What is a Docker image?
To simply understand, the Docker image is a Linux file system (Root FileSystem). This file system contains programs that can run in the Linux kernel and corresponding data.
Two characteristics of the image:
1. The image is layered
That is, an image can be composed of multiple intermediate layers. Multiple images can share the same middle layer, and we can also generate a new image by adding one more layer to the image.
2. The image is read-only
After the image is built, it cannot be modified. As we said above, adding a layer to build a new image, In the process, a temporary container is actually created, and files are added or deleted on the container to form a new image, because the container can be changed dynamically.
Recommended tutorial: docker tutorial
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