Docker Basic Example

Example: Run python app

Alternative: Dockerizing a Jupyter Notebook (with repo2docker)

Basic process:

1. Create Dockerfile

2. Run

   docker build .

   which creates an image based on the Dockerfile in . with context ..

   Alternative: With Docker file (-f) flag:

   docker build -f /path/to/a/Dockerfile .

In Detail:

1. Create Dockerfile, e.g here an example Dockerfile:

   Dockerfile

   # our base image (a linux distribution)
   FROM alpine:latest
   
   # Install python and pip
   RUN apk add --update py-pip
   
   # install Python modules needed by the Python app
   COPY requirements.txt /usr/src/app/
   RUN pip install --no-cache-dir -r /usr/src/app/requirements.txt
   
   # copy files required for the app to run
   COPY app.py /usr/src/app/
   COPY templates/index.html /usr/src/app/templates/
   
   # tell the port number the container should expose
   EXPOSE 5000
   
   # run the application
   CMD ["python", "/usr/src/app/app.py"]

   WORKDIR sets the directory from which all following commands will be exectued by default.

2. Build (with tag flag (-t) to create a name for your image with a tag of the form name:tag)

   docker build -t andrusch/myfirstapp .

3. Run

   docker run -p 8888:5000 --name myfirstapp andrusch/myfirstapp

Here in 8888:5000, 8888 stands for the external port you can use outside of the docker container (e.g. in your browser or via Insomnia/Postman) and 5000 for the internal port which is open in the container.

4. Visit http://192.168.99.100:8888/, 192.168.99.100 was found using $ docker-machine ip docker-default.

5. Stop and remove container when done

   $ docker stop myfirstapp
   $ docker rm myfirstapp

Example: Run apache container

To run a basic php app with apache:

1. Create a simple Dockerfile which pulls the tutum/apache-php image

   Dockerfile

   FROM tutum/apache-php
   RUN rm -fr /app
   ADD . /app

2. Build

   docker build -t my-name/my-app .

3. Run

   docker run -p 4545:80 my-name/my-app

Example: Run nginx server

1. Create Dockerfile

   Dockerfile

   FROM alpine:3.16.0
   
   RUN apk update
   RUN apk add nginx
   
   ENTRYPOINT ["nginx", "-g", "daemon off;"]

2. Build image

   docker build -t my-nginx .

3. Run container: Creates and runs the container

   docker run -it -p 8081:80 --name super-duper2 my-nginx

4. Go to http://localhost:8081 on you system.

   If you see the following it was a success: