Some workloads want an image each. A build that needs a specific toolchain, a test that needs a specific database client, a task whose dependencies are described by something other than a human. The instinct is a Dockerfile and a builder. That means a daemon or a rootless equivalent, a build job in the path of every request, a registry filling with near-identical layers, and, the part that turned out to matter, an arbitrary program running at build time on input you did not write. There is...