🐳 Docker Guide

📋 Table of Contents

• Dockerfile
• Docker Commands
• Persistent Data and Volume Management
• Connecting Containers
• Docker Networking
• Pro Tips
• Important Links

🏗️ Dockerfile

FROM node
WORKDIR /myapp
COPY . /myapp/
RUN npm install
EXPOSE 3000
CMD ["npm", "start"]

🛠️ Docker Commands

Create a Docker Image

docker build -t .

Check Docker Images

docker images

OR

docker images ls

Run the Image Inside a Container

docker run

Check Running Containers

docker ps

Bind Container Port to Host Port

docker run -p 3000:3000

Run Docker Image in the Background

docker run -d -p 3000:3000

Run Multiple Containers from One Image

docker run -d -p 3001:3000 docker run -d -p 3002:3000 docker run -d -p 3004:3000

View All Containers (Running and Stopped)

docker ps -a

Delete a Container

docker rm

Stop a Running Container

docker stop

Automatically Delete Container After Stopping

docker run -d --rm -p 3000:3000

Name Containers and Images

Assign a Name to a Container

docker run -d --rm --name "prabin" -p 3001:3000

Tagging Images

docker build -t prabin:01 . docker build -t prabin:02 .

Predefined Images

Use a Specific Node.js Version in Dockerfile

FROM node:latest # Or specify a version: node:14

Pull Other Images

docker pull python docker pull nginx

Run an NGINX Container

docker run -p 8000:80 nginx:latest

Access via: http://localhost:8000

💾 Persistent Data and Volume Management

Save Data with Volumes

docker run -it --rm -v myvolume:/myapp

• -v indicates volume usage.
• myvolume is the volume name.
• /myapp is the working directory in the Docker container.

Check Volumes

docker volume ls

Inspect Volume Details

docker volume inspect myvolume

Mounting Local Files to Container

Mount a File

docker run -it -v /path/to/local/file:/container/path -rm

Example:

docker run -it -v /User/root/Documents/pythonfilecontainer/requirement.txt:/myapp/requirement.txt -rm

🔗 Connecting Containers

Connecting Two Containers (e.g., Python and MySQL)

Run a MySQL Container

docker pull mysql:latest docker run -d --name mysqldb -e MYSQL_ROOT_PASSWORD="root" -e MYSQL_DATABASE="userinfo" mysql

Inspect MySQL Container for IP Address

docker inspect mysqldb

Use the IP address (e.g., 172.17.0.2) to connect in your Python code:

host = "172.17.0.2" user = "root" password = "root" database = "userinfo"

Local MySQL and Python Code in Containers

Use host.docker.internal as the MySQL host:

host = "host.docker.internal" user = "root" password = "root" database = "userinfo"

🌐 Docker Networking

Create a Docker Network

docker network create my-net

Run a MySQL Container on the Network

docker run -d --env MYSQL_DATABASE="userinfo" --env MYSQL_ROOT_PASSWORD="root" --name mysqldb --network my-net mysql

Update Python Code to Use MySQL Container Name as Host

host = "mysqldb" user = "root" password = "root" database = "userinfo"

💡 Pro Tips

• Always use specific versions for base images in production Dockerfiles.
• Use multi-stage builds to keep your final image size small.
• Leverage Docker Compose for managing multi-container applications.
• Regularly prune unused Docker objects to save disk space.

🔗 Important Links

• Docker Documentation
• Docker Hub
• Docker Compose Documentation
• Best practices for writing Dockerfiles

Happy Dockerizing! 🐳✨

These commands enhance your Docker workflow with:

• Image versioning and portability
• Container debugging
• System maintenance
• Resource management
• Network configuration
• Volume handling
• Service orchestration
• Monitoring capabilities

Each command is production-ready and commonly used in real-world scenarios.