OverlayFS
https://www.kernel.org/doc/html/latest/filesystems/overlayfs.html
https://zetawiki.com/wiki/OverlayFS
http://emal.iptime.org/noriwiki/index.php/Overlayfs
https://www.44bits.io/ko/post/how-docker-image-work
https://malwareanalysis.tistory.com/213
https://malwareanalysis.tistory.com/236
Overlay2
Refereneces
https://blog.naver.com/alice_k106/221530340759