All About Docker and Docker compose

docker
docker-compose
Into to Docker and Docker compose
Author

ujjal

Published

May 4, 2025

What is Docker?

Docker is platform, where we can developing, shipping and running application.

A Docker Container is standalone, lightweight and executable package that contain everything needed to run an application.

How Docker Works?

  1. First we create Dockerfile
FROM python:3.8-slim

COPY requirements.txt .

RUN pip install -r requirements.txt

COPY . /opt/ml/code/
COPY src/serve /usr/local/bin/serve

# Set permissions for the serve script
RUN chmod +x /usr/local/bin/serve

# Set the working directory
WORKDIR /opt/ml/code

# Expose the port FastAPI will run on
EXPOSE 8080

# Start the FastAPI server using the serve script
ENTRYPOINT ["/usr/local/bin/serve"]

  1. build a container image using docker buildx build -t myapp:latest . command. Here . (dot) means current directory.

  2. Run docker container

    docker run myapp

  3. push docker image to docker hub or AWS ECR(Elastic Container Registry). Here i will push docker image into AWS ECR.

    1. First authenticate docker client with aws erc registry.aws ecr get-login-password --region us-east-2 | docker login --username AWS --password-stdin <account-id>[.dkr.ecr.us-east-2.amazonaws.com](http://590183925485.dkr.ecr.us-east-1.amazonaws.com/)
    2. tag image - docker tag myapp:latest <account-id>[.dkr.ecr.us-east-2.amazonaws.com/myapp:latest](http://590183925485.dkr.ecr.us-east-1.amazonaws.com/resume-segmentation-model:latest)
    3. push image - docker push <account-id>[.dkr.ecr.us-east-2.amazonaws.com/myapp:latest](http://590183925485.dkr.ecr.us-east-1.amazonaws.com/resume-segmentation-model:latest)

Here one question came to your mind why docker image push to container registry

Docker Command that I used frequently

Docker Basic

# list of docker image
docker images

# list of running images
docker ps

# list of all image, including staus(last exited time)
docker ps -a

# build a image (Here .(dot) means currnt directory). here -t is tag. it assign name and version
docker buildx build -t myapp:latest .

# run docker image
docker run myapp:latest

# attatch shell
docker exec -it 5974bbd6498d bash

Docker Run Command

syntax of docker run command

        `docker run [OPTIONS] IMAGE [COMMAND] [ARG...]`
  • OPTIONSflag configure setting of container
  • IMAGE is name of docker image
  • COMMAND is run command when container is started
  • ARG - Argument pass to command

Here Some most frequently options

  • -d, --detach run container in background
  • -i, -it, --interactive run container in interactive mode(Allocate interactive terminal)
  • --name assign name to container
  • -p, --publish <host_port>:<container_port>
docker run -d --name my-ml-webapp -p 8080:80 -e ENV=production myapp:latest

What is Docker Compose?

Docker compose is a tools is used for define and managed multi-container application. It use docker-compose.yaml file to describe the service, network and volume

we use docker compose where multiple services(like frontend, backend, database) running i n same machine. In one of my project i use docker compose, where using docker compose i mange redis, postgres, Fastapi backend server, and react frontend server.

Main application of docker compose is such application where multiple container dependent with other. Like backend server dependent on redis and postgres container. By using docker compose up command we start entire application, instead of running all container on by one.

sample docker-compose.yaml file -

version: "1.0.0"

services:
  redis:
    image: redis:7
    ports:
      - "6379:6379"

  postgres:
    image: postgres:15
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydb
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/var/lib/postgresql/data

  backend:
    build:
      context: ./backend
    container_name: fastapi-backend-server
    depends_on:
      - postgres
      - redis
    ports:
      - "8000:8000"
    environment:
      - ENV=dev

  frontend:
    build:
      context: ./frontend
    container_name: frontend
    ports:
      - "80:80"
    depends_on:
      - backend

volumes:
  pgdata:

Some Docker Compose command

# start all services define docker-compose.yaml file
docker compose up
# stop and remove container, volumn and network
docker compose down
# restart all service
docker compose restart
# stop all service
docker compose stop
# build image and start services
docker compose up --build

References