• How many images are available on this host?

sudo docker images

Image

  • What is the size of the ubuntu image?

sudo docker images

Image

  • We just pulled a new image. What is the tag on the newly pulled NGINX image?

Image

  • We just downloaded the code of an application. What is the base image used in the Dockerfile? Inspect the Dockerfile in the webapp-color directory.

  • ls
  • cd webapp-color
  • ls
  • cat Dockerfile

Image

  • To what location within the container is the application code copied to during a Docker build? Inspect the Dockerfile in the webapp-color directory.

  • ls
  • cd webapp-color
  • ls
  • cat Dockerfile

Image

  • When a container is created using the image built with this Dockerfile, what is the command used to RUN the application inside it.

  • ls
  • cd webapp-color
  • ls
  • cat Dockerfile

Image

  • What port is the web application run within the container?

  • ls
  • cd webapp-color
  • ls
  • cat Dockerfile

Image

  • Build a docker image using the Dockerfile and name it webapp-color. No tag to be specified.
ls 
webapp-color
cd webapp-color/
ls   
Dockerfile  app.py  requirements.txt  templates
sudo docker build . -t webapp-color

Image

  • Run an instance of the image webapp-color and publish port 8080 on the container to 8282 on the host.

sudo docker run -p 8282:8080 webapp-color

Image

  • Access the application by clicking on the tab named HOST:8282 above your terminal.

Image

  • What is the base Operating System used by the python:3.6 image? If required, run an instance of the image to figure it out.

sudo docker run -d python:3.6 cat /etc/*release

Image

  • What is the approximate size of the webapp-color image?

sudo docker images

Image

  • That’s really BIG for a Docker Image. Docker images are supposed to be small and light weight. Let us try to trim it down.

  • Build a new smaller docker image by modifying the same Dockerfile and name it webapp-color and tag it lite. Find a smaller base image for python:3.6. Make sure the final image is less than 150MB.Modify Dockerfile to use python:3.6-alpine image and then build using docker build -t webapp-color:lite .

Dockerfile :

FROM python:3.6-alpine
RUN pip install flask
COPY . /opt/
EXPOSE 8080
WORKDIR /opt
ENTRYPOINT ["python", "app.py"]

sudo docker built . -t webapp-color:lite

Image

  • Run an instance of the new image webapp-color:lite and publish port 8080 on the container to 8383 on the host.

sudo docker run -d -p 8383:8080 webapp-color:lite

Image