Day2: Docker images

What is a Docker image. Explain in 10 points.

1. Docker image is a repository.
2. 100s of base docker images are stored in hub.docker.com called registry.
3. Docker image consists of multiple filesystems -- ROOTFS + USERFS + ... //This both together are called base image
4. File systems are called layers as they are on top of each other in the docker images.
5. Each layer has a unique shad ID.
6. Docker image consists of multiple filesystems OR it is a collection of multiple filesystems.
7. Docker image has file system versioning.
8. For encrypting docker images, sha2-256bit algorithm is used.
9. All these layers merge to create one layer called mount.
10. Mount gets attached during runtime to the user.
11. If you change any file in a running container and stop it. The data will be stored at the diff directory. When the container will be restarted, then the file changes can be found intact.