What is Docker?⌗

  • Docker is an open platform for developing, shipping and running applications.
  • Docker is a platform which packages an application and all its dependencies together in the form of containers.

What problem does Docker solve?⌗

The main problem it solves is dependency management. Image Description

Docker Architecture⌗

Image Description

Some Terms to Understand⌗

  1. Docker Daemon: Daemon is a program which runs on our computer and manages docker containers.
  2. Docker file: It is a text document which contains all the commands that a user can call on the command line to assemble an image.
  3. Images: Template to create docker container.
  4. Container: Running instance of docker image.Containers hold entire package to run application.

Basic Commands for Docker⌗

  • Check the version
docker -v
  • pull image
docker pull <image-name>
  • check all the images
docker images
  • search images
docker search <image-name>
  • container creation
docker run <image-name>
  • list all the running containers
docker ps
  • list all the running + stopped containers
docker ps -a
  • run container in background(detached mode) + change the name of container.
docker run --name <custom-name> -d <image-name/image-id>
  • run container in -it {interactive-mode}, your container will run continuously
docker run --name <custom-name> -it -d <image-id/name>
  • to execute the command inside your container
docker exec -it <container-id> command{python3/bash/java/cpp}
  • get all the information about the container
docker inspect <container-id>
  • stop the running container
docker stop <containerName>
  • remove image
docker rm <image-name>
  • to restart the running container
docker restart <container-id>

My-SQL Image Commands⌗

  • get the image
docker install mysql
  • run the mysql container
docker run --name <custome-mysql-name> -e MYSQL_ROOT_PASSWORD=<give-a-pass> -d mysql
  • use commands inside mysql container
docker exec -it <custom-sql-name> <command-type>

Docker for Touchstone MCQ Test⌗

1. Docker Basics⌗

  • What is Docker?
  • Benefits of using Docker
  • Docker vs Virtual Machines
  • Docker Architecture
    • Docker Engine
    • Docker Daemon
    • Docker Client

2. Docker Images⌗

  • What is a Docker Image?
  • Layers in Docker Images
  • Docker Hub and Image Registries
  • Pulling Images
    docker pull
  • Listing Images
    docker images
  • Removing Images
    docker rmi
  • Custom Images using Dockerfile
    (See Dockerfile section below)

3. Docker Containers⌗

  • What is a Container?
  • Creating Containers
    docker run
  • Listing Containers
    docker ps, docker ps -a
  • Starting/Stopping/Removing Containers
    docker start, docker stop, docker rm
  • Inspecting Containers
    docker inspect
  • Container Lifecycle
  • Running containers in detached mode
    -d
  • Executing commands inside containers
    docker exec, docker attach
  • Logs and Terminal access
    docker logs, docker exec -it

4. Dockerfile (Creating Custom Images)⌗

  • What is a Dockerfile?
  • Basic Dockerfile Instructions
    • FROM
    • RUN
    • COPY
    • ADD
    • CMD
    • ENTRYPOINT
    • EXPOSE
    • ENV
    • WORKDIR
  • Building Image from Dockerfile
    docker build
  • Best practices
    • Minimizing layers
    • Using .dockerignore

5. Docker Volumes (Data Persistence)⌗

  • What is a Volume?
  • Types
    • Volumes
    • Bind Mounts
  • Creating Volumes
    docker volume create
  • Mounting Volumes to Containers
    -v or --mount
  • Inspecting Volumes
    docker volume inspect
  • Volume Persistence and Sharing between Containers

6. Docker Networking⌗

  • Default Docker Networks
    • bridge
    • host
    • none
  • Creating Custom Networks
    docker network create
  • Connecting Containers to Networks
    --network
  • Inspecting Networks
    docker network inspect
  • Communication between containers
    Via network name

7. Docker Compose (Multi-container Applications)⌗

  • What is Docker Compose?
  • docker-compose.yml file structure
    • version
    • services
    • build
    • ports
    • volumes
    • depends_on
    • networks
  • Running with Compose
    docker-compose up, docker-compose down
  • Building and Rebuilding
    docker-compose build, docker-compose up --build
  • Scaling services
    docker-compose up --scale
  • Use cases and benefits

3 Ways To Create Docker Image⌗

Using spring-boot-maven-plugin to create docker image⌗

⚙️ Step 1: Build JAR⌗ 

mvn clean package

✅ Requirement⌗

  • spring-boot-maven-plugin in pom.xml

👉 Output:

  • Executable JAR → target/*.jar

📦 Step 2: Dockerfile⌗ 

FROM eclipse-temurin:21-jdk-alpine  
COPY target/*.jar app.jar  
ENTRYPOINT ["java","-jar","/app.jar"]

🧠 Key Concepts⌗

  • FROM → Base image
  • COPY → Add JAR into container
  • ENTRYPOINT → Run app

🏗️ Step 3: Build Image⌗ 

docker build -t myapp:v1 .

🔍 Breakdown⌗

  • -t → tag (name:version)
  • . → current directory (build context)