What is a Docker image. Explain in 10 points.
- Docker image consists multiple file system.
- It is a name inside repository and this name will be linked to docker Layer ID.
- This Layer Id is used to recognize the parents for that layer and so on.
- Docker images will have multiple layers. The rootfile System or base image at the bottom layer and then there will be multiple layers on top it for software and applications.
- When a docker image is pulled these data layers will stored in docker locally (inside overlay2 - again depends on the filesystem type), and meta layers will be there in images directory.
- When we create a container using this image all layers will be merged and mounted to the user attached with container.
- If are creating any new file in container, it will be stored at two places diff and merge.
- mount for an image is conmbination of diff and image layers.
- when you stop a container the merge directory go away.