Learn how to work with Docker containers

Learn how to work with Docker containers

Working with Docker containers involves creating, managing, and deploying containers for applications.

Here’s a step-by-step guide on how to work with Docker containers.

1. Installing Docker on Your System

Steps

• On Windows:

  Download and install Docker Desktop from Docker's website.

• On macOS:

  Download and install Docker Desktop from Docker's website.

• On Linux (Ubuntu):

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  sudo apt update
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  sudo apt install docker.io
  

2. Basic Docker Commands

2.1 Running a Docker Container

To run a simple container, use the following command:

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docker run <image-name>

Example:

Running a simple Ubuntu container

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docker run ubuntu

2.2 Building a Docker Image

To build a Docker image from a Dockerfile, use:

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docker build -t my-image-name:tag .

Example:

Building an image from a Dockerfile

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docker build -t my-app:latest .

3. Managing Containers

3.1 Listing Running Containers

1. To see running containers:

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docker ps

2. To list all containers (running and stopped):

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docker ps -a

3.2 Stopping and Removing Containers

1. Stop a container:

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docker stop <container-id>

2. Remove a stopped container:

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docker rm <container-id>

3.3 Executing Commands Inside a Container

1. To execute a command inside a running container:

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docker exec -it <container-id> <command>

Example:

2. Running a shell inside a container

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docker exec -it my-container /bin/bash

4. Working with Docker Volumes

4.1 Creating and Using Volumes

Volumes are used for persistent data storage, even if containers are removed.

1. Creating a volume:

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docker volume create my-data-volume

2. Using a volume:

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docker run -v my-data-volume:/data my-image

5. Networking in Docker

5.1 Creating and Managing Networks

1. Creating a custom network:

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docker network create my-custom-network

2. Running containers with custom networks:

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docker run --network my-custom-network my-image

6. Working with Docker Compose

Docker Compose is used to define and run multi-container Docker applications.

6.1 Basic Docker Compose Commands

1. Creating a Docker Compose file (docker-compose.yml):

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version: '3'
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services:
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  web:
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    image: nginx
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    ports:
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      - "80:80"

2. Starting Containers:

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docker-compose up

3. Stopping Containers:

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docker-compose down

7. Managing Images

7.1 Pulling Docker Images

To pull images from Docker Hub:

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docker pull <image-name>:<tag>

Example:

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docker pull nginx:latest

7.2 Pushing Docker Images

To push an image to a Docker registry:

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docker push <image-name>:<tag>

8. Securing and Managing Docker

1. Using Secrets:

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   docker secret create my-secret my-secret-file
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   docker service update --secret-add my-service my-secret
   

2. Security Practices:

   • Limit container privileges.

   • Use environment variables securely.

   • Limit access to Docker commands with user permissions.

9. Docker Compose with GitHub Actions

You can define Docker Compose workflows in GitHub Actions to automate building and deploying multi-container applications.

Example GitHub Actions Workflow:

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name: Build and Deploy
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on:
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  push:
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    branches:
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      - main
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jobs:
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  build:
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    runs-on: ubuntu-latest
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    services:
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      - name: my-web-service
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        image: nginx:latest
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    steps:
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      - name: Checkout Repository
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        uses: actions/checkout@v3
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      - name: Run Docker Compose
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        run: |
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          docker-compose up --build -d

Summary

By following these steps, you can effectively manage and utilize Docker containers for your development, testing, and deployment needs.