OverlayFS Layered Storage Driver Lab
Interactive simulation of lowerdir image layers, upperdir container layers, and Copy-on-Write (CoW).
Storage Driver Architecture
OverlayFS Union Filesystem & Copy-on-Write (CoW)
Container Read-Write Layer (upperdir)Ephemeral (Deleted with container)
Empty (No files written yet)
Image Layer #3 (lowerdir) [sha256:4f8e...]Read-Only Immutable
COPY . /app ➔ /app/app.js (Original code)Image Layer #2 (lowerdir) [sha256:91bc...]Read-Only Immutable
RUN apk add nodejs ➔ /usr/bin/node (Node runtime binaries)Base Image Layer #1 (lowerdir) [sha256:3a11...]Read-Only Immutable
FROM alpine:latest ➔ /bin/sh, /etc/os-release, /lib/ld-musl.soStorage Engine Log:
OverlayFS mounted. All 3 image layers in lowerdir are read-only and immutable.