https://arkingc.github.io/2017/05/05/2017-05-05-docker-filesystem-overlay/
root@ubuntu:/var/lib/docker/overlay2# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d1544775a783 nginx "/docker-entrypoint.…" 6 hours ago Up 6 hours 80/tcp elastic_shockley root@ubuntu:/var/lib/docker/overlay2# df -h Filesystem Size Used Avail Use% Mounted on udev 126G 0 126G 0% /dev tmpfs 26G 1.7M 26G 1% /run /dev/sdc3 218G 14G 194G 7% / tmpfs 126G 0 126G 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 126G 0 126G 0% /sys/fs/cgroup /dev/sdc2 465M 81M 356M 19% /boot /dev/sdc1 243M 252K 243M 1% /boot/efi tmpfs 26G 0 26G 0% /run/user/1000 /dev/loop0 86M 86M 0 100% /snap/core/9994 /dev/loop1 45M 17M 25M 41% /tmp/my-rootfs overlay 218G 14G 194G 7% /var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5/merged none 218G 14G 194G 7% /home/ubuntu/dirC root@ubuntu:/var/lib/docker/overlay2#
root@ubuntu:/home/ubuntu# tree -L 2 /var/lib/docker/overlay2/ /var/lib/docker/overlay2/ ├── 0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df │ ├── diff │ ├── link │ ├── lower │ └── work ├── 0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df-init │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 164f8b5ab975c5eceb93e5c9fdd4b38bbea82b9be02c174744803bddea4a11aa │ ├── committed │ ├── diff │ └── link ├── 3788a1d89b1bc944ba327ca0324eb9443031789e763601ee9750fa7d95437abd │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 5b5ae62b54531106bccfad465de30780c4f133693c74b804d87c3c2546541108 │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 6510d1f15249d407e43e6fa1246679929c8ddad57da56dc10b83f4cbaa17c705 │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 71d1c02e60dfef29316cba9191b04c367381028e0518080f808b25087919ac41 │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 7476c0bf71a728df117c608552402720681f87a8d4229d3e6550a3b00124df2e │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── 7ba2254bf85fb157f24f026a04150bf5aa6b4d772454f5c6511a8993055e1c2e │ ├── committed │ ├── diff │ └── link ├── 8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5 │ ├── diff │ ├── link │ ├── lower │ ├── merged │ └── work ├── 8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5-init │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work ├── a09755a54062a2fb04311aa8630e9b97ce51209411c858165b5f681d562c5e9c │ ├── committed │ ├── diff │ └── link ├── c38cdc062d10e73519af50b85880eee7848a5eee8c196a3e01378befa427b875 │ ├── committed │ ├── diff │ ├── link │ ├── lower │ └── work └── l ├── DV6GEXARCBVAEZUJFL6KW3HSBJ -> ../71d1c02e60dfef29316cba9191b04c367381028e0518080f808b25087919ac41/diff ├── GBVTARSEMDEDMBRBE7CECORBH6 -> ../0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df/diff ├── I2CALNKEYKBOZMIZ67WXTUJ43D -> ../0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df-init/diff ├── II4VJVPYFTMMWUOKJCACYPZB5E -> ../8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5/diff ├── MN4IC4KQI4FAGG4ZIPEYHSPJGW -> ../5b5ae62b54531106bccfad465de30780c4f133693c74b804d87c3c2546541108/diff ├── NG4DKVMB5QH6XHGH23GOVNGUBB -> ../8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5-init/diff ├── OHD7XJ4JW7PEYZRGBIBJZYTLYY -> ../6510d1f15249d407e43e6fa1246679929c8ddad57da56dc10b83f4cbaa17c705/diff ├── P2FHY5TVXEA2IYWG37CHNM3MTE -> ../a09755a54062a2fb04311aa8630e9b97ce51209411c858165b5f681d562c5e9c/diff ├── PWRZKLZFFPTNF76EUWJQWMXDXN -> ../3788a1d89b1bc944ba327ca0324eb9443031789e763601ee9750fa7d95437abd/diff ├── QYAY6NY35IL5RIM4PE5ZLY7C44 -> ../7476c0bf71a728df117c608552402720681f87a8d4229d3e6550a3b00124df2e/diff ├── R6NXNIP3FZ7H4ZJ5V3BSSUET3Y -> ../c38cdc062d10e73519af50b85880eee7848a5eee8c196a3e01378befa427b875/diff ├── SASKARTZ26LG5BYUKMI5WXE6MR -> ../164f8b5ab975c5eceb93e5c9fdd4b38bbea82b9be02c174744803bddea4a11aa/diff └── XKGKOR5GBTIGTO6EHG22MIZ7NE -> ../7ba2254bf85fb157f24f026a04150bf5aa6b4d772454f5c6511a8993055e1c2e/diff 51 directories, 34 files root@ubuntu:/home/ubuntu#
