Difference between pulling and building an image.

In Docker, pulling an image means downloading an existing image from a registry, such as Docker Hub, to your local system. On the other hand, building an image means creating a new Docker image using a Dockerfile and the source code of your application.

Here are some key differences between pulling and building an image in Docker:

Source of the image: When you pull an image, you're downloading an existing image from a registry, such as Docker Hub. When you build an image, you're creating a new image using a Dockerfile and the source code of your application.

Time required: Pulling an image is usually faster than building an image, as the image is already built and ready to use. Building an image can take longer, especially if your application has a large number of dependencies or requires complex configurations.

Customization: When you pull an image, you're using a pre-built image that may not be customized to your specific needs. When you build an image, you can customize it to include the specific dependencies and configurations required by your application.

Dependency management: When you pull an image, you're relying on the image's creator to manage the dependencies and configurations. When you build an image, you have control over the dependencies and configurations, and can ensure that they're up-to-date and secure.

Portability: When you pull an image, you're using an existing image that can be run on any system that supports Docker. When you build an image, the image is specific to your local system and may not be portable to other systems without modification.

In summary, pulling an image is a quick and easy way to use an existing Docker image, while building an image provides more control and customization over the dependencies and configurations of your application.