Added example of DockerHub deleting unused Docker images

I saw this link today in the news (to be implemented from November 1st,
2020), and because it is directly related to this work, I added it. Many
people assume that simply pushing a Docker image to DockerHub is enough to
preserve it, but ignore how much it costs to maintain the storage and
network capacity.

1 files changed, 3 insertions, 1 deletions

diff --git a/paper.tex b/paper.tex
index 80c8376..c1d7b34 100644
--- a/paper.tex
+++ b/paper.tex
@@ -143,7 +143,9 @@ Usually, images are imported with generic operating system (OS) names; e.g., \ci
 The extracted tarball (from \url{https://partner-images.canonical.com/core/xenial}) is updated almost monthly and only the most recent five are archived.
 Hence, if the Dockerfile is run in different months, its output image will contain different OS components.
 In the year 2024, when long-term support for this version of Ubuntu expires, the image will be unavailable at the expected URL.
-Other OSes have similar issues because pre-built binary files are large and expensive to maintain and archive.
+Generally, Pre-built binary files (like Docker images) are large and expensive to maintain and archive.
+%% This URL: https://www.docker.com/blog/scaling-dockers-business-to-serve-millions-more-developers-storage/}
+This prompted DockerHub (an online service to host Docker images, including many reproducible workflows) to delete images that have not been used for over 6 months.
 Furthermore, Docker requires root permissions, and only supports recent (``long-term-support'') versions of the host kernel, so older Docker images may not be executable.
 
 Once the host OS is ready, PMs are used to install the software or environment.