The basic concepts and steps to get you started with Docker:

Category : Docker | Sub Category : Docker for Java Developers | By Prasad Bonam Last updated: 2023-08-03 14:20:57 Viewed : 325

Docker is a popular platform used to develop, deploy, and run applications in containers. Containers are lightweight, portable, and isolated environments that allow developers to package their applications with all the dependencies required to run consistently across different environments. In this Docker tutorial, I will cover the basic concepts and steps to get you started with Docker:

1. Installation: First, you need to install Docker on your machine. Visit the official Docker website and download the appropriate version for your operating system (Windows, macOS, or Linux).

2. Docker Concepts: Before diving into commands, familiarize yourself with some fundamental Docker concepts:

• Images: Images are read-only templates that define the application, along with its code, runtime, libraries, and other dependencies.

• Containers: Containers are running instances of images. Each container is an isolated environment that runs your application.

• Dockerfile: A Dockerfile is a text file that contains instructions to build a Docker image.

3. Building and Running Your First Container: Create a simple web application, and save it in a directory along with a Dockerfile. Here is a basic example of a Dockerfile:

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# Use an existing base image (e.g., Node.js)
FROM node:14

# Set the working directory inside the container
WORKDIR /app

# Copy the application files into the container
COPY package.json package-lock.json ./
COPY app.js ./

# Install dependencies
RUN npm install

# Expose the port that the application listens on
EXPOSE 3000

# Command to run the application
CMD ["node", "app.js"]

Save the Dockerfile in the same directory as your web application files.

4. Build the Docker Image: Open a terminal (or command prompt) in the directory containing the Dockerfile and run the following command to build the Docker image:

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docker build -t my-app .

The -t option tags the image with a name, in this case, my-app.

5. Run the Container: After successfully building the image, you can run a container based on it using the following command:

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docker run -p 3000:3000 my-app

The -p option maps port 3000 from the container to port 3000 on your host machine, allowing you to access the web application from http://localhost:3000.

6. Manage Docker Containers: To list all running containers, use:

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docker ps

To stop a container, use:

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docker stop CONTAINER_ID

To remove a container, use:

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docker rm CONTAINER_ID

7. Pushing to Docker Hub (Optional): If you want to share your Docker image with others, you can push it to Docker Hub. First, create an account on Docker Hub (https://hub.docker.com/). Then, tag your image with your Docker Hub username and the repository name:

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docker tag my-app username/my-app

Finally, push the image to Docker Hub:

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docker push username/my-app

This is a basic introduction to using Docker. As you explore further, you will discover more features and capabilities of Docker, such as using Docker Compose for multi-container applications, Docker volumes for persistent data, and Docker Swarm for orchestrating container clusters. The Docker documentation is an excellent resource for learning more about Dockers advanced features and best practices.