devops-exercises/exercises/devops/solutions/containerize_app.md

Containerize an Application

1. Clone an open source project you would like to containerize. A couple of suggestions:

https://github.com/bregman-arie/node-hello-world
https://github.com/bregman-arie/flask-hello-world

git clone https://github.com/bregman-arie/node-hello-world

2. Write a Dockerfile you'll use for building an image of the application (you can use any base image you would like)

FROM alpine
LABEL maintainer="your name/email"
RUN apk add --update nodejs npm
COPY . /src
WORKDIR /src
RUN npm install
EXPOSE 3000
ENTRYPOINT ["node", "./app.js"]

3. Build an image using the Dockerfile you've just wrote

docker image build -t web_app:latest .

4. Verify the image exists

docker image ls

5. [Optional] Push the image you've just built to a registry

docker login
docker image tag web_app:latest <your username>/web_app:latest
# Verify with "docker image ls"
docker image push <your username>/web_app:latest

6. Run the application

docker container run -d -p 80:3000 web_app:latest

7. Verify the app is running

docker container ls
docker logs <container ID/name>
# In the browser, go to 127.0.0.1:80