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Push & Pull

To work with Docker images, you primarily use the docker push and docker pull commands to move images between your local machine and a container registry (like Docker Hub).

Docker Push and Pull

1. Docker Pull (Downloading Images)​

The docker pull command is used to download an image from a registry to your local machine.

  • Basic Syntax: 
    docker pull <image_name>:<tag>
  • What happens: Docker contacts the registry, downloads the image layers, and stores them in your local image cache. If you already have the image locally, Docker will skip the download.

2. Docker Push (Uploading Images)​

The docker push command is used to upload your local images to a registry so they can be shared or used in other environments.

  • Prerequisite: You must be logged in to the registry (e.g., docker login).
  • Basic Syntax: 
    docker push <registry_url>/<username>/<image_name>:<tag>
  • Steps to Push:
    1. Build your image: Tag it with your registry username. docker build -t your-username/my-app:latest .
    2. Push the image: docker push your-username/my-app:latest
  • What happens: Docker calculates which layers have changed and only uploads the necessary layers to the registry, making the process efficient.