root@ubuntu:/var/lib/docker/overlay2# du -sh * 24K 0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df 48K 0c8fd8ebc4beeb02f1efb2ce0891c60bdc3ab39a557a3f28e8bdf4760156e5df-init 72M 164f8b5ab975c5eceb93e5c9fdd4b38bbea82b9be02c174744803bddea4a11aa 24K 3788a1d89b1bc944ba327ca0324eb9443031789e763601ee9750fa7d95437abd 28K 5b5ae62b54531106bccfad465de30780c4f133693c74b804d87c3c2546541108 64M 6510d1f15249d407e43e6fa1246679929c8ddad57da56dc10b83f4cbaa17c705 32K 71d1c02e60dfef29316cba9191b04c367381028e0518080f808b25087919ac41 28K 7476c0bf71a728df117c608552402720681f87a8d4229d3e6550a3b00124df2e 70M 7ba2254bf85fb157f24f026a04150bf5aa6b4d772454f5c6511a8993055e1c2e 132M 8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5 40K 8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5-init 1.5M a09755a54062a2fb04311aa8630e9b97ce51209411c858165b5f681d562c5e9c 96K c38cdc062d10e73519af50b85880eee7848a5eee8c196a3e01378befa427b875 56K l root@ubuntu:/var/lib/docker/overlay2# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d1544775a783 nginx "/docker-entrypoint.…" 7 hours ago Up 7 hours 80/tcp elastic_shockley 83c519864c4b busybox "sh" 2 days ago Created naughty_darwin root@ubuntu:/var/lib/docker/overlay2# docker inspect d1544775a783 | grep overlay2 "Driver": "overlay2", "LowerDir": "/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5-init/diff:/var/lib/docker/overlay2/7476c0bf71a728df117c608552402720681f87a8d4229d3e6550a3b00124df2e/diff:/var/lib/docker/overlay2/5b5ae62b54531106bccfad465de30780c4f133693c74b804d87c3c2546541108/diff:/var/lib/docker/overlay2/3788a1d89b1bc944ba327ca0324eb9443031789e763601ee9750fa7d95437abd/diff:/var/lib/docker/overlay2/6510d1f15249d407e43e6fa1246679929c8ddad57da56dc10b83f4cbaa17c705/diff:/var/lib/docker/overlay2/7ba2254bf85fb157f24f026a04150bf5aa6b4d772454f5c6511a8993055e1c2e/diff", "MergedDir": "/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5/merged", "UpperDir": "/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5/diff", "WorkDir": "/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5/work" "Name": "overlay2" root@ubuntu:/var/lib/docker/overlay2#
root@ubuntu:/var/lib/docker/overlay2# ls 8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5 diff link lower merged work root@ubuntu:/var/lib/docker/overlay2#
root@ubuntu:/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5# find ./ -name nginx ./diff/etc/nginx ./diff/var/cache/nginx ./merged/usr/sbin/nginx ./merged/usr/lib/nginx ./merged/usr/share/doc/nginx ./merged/usr/share/nginx ./merged/etc/logrotate.d/nginx ./merged/etc/default/nginx ./merged/etc/init.d/nginx ./merged/etc/nginx ./merged/var/cache/nginx ./merged/var/log/nginx root@ubuntu:/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5#
f4db0a37d5# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d1544775a783 nginx "/docker-entrypoint.…" 7 hours ago Up 7 hours 80/tcp elastic_shockley root@ubuntu:/var/lib/docker/overlay2/8534450bbe83e64ff72f91ead54c343eddd227751e07ddc06e260df4db0a37d5# docker exec -it d1544775a783 bash root@d1544775a783:/# find ./ -name nginx ./usr/sbin/nginx ./usr/lib/nginx ./usr/share/doc/nginx ./usr/share/nginx find: './proc/49/map_files': Permission denied ./etc/logrotate.d/nginx ./etc/default/nginx ./etc/init.d/nginx ./etc/nginx ./var/cache/nginx ./var/log/nginx root@d1544775a783:/#
root@ubuntu:/run/kata-containers# find ./ -name nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/sbin/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/lib/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/share/doc/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/share/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/logrotate.d/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/default/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/init.d/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/var/cache/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/mounts/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/var/log/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/sbin/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/lib/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/share/doc/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/usr/share/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/logrotate.d/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/default/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/init.d/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/etc/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/var/cache/nginx ./shared/sandboxes/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/shared/d1544775a783247ec3576a4756c6f3ab01bd157a2af12e5532b2854b8a202465/rootfs/var/log/nginx root@ubuntu:/run/kata-containers#