🐳Two-Tier Application Deployment with Docker

🌌First Let's go through the overview.

I've been working on deploying a 2-tier Flask application using Docker. First, I containerized the application and then pushed the image to Docker Hub. For the database, I decided to go with MySQL. To simplify the management of the containers and ensure they're on the same network, I used Docker Compose. This setup has made deploying and managing the application's components much easier. With Docker Compose, I could define all the services, networks, and volumes in a single file, streamlining the deployment process. Pushing the Docker image to Docker Hub also means that I can deploy the application on any machine with Docker installed with ease. MySQL provides a reliable and scalable data storage solution for my application. Overall, leveraging Docker's containerization technology and Docker Compose's orchestration capabilities has allowed me to create a robust and scalable deployment environment for my Flask application.

🌌Let's understand which Tools & Technology we need to make this application

👨‍💻EC2

Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides resizable compute capacity in the cloud.

👨‍💻GitHub

It is a web-based platform used for version control and collaboration on software development projects.

Here are some key features of GitHub:

1. Version Control: GitHub uses Git, a distributed version control system, to track changes to files and manage different versions of a project. Developers can create branches to work on new features or fixes and merge them back into the main branch when ready.

2. Collaboration: GitHub facilitates collaboration among team members by allowing them to review and discuss code changes, suggest improvements, and track issues and bugs using the built-in issue tracking system.

3. Code Hosting: GitHub provides a place to host code repositories, making it easy for developers to share their code with others and contribute to open-source projects.

4. Integration: GitHub integrates with a wide range of development tools and services, such as continuous integration (CI) systems, project management tools, and code editors, to streamline the development workflow.

5. Community: GitHub has a large and active community of developers, making it a valuable resource for learning, sharing knowledge, and finding solutions to coding problems.

Overall, GitHub is a powerful platform that helps developers collaborate on projects, manage code changes, and build software more efficiently.

👨‍💻Docker

It is a platform and tool that allows you to develop, deploy, and run applications inside containers.

👨‍💻Dockerfile

A Dockerfile is a text document that contains a set of instructions for building a Docker image.

👨‍💻Docker Image

A Docker image is a lightweight, standalone, executable package that contains everything needed to run a piece of software, including the code, runtime, libraries, dependencies, and configuration files.

👨‍💻Docker-compose

Docker Compose is a tool provided by Docker that allows you to define and run multi-container Docker applications. It uses a YAML file (docker-compose.yml) to configure the services, networks, and volumes for your application, making it easy to manage complex Docker environments.

👨‍💻Docker Hub

Docker Hub is a cloud-based registry service provided by Docker that allows you to store and share Docker images.

👨‍💻Docker Volume

In Docker, a volume is a way to persist data generated by and used by Docker containers. Volumes are stored outside the container's filesystem.

Here are some key points about Docker volumes:

Persistent Storage: Volumes provide a way to store data generated by containers persistently.

Shared Data: Volumes can be shared between containers.

Mount Points: Volumes are mounted into containers as directories.

1. Types of Volumes: Docker supports several types of volumes, including host-mounted volumes, named volumes, and anonymous volumes. Each type has its own use cases and benefits.

2. Managing Volumes: Volumes can be managed using the Docker CLI or through Docker Compose. You can create, inspect, remove, and manage volumes using these tools.

Overall, Docker volumes provide a flexible and convenient way to manage persistent data in Docker containers, making it easier to build and deploy applications that require persistent storage.

👨‍💻MYSQL

MySQL is an open-source relational database management system (RDBMS) that is widely used for building scalable, high-performance web applications. It is known for its reliability, easE of use. it uses Structured Query Language (SQL)

Some key features of MySQL include:

1. Relational Database: MySQL is a relational database, which means that it stores data in tables with rows and columns.

2. Scalability: MySQL is designed to scale from small, single-user applications to large, multi-user applications.

3. Ease of Use: MySQL is known for its ease of use, with a simple installation process and a user-friendly interface for managing databases.

4. Compatibility: MySQL is compatible with many operating systems and programming languages, making it easy to integrate with existing systems and applications.

🌌Now, Here we go through the 2-Tier Application Deployment with Docker

We will see how to troubleshoot while making the 2-Tier App.

✔️Login to AWS Console.

✔️Search EC2 & Click on Launch Instances.

✔️Fill the form 1) Name of Instance 2) Select Ubuntu Image 3) Instance Type- t2.micro 4) Create New Key-Pair 5) Launch Instance.

✔️Connect the Instance-> You'll get Ubuntu Terminal.

✔️Update the System & Install Docker.

sudo apt-get update # Update the System
sudp apt-get install docker.io # Install Docker

✔️Changes the Ownership of the Docker socket file to the current user.

sudo chown $USER /var/run/docker.sock

✔️To Check the List of the Container.

docker ps   # Check list of container

✔️Then Go to GitHub, Clone the Repository.

✔️Check the Repository clone or not.

ls  # listing the directory.

✔️Change the Directory.

cd two-tier-flask-app/    # Your Clone Directory Name

✔️Make Dockerfile.

