Deploying Dockerized Services

In this lesson, we will explore how to deploy Dockerized services effectively. Docker is a powerful tool for creating, deploying, and managing applications in containers. By the end of this lesson, you will understand the key concepts, prerequisite tools, and step-by-step processes required to deploy your services using Docker.

• Container: A lightweight, stand-alone, executable package of software that includes everything needed to run a piece of software.
• Image: A read-only template used to create containers. Images can be built from a Dockerfile.
• Dockerfile: A script containing a series of instructions on how to build a Docker image.
• Docker Hub: A cloud-based registry for sharing and managing Docker images.

Before deploying Dockerized services, ensure you have the following:

• Docker installed on your machine.
• A basic understanding of Docker concepts.
• Access to a cloud provider (optional, for production deployment).

4.1 Create a Dockerfile

A Dockerfile defines the environment for your application. Here's a simple example for a Node.js application:

FROM node:14
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 8080
CMD ["node", "app.js"]

4.2 Build the Docker Image

Run the following command in your terminal to build the Docker image:

docker build -t my-node-app .

4.3 Run the Docker Container

Once the image is built, you can run a container using the following command:

docker run -p 8080:8080 my-node-app

4.4 Push to Docker Hub

If you want to share your image, push it to Docker Hub:

docker login
docker tag my-node-app myusername/my-node-app
docker push myusername/my-node-app

• Keep your images small by using multi-stage builds.
• Use .dockerignore files to exclude files from the build context.
• Tag your images properly for version control.
• Regularly update your base images to apply security patches.