Master Docker Deployment: From Dockerfile to Running Containers

Docker is a containerization technology that packages applications and their dependencies into portable containers, greatly simplifying deployment.

Traditional deployment often suffers from environment differences (OS version, library mismatches), causing “works on dev machine, fails in production”. Docker solves this by bundling the runtime, libraries, and configuration into an image, ensuring consistency across development, testing, and production environments.

Docker containers share the host OS kernel, using fewer resources and starting in seconds compared to virtual machines.

Docker Deployment Process

The basic workflow: write a Dockerfile → build an image → run a container → access the service.

1. Write Dockerfile

FROM openjdk:17-slim
WORKDIR /app
COPY target/user-service.jar app.jar
EXPOSE 8081
ENTRYPOINT ["java","-jar","app.jar"]

2. Build Image

docker build -t user-service:1.0 .

You can build separate images for multiple microservices, e.g.:

docker build -t order-service:1.0 ./order
docker build -t product-service:1.0 ./product

3. Run Container

docker run -d -p 8081:8081 --name user user-service:1.0

Run additional containers for other services:

docker run -d -p 8082:8082 --name order order-service:1.0
docker run -d -p 8083:8083 --name product product-service:1.0

4. Access Service

http://localhost:8081/api/users
http://localhost:8082/api/orders

This process enables fast, standardized deployment of microservices, ensuring environment consistency and efficient management.