Docker Compose Port Mapping

Docker is an essential tool that simplifies the deployment process by encapsulating applications within a container. To facilitate various types of communication in a Docker container, we need to expose port. Here in this guide, I will first cover what is Docker and Docker Compose and how Docker has become an essential tool among developers. Then I will guide you through the steps to do port mapping in a Docker compose YAML file.

What is Docker?

Docker is an important tool that is used to encapsulate the application and its dependencies into compact units called Docker containers. The Docker container contains all the application code, runtime, libraries, and other tools that an application needs to run. Here for the application, first a Dockerfile is created. The Dockerfile consists of a base image, commands to install dependencies, and commands to run the application. This Dockerfile is then built to generate a Docker image. The Docker image is very lightweight and portable. By using this Docker image, we can run a Docker container on any operating system with the only condition is the system should have installed Docker on it. This allows developers to run their application code on their operating system without facing any errors related to the operating system or hardware requirements. Developers can run multiple Docker containers on a single host. This results in maximizing resource utilization and reducing infrastructure costs. In summary, we can say Docker has become a very important and essential tool for developers and organizations to accelerate their software deployment and delivery pipelines.

What Is Docker Compose?

Docker Compose is an important tool for managing multi-docker container applications. Here all the configurations, services, dependencies, and environment variables of the application are defined in a single YAML file. In this YAML file, multiple docker container configuration details are written. With a single command, users can start all the docker containers that are mentioned in the Docker Compose YAML file. Docker Compose allows users to easily deploy, scale, and manage the docker containers. This saves time and effort in the development process. It increases productivity and efficiency. As the deployment process becomes more easy, users can now easily focus more on developing application logic. Overall Docker Compose simplifies complex workflows and accelerates development cycles making it a vital tool in the modern software development and deployment process.

Pre-requisites

Before moving on to the next section, make sure that you have installed Docker and Docker Compose on your system. If you have not installed Docker and Docker Compose, then follow these detailed geeks for geeks articles to install Docker and Docker Compose on your system.

• For Windows users: Docker – Installation on Windows
• For Ubuntu users: How To Install and Configure Docker in Ubuntu?
• Docker Compose Installation guide: Installation of Docker Compose

Steps To Do Port Mapping In A Docker Compose YAML File

Step 1 : Create a Docker Compose YAML file .

version: '3.1'
services:
  webserver:
    image: nginx
    ports:
      - 80:80

Step 2 : Then run the docker compose file using the command below .

docker compose up -d

Here the flag '-d' is used to run the container in the detached mode .

Step 3 : Now connect localhost:80 from your browser you will see you can connect the nginx web page .

Step 4 : You can also map multiple ports to port 80 and also can connect from the port from the browser . Look this updated Docker Compose file where i have mentioned multiple ports .

version: '3.1'
services:
  webserver:
    image: nginx
    ports:
      - 80:80
      - 8080:80
      - 8091:80

Step 5 : Now again run the docker compose command .

docker compose up -d

Step 6 : Connect the ports 80,8080 and 8091 from the browser to see the nginx server .

Through port 80 :

Through port 8080 :

Through port 8091 :

Conclusion

Here in this article you have first understand what is Docker . Then you have understand about Docker Compose . After this you have created a Docker Compose file by using a Nginx image and also you have exposed the port in the Docker Compose so that you can connect the Nginx from the browser at the port 80 .