Building and Inspecting Docker Images to Verify Layer Sharing

5th chunk of `content/manuals/engine/storage/drivers/_index.md`

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   => => naming to docker.io/acme/my-base-image:1.0                                              0.0s
   ```

6. Build the second image.

   ```console
   $ docker build -t acme/my-final-image:1.0 -f Dockerfile .

   [+] Building 3.6s (12/12) FINISHED
   => [internal] load build definition from Dockerfile                                            0.1s
   => => transferring dockerfile: 156B                                                            0.0s
   => [internal] load .dockerignore                                                               0.1s
   => => transferring context: 2B                                                                 0.0s
   => resolve image config for docker.io/docker/dockerfile:1                                      0.5s
   => CACHED docker-image://docker.io/docker/dockerfile:1@sha256:9e2c9eca7367393aecc68795c671...  0.0s
   => [internal] load .dockerignore                                                               0.0s
   => [internal] load build definition from Dockerfile                                            0.0s
   => [internal] load metadata for docker.io/acme/my-base-image:1.0                               0.0s
   => [internal] load build context                                                               0.2s
   => => transferring context: 340B                                                               0.0s
   => [1/3] FROM docker.io/acme/my-base-image:1.0                                                 0.2s
   => [2/3] COPY . /app                                                                           0.1s
   => [3/3] RUN chmod +x /app/hello.sh                                                            0.4s
   => exporting to image                                                                          0.1s
   => => exporting layers                                                                         0.1s
   => => writing image sha256:8bd85c42fa7ff6b33902ada7dcefaaae112bf5673873a089d73583b0074313dd    0.0s
   => => naming to docker.io/acme/my-final-image:1.0                                              0.0s
   ```

7. Check out the sizes of the images.

   ```console
   $ docker image ls

   REPOSITORY             TAG     IMAGE ID         CREATED               SIZE
   acme/my-final-image    1.0     8bd85c42fa7f     About a minute ago    7.75MB
   acme/my-base-image     1.0     da3cf8df55ee     2 minutes ago         7.75MB
   ```

8. Check out the history of each image.

   ```console
   $ docker image history acme/my-base-image:1.0

   IMAGE          CREATED         CREATED BY                                      SIZE      COMMENT
   da3cf8df55ee   5 minutes ago   RUN /bin/sh -c apk add --no-cache bash # bui…   2.15MB    buildkit.dockerfile.v0
   <missing>      7 weeks ago     /bin/sh -c #(nop)  CMD ["/bin/sh"]              0B
   <missing>      7 weeks ago     /bin/sh -c #(nop) ADD file:f278386b0cef68136…   5.6MB
   ```

   Some steps don't have a size (`0B`), and are metadata-only changes, which do
   not produce an image layer and don't take up any size, other than the metadata
   itself. The output above shows that this image consists of 2 image layers.

   ```console
   $ docker image history  acme/my-final-image:1.0

   IMAGE          CREATED         CREATED BY                                      SIZE      COMMENT
   8bd85c42fa7f   3 minutes ago   CMD ["/bin/sh" "-c" "/app/hello.sh"]            0B        buildkit.dockerfile.v0
   <missing>      3 minutes ago   RUN /bin/sh -c chmod +x /app/hello.sh # buil…   39B       buildkit.dockerfile.v0
   <missing>      3 minutes ago   COPY . /app # buildkit                          222B      buildkit.dockerfile.v0
   <missing>      4 minutes ago   RUN /bin/sh -c apk add --no-cache bash # bui…   2.15MB    buildkit.dockerfile.v0
   <missing>      7 weeks ago     /bin/sh -c #(nop)  CMD ["/bin/sh"]              0B
   <missing>      7 weeks ago     /bin/sh -c #(nop) ADD file:f278386b0cef68136…   5.6MB
   ```

   Notice that all steps of the first image are also included in the final

Title: Building and Inspecting Docker Images to Verify Layer Sharing

Summary

This section details the process of building two Docker images and inspecting their sizes and histories to confirm that they share common layers. It provides commands to build the 'acme/my-base-image:1.0' and 'acme/my-final-image:1.0' images, followed by instructions to use 'docker image ls' to view their sizes and 'docker image history' to examine the layers each image comprises. The example highlights how the final image reuses layers from the base image, demonstrating Docker's layer caching mechanism.