[sclevine]

Dockerfiles require you to rebuild lower layers when any upper layers change, even though the OCI image format doesn't care about this. Cloud Native Buildpacks can intelligently choose which layers to rebuild and replace. Additionally, certain layers can be updated en mass for many images on a registry (using cross-repo blob mounting, with no real data transfer!), which is useful for patching CVEs quickly at scale.

The samples take advantage of this (as well as a separate transparent cache) in order to demonstrate the different aspects of the formal spec. A simple buildpack is not necessarily much more complicated than a simple Dockerfile.

[gigatexal]

Yes, if the underlying layer’s hash changes then it has to be rebuilt. But if you just change index.html it caches the other layers and builds are very quick.

My issue with Buildpacks is that it looks like a glorified bash script (which is a skill I am not bashing — pun not intended) whereas a dockerfile is much more human readable and the idea of layers, for a guy coming from a systems background, is much more intuitive for me. The analogy of a very lightweight VM makes perfect sense to me which means I’m much more productive with it.