Lab 20: Push Docker Image to Docker Hub¶

Objective

By the end of this lab, you will be able to:

Tag and push a Docker image to Docker Hub
Verify the image on your Docker Hub profile

Prerequisites

Docker installed and image built (Lab 19)
Docker Hub account

Docker Hub Account Creation¶

In your desktop go to following address:

https://hub.docker.com/
Click on Sign Up
Select Personal Tab
Enter your email address
Put your desired Username
Enter your password
Click on Sign Up

docker login -u <your_username>

Enter your Docker Hub username and password when prompted.

Step 2: Tag Your Docker Image¶

Replace <your_dockerhub_username> with your actual Docker Hub username:

docker tag flask-demo-app <your_dockerhub_username>/flask-demo-app:v1

Example:

docker tag flask-demo-app sidtrainings/flask-demo-app:v1

What are Docker Tags? Docker tags are used to assign a unique identifier to a Docker image, allowing you to manage and organize different versions of your images. Tags are essentially aliases for image IDs and can be used to specify versions, variants, or other distinguishing characteristics of an image.

Tagging an Image To tag an image in Docker, you can use the docker tag command. This command creates a new tag for an existing image, allowing you to reference the image by the new tag. The general syntax for the docker tag command is:
docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]

Step 3: Push the Image to Docker Hub¶

docker push <your_dockerhub_username>/flask-demo-app:v1

Step 4: Verify on Docker Hub¶

Go to https://hub.docker.com
Login to your account
Navigate to Repositories and confirm your image flask-demo-app:v1 is listed

(OPTIONAL) Step 5: Pull and Run the Image from Docker Hub¶

Now that your image is on Docker Hub, you (or anyone) can use it anywhere Docker is installed.

🔽 To pull the image:

docker pull your-dockerhub-username/flask-demo-app:v1

Replace your-dockerhub-username with your actual Docker Hub username.

▶️ To run the container:

docker run -d -p 8081:5000 your-dockerhub-username/flask-demo-app:v1

Now, visit http://localhost:8081 (or VM-IP:8081 if running on a remote machine) to see your Flask app in action!

🚀 What’s Next?¶

In Lab 21, you will write a Jenkins pipeline to automate image build and deployment.