# Use an official Python runtime as the base image
FROM python:3.9-slim

# Set the working directory in the container
WORKDIR /app

# install required packages for system
RUN apt-get update \
    && apt-get upgrade -y \
    && apt-get install -y gcc default-libmysqlclient-dev pkg-config \
    && rm -rf /var/lib/apt/lists/*

# Copy the requirements file into the container
COPY requirements.txt .

# Install app dependencies
RUN pip install mysqlclient
RUN pip install --no-cache-dir -r requirements.txt

# Copy the rest of the application code
COPY . .

# Specify the command to run your application
CMD ["python", "app.py"]

✔️Now, Build Dockerfile.

docker build . -t flaskapp

✔️Check the Image of flaskapp

docker images  # To check the images

✔️Now, go to your EC2 instance security group open port no. 5000 & save it.

✔️Now run the container of flaskapp

docker run -d -p 5000:5000 flaskapp:latest

✔️Then for collecting data of flaskapp Mysql connect through local server

docker run -d -p 3306:3306 --name mysql -e MYSQL_ROOT_PASSWORD="admin" mysql:5.7

✔️To check containers running or not

docker ps

✔️Now both containers are running on different Network so, create network to add both container in 1 network.

docker network create twotier # Two tier is network name(you can change network name)

✔️Now, kill the both containers that are not in same network.

docker kill <containerID> # you can kill muiltiple containers, you just add container_ID one by one

✔️Check, Now Images will get empty.

docker images

✔️Then, once again to attach both containers in same network.

docker run -d -p 5000:5000 --network=twotier -e MYSQL_HOST=mysql -e MYSQL_USER=admin -e MYSQL_PASSWORD=admin -e MYSQL_DB=myDb flaskapp:latest  #to attach in same network
docker run -d -p 3306:3306 --network=twotier -e MYSQL_DATABASE=myDb -e MYSQL_USER=admin -e MYSQL_PASSWORD=admin -e MYSQL_ROOT_PASSWORD=admin mysql:5.7 #to attach in same network

✔️Check, whether both containers are in same network or not

docker network ls

✔️To Inspect twotier network but, Still it shows container name different.

docker network inspect twotier

✔️So, Once again kill the both containers

docker kill <containerID>

✔️Run the both container again

docker run -d -p 5000:5000 --network=twotier -e MYSQL_HOST=mysql -e MYSQL_USER=admin -e MYSQL_PASSWORD=admin -e MYSQL_DB=myDb --name=flaskapp flaskapp:latest # run again container
docker run -d -p 3306:3306 --network=twotier -e MYSQL_DATABASE=myDb -e MYSQL_USER=admin -e MYSQL_PASSWORD=admin -e MYSQL_ROOT_PASSWORD=admin --name=mysql mysql:5.7 # run the container if not work then remove old mysql container and run again mysql container

✔️Now, to go into Mysql database

docker exec -it <containerID> bash   # your containerID will be different

✔️Enter the Password to enter into the database

mysql -u root -p   # when you press the enter then give password to them. You can enter mysql database

✔️To check all datases in MYSQL.

show databases;

✔️To use particular database.

use myDb;   # myDb is particular database name

✔️Now in myDb database Create Table Messages & run it.

CREATE TABLE messages (id INT AUTO_INCREMENT PRIMARY KEY, message TEXT);  #syntax of create a table in database

✔️Now access your flaskapp using your EC2 public-ip:5000 & write something.

✔️You can check your data will get save in table.

select * from messages;   # to check all data of the table

✔️To exit from database.

exit

✔️If you want to save your flaskapp image in Dockerhub, login to dockerhub.

docker login # Give username & password of your dockerhub

#Once login succeeded

✔️Now tag your image to username of docker with image name

docker tag  flaskapp:latest dockerwithalmas/flaskapp:latest

✔️You can see image with your username

COPY

docker images

✔️Let's try to push image on dockerhub.

COPY

docker push dockerwithalmas /flaskapp:latest

✔️Check with your dockerhub.

✔️If you want to run both containers in one command - flaskapp, mysql.

Install docker-compose.

sudo apt-get install docker-compose -y

✔️Make docker-compose.yml file.

version: '3'
services:

  backend:
    build:
      context: .
    ports:
      - "5000:5000"
    environment:
      MYSQL_HOST: mysql
      MYSQL_USER: admin
      MYSQL_PASSWORD: admin
      MYSQL_DB: myDb
    depends_on:
      - mysql

  mysql:
    image: mysql:5.7
    ports:
      - "3306:3306"
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: myDb
      MYSQL_USER: admin
      MYSQL_PASSWORD: admin
    volumes:
      - ./message.sql:/docker-entrypoint-initdb.d/message.sql   # Mount sql script into container's /docker-entrypoint-initdb.d directory to get table automatically created
      - mysql-data:/var/lib/mysql  # Mount the volume for MySQL data storage

volumes:
  mysql-data:

✔️check docker container

docker ps

✔️Once again Kill & Remove both containers

docker kill <containerID> # kill both containers
docker rm <containerID> # remove both containers

✔️Now run docker-compose command. It will create network automatically.

docker-compose up -d  # it creates network automatically.
docker-compose down   # it down the access

✔️Finally, access your flask app -> publicip:5000

🎊This FlaskApp access under the one network..

I believe this blog will be really helpful, giving you fresh perspectives and teaching you something new and interesting. 🙏

😊 Enjoy learning!