What are Docker image layers and why are they important?

What are Docker image layers and why are they important?

Docker image layers are the building blocks of Docker images. Each layer represents a set of file changes, and they are stacked on top of each other to form a complete image. Layers are important because they allow for efficient storage and sharing of images, as common layers can be reused across different images.

How do layers affect the size of a Docker image?

Layers can significantly affect the size of a Docker image. Each layer adds to the overall size, but because layers can be shared between images, using a common base image can help reduce redundancy and save space.

Can I see the layers of a Docker image?

Yes, you can view the layers of a Docker image using the command docker history <image_name>. This command shows you the size and creation date of each layer.

What happens if I change a file in a layer?

If you change a file in a layer, Docker creates a new layer on top of the existing one. This means the original layer remains unchanged, allowing for version control and easier rollbacks.