Deploying application as Docker Container

Docker

Docker is a platform that packages an application and all its dependencies together in the form of a container. The containerization aspect ensures that the application works in any environment.

How to deploy an application with docker

1. Create an EC2 instance in the AWS console.

   

2. Check if the docker services are installed on the system
   systemctl status docker

   

3. Now, install docker by using the below command
   sudo apt-get install docker

   

   systemctl status docker

   

4. Adding current user and docker to a group to avoid adding sudo every time to run docker commands
   sudo usermod -aG docker $USER

   

5. Pull a git repo that you want to deploy with docker.
   git clone https://github.com/LondheShubham153/react_django_demo_app

   

6. Now go inside react_django_demo_app
   and list the contents to know the requirements to run the application

   

   .py files indicate that it requires Python, and Django is also used to run the app.

   Now, we need to write a Dockerfile to build the image which in turn is used to run the container.
   vi Dockerfile

   

   Syntax of Dockerfile

   Environment Variable	Function
   FROM	A FROM statement defines which image to download and start from. Example: To download the Python image from the docker hub. FROM python:3.9
   COPY	Copy files from the local system from source to destination Example: Copy all the files from the current directory and pasting in the same docker. COPY . .
   RUN	The RUN statement defines running a command through the shell, waiting for it to finish and saving the result. Example: To install the requirement.txt via PIP RUN pip install -r requirements.txt
   CMD	CMD specifies the whole command to run. Example: To run the Django development server from anywhere on port 8000 CMD ["python","manage.py","runserver","0.0.0.0:8000"]

7. Now you need to build an image from Dockerfile by the following command
   docker build . -t react-django-app:latest

   Note: . ---> dot refers to the Dockerfile location which is current directory
   -t ---> it is for tagging the image

   

8. Now the final step is to run the container.
   To run the container you need to give the below command:
   docker run -d -p 8000:8000 react-django-app:latest

   

9. Now in your EC2 instance edit the inbound rules in the security group for port 8000

   

10. Now you can run the application with the help of the public IP address of your instance at port 8000

    

    Woo Hoo!!!
    It's done.
    You have finally deployed an application with the help of Docker.

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