Docker Image

1) It's the layers of file system>
2) All the layers have relationship with each other if you are pulling the top layer the parent layer will be pulled automatically
3) The Layer id will be stored under storage area example /var/lib/docker/overlay2
4) The data layer and file system will be under overlay2
5) the meta data like environment variable will be under images folder
6) When we start a container there is a merge layer will get created, which is the combination of all the layers which we have pulled
7) Even Many images are pulled the layer id will be stored only under overlay2 folder
8) This Images are using sha 256 algorithm.
9) When we add some data into the container and even we stopped the container after that, the data will be available under overlay2 folder as a layer, and it will get attached to the container once is started.
10) We can see the layer information using "df -kh" and also the memory using "du -h --max-dept=1"