Building a Docker Image and Running a Container

This is a simple guide on how to build a Docker image from your project and run a container from that image.

Step 1: Install Docker

Make sure Docker is installed on your system.

Commands:

sudo apt update
sudo apt install docker.io -y
sudo systemctl start docker
sudo systemctl enable docker
docker --version

Step 2: Create a Project Directory

Commands:

mkdir myapp
cd myapp

Create your application files here (like app.py, index.html, etc.).

Step 3: Create a Dockerfile

Create a file named Dockerfile inside your project folder. Here’s an example for a Python app:

FROM python:3.9-slim
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
EXPOSE 5000
CMD ["python", "app.py"]

Step 4: Build the Docker Image

Command:

docker build -t myapp:latest .

• -t myapp:latest → name and tag for the image
• . → current directory as context

Check if the image is created:

docker images

Step 5: Run a Container from the Image

Command:

docker run -d -p 5000:5000 --name mycontainer myapp:latest

• -d → run in background
• -p 5000:5000 → map port 5000 from container to local
• --name mycontainer → name of the container

Check running containers:

docker ps

Step 6: Manage Containers and Images

Commands:

docker stop mycontainer
docker start mycontainer
docker rm mycontainer
docker rmi myapp:latest