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Docker Compose for DevOps Engineers

Docker Compose for DevOps Engineers

Day 18 of 90daysofdevops

Abhisek Moharana's photo
Abhisek Moharana
·

3 min read

Table of contents

Docker Compose

  • Docker Compose is a tool provided by Docker that allows you to define and manage multi-container Docker applications. It simplifies the process of running and orchestrating multiple Docker containers as a cohesive application.

  • With Docker Compose, you can define the services, networks, volumes, and other configurations for your application in a single YAML file called a "docker-compose.yml" file. This file serves as a blueprint for your application's architecture and allows you to specify the relationships and dependencies between the containers.

YAML in Docker

  • YAML (YAML Ain't Markup Language) refers to a popular data serialization format that is human-readable and commonly used for configuration files, data exchange, and storing structured data.

  • In Docker, YAML (YAML Ain't Markup Language) is a human-readable data serialization format used for configuring and defining Docker Compose files. Docker Compose is a tool that allows you to define and manage multi-container Docker applications.

Task 1: Running Multiple Containers using Docker Compose

  1. Get the repository

     mkdir proj2
 cd proj2
 git clone https://github.com/Abhisek773/node-todo-cicd.git
 cd node-todo-cicd

  2. Install docker-compose

     sudo apt-get install docker-compose -y

  3. Create docker-compose.yaml file and configure all the details

     vim docker-compose.yaml

 #file contains
 version: '3.9'

 services:
   web:
     image: abhisek6/node_todo_app:latest
     ports:
       - "8000:8000"

  4. To start the container we use docker-compose up

     docker-compose up -d

  5. Now the application is up & running.

  6. To bring down the application we use docker-compose.

     docker-compose down

Task 2: Docker Commands

  1. Pull a pre-existing Docker image from a public repository (e.g. Docker Hub) and run it on your local machine. Run the container as a non-root user (Hint- Use usermod command to give the user permission to docker). Make sure you reboot the instance after permitting the user.

     docker pull abhisek6/react_django_app:latest

  2. Inspect the container's running processes and exposed ports using the docker inspect command.

     docker inspect <container_id>

  3. Use the docker logs command to view the container's log output.

     docker log <container_id>

  4. Use the docker stop and docker start commands to stop and start the container.

     docker stop <container_id>
 docker start <container_id>

  5. Use the docker rm command to remove the container when you're done.

     # Before removing container it should be stopped first
 docker rm <container_id>

Thank You,

I want to express my deepest gratitude to each and every one of you who has taken the time to read, engage, and support my journey as a becoming DevOps Engineer.

Feel free to reach out to me if any corrections or add-ons are required on blogs. Your feedback is always welcome & appreciated.

~ Abhisek Moharana 😊

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