
[cloud_user@host]$ docker build -t USERNAME/lab-watchtower -f Dockerfile .Push the new image:
[cloud_user@host]$ docker image push USERNAME/lab-watchtower
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