Docker Fundamentals : Hands On - I

Setting Up Docker on AWS EC2 (Ubuntu)

Step 1: Update the Package List

sudo apt-get update        

• Purpose: Updates the package list on your system to ensure you have the latest information about available software and updates.

sudo apt-get upgrade        

• Purpose: Upgrades all installed packages on your system to their latest versions based on the updated package list from the repositories. This ensures your software is up-to-date without adding or removing packages.

Step 2: Install Docker

sudo apt-get install docker.io        

• Downloads and installs the docker.io package, which contains the Docker Engine.
• Configures Docker to run as a service that starts automatically.

Step 3: Add User to Docker Group

sudo usermod -aG docker ubuntu && newgrp docker        

• Grants non-root users access to Docker commands by adding them to the docker group and activates the changes immediately.
• 𝐬𝐮𝐝𝐨 𝐮𝐬𝐞𝐫𝐦𝐨𝐝 -𝐚𝐆 𝐝𝐨𝐜𝐤𝐞𝐫 𝐮𝐛𝐮𝐧𝐭𝐮: Adds the user ubuntu to the docker group, allowing Docker commands to run without sudo.
• 𝐧𝐞𝐰𝐠𝐫𝐩 𝐝𝐨𝐜𝐤𝐞𝐫: Refreshes the user session to apply group changes without requiring a logout.

Step 4: Verifying the Installation

• Check the Docker version:

docker --version        

• Run a test container:

docker run hello-world        

Common Docker Commands

1. docker pull

• Purpose: Downloads a Docker image from a registry (e.g., Docker Hub).
• Syntax:

docker pull <image_name>        

2. docker images

• Purpose: Lists all images present locally.
• Syntax:

docker images        

3. docker ps

• Purpose: Lists all running containers.
• Syntax:

docker ps        

4. docker ps -a

• Purpose: Lists all containers, including stopped ones.
• Syntax:

docker ps -a        

5. docker run

• Purpose: Creates and starts a new container from an image.
• Syntax:

docker run <image_name>        

6. docker run -d

• Purpose: Runs a container in detached mode (in the background).
• Syntax:

docker run -d <image_name>        

Hands-On: Setting Up a MySQL Container with Docker

Step 1: Pull the MySQL Docker Image

docker pull mysql:latest        

• Purpose: Downloads the latest version of the official MySQL image from Docker Hub.
• What Happens: The command fetches the MySQL image and stores it locally on your system.

Verify the Download

docker images        

• Purpose: Lists all images downloaded to your system.
• What Happens: Displays the image name, tag, ID, and size.

Step 2: Run the MySQL Container

docker run -d -e MYSQL_ROOT_PASSWORD=password mysql:latest        

• Purpose: Creates and starts a MySQL container in detached mode.

Explanation of Options:

• -𝐝: Runs the container in detached mode (background).
• -𝐞 𝐌𝐘𝐒𝐐𝐋_𝐑𝐎𝐎𝐓_𝐏𝐀𝐒𝐒𝐖𝐎𝐑𝐃=𝐩𝐚𝐬𝐬𝐰𝐨𝐫𝐝: Sets the root password for MySQL inside the container.
• 𝐦𝐲𝐬𝐪𝐥:𝐥𝐚𝐭𝐞𝐬𝐭: Specifies the image and tag to use.

Verify the Container Is Running

docker ps        

• Purpose: Lists all currently running containers.
• What Happens: Displays container IDs, names, statuses, and ports.

Step 3: Access the Running Container

docker exec -it <container-id> bash        

• Purpose: Opens a terminal session inside the running container.

Explanation of Options:

• 𝐞𝐱𝐞𝐜: Executes a command inside a running container.
• -𝐢𝐭: Opens an interactive terminal session.
• <𝐜𝐨𝐧𝐭𝐚𝐢𝐧𝐞𝐫-𝐢𝐝>: Replace with the ID of your running container (from docker ps).

Access MySQL CLI Inside the Container

• After running the docker exec command, log into MySQL:

mysql -u root -p        

• Enter the root password (password).
• Test the connection by running:

show databases;        

Hands-On Guide: Setting Up NGINX with Docker

Step 1: Pull the NGINX Docker Image

• Run the following command to download the latest NGINX image:

docker pull nginx:latest        

• Verify that the image has been downloaded:

docker images        

Step 2: Run the NGINX Container

docker run -d -p 80:80 --name my-nginx nginx:latest        

Explanation:

• -𝐝: Runs the container in detached mode (in the background).
• -𝐩 80:80: Maps port 80 on the host to port 80 in the container.
• --𝐧𝐚𝐦𝐞 𝐦𝐲-𝐧𝐠𝐢𝐧𝐱: Assigns the name my-nginx to the container.
• 𝐧𝐠𝐢𝐧𝐱:𝐥𝐚𝐭𝐞𝐬𝐭: Specifies the image to use.

Confirm that the container is running:

docker ps        

Step 3: Access NGINX Using the EC2 Public IPv4 Address

• Open a browser and navigate to http://<Public_IPv4_Address>