How to Build, Tag, and Push Docker Images to Docker Hub

In this blog, we’ll walk through the process of building, tagging, and pushing a Docker image to Docker Hub. We will also troubleshoot some common errors encountered during this process.

• Lab 1: Building the Docker Image
• Lab 2: Tagging the Docker Image
• Lab 3: Pushing the Image to Docker Hub
• Troubleshooting Common Errors
• Conclusion

Lab 1: Building the Docker Image

Build the Image

In this first step, we are building the Docker image from a Dockerfile in the Electro project folder. The -t flag is used to tag the image with a version name.

Run the following command in your PowerShell or terminal:

Output:

Lab 2: Tagging the Docker Image

Now that the image is built, it’s time to tag it properly to push it to Docker Hub.

The image we built locally is electro:v1. We now need to tag it for our Docker Hub repository under the username theodora22. Here’s the command to tag the image:

Output:

You should not see any output after running this command, which means the image has been tagged successfully. You can verify the tagging by running:

Example Output:

Note Remember to create a repository first on docker hub before tagging the docker image.

Lab 3: Pushing the Image to Docker Hub

Now, let’s push the tagged image to Docker Hub.

Run the following command to push the image to your Docker Hub repository:

Expected Output:

Troubleshooting Common Errors

Error: Tag does not exist

This error occurs if the image isn’t tagged correctly or hasn’t been built yet. Ensure the image exists locally by checking with:

Then tag the image correctly:

And retry pushing.

Conclusion

In this lab, we learned how to:

1. Build a Docker image using a Dockerfile.
2. Tag the image appropriately to push it to Docker Hub.
3. Push the image to Docker Hub, making it available to others or for use in production.

Docker simplifies the process of building and deploying applications across various environments.