First of all, thank you for taking the time to write this out. The feedback is very valuable. I will do my best to address each comment.

Let me start by laying out our design constraints. We knew we wanted a handful of simple features:

- minimal

- immutable

- and secure

and we approached them with the willingness to do whatever it took to achieve them, no matter how different it would be from any Linux distribution today.

The degree to which we want to obtain minimalism is what I like to call "ultra". Not a single file should be on the image that isn't absolutely needed. Furthermore, not a single process should be allowed to run that isn't required to obtain the goal of running Kubernetes. So we started by creating an image with just enough to run the kubelet and the kubelet only. Obviously, this isn't practical, but it was a place to start.

In implementing our immutability design constraint we decided to:

- make the root filesystem read-only - have no package manager - not allow any generic use of the OS (i.e. it would be only for the purposes of running Kubernetes)

When optimizing for one thing, you often degrade another. In our case, if we optimize for minimalism, then immutability becomes degraded. We need to address a way to manage and debug the node, and we need libraries/binaries to do so. With no package manager, this means everything must be baked into the image, and thus we degrade immutability.

Tacking on yet another design constraint, security, things become even more interesting. The more you add to a system, the higher the risk in vulnerabilities. The more allowed permissions in a system, the higher the risk in vulnerabilities. So minimalism, and immutability actually complement security. In our case, security has the highest priority of all, which means we aren't willing to degrade anything that supports the security of the system. So minimalism, and immutability must be present.

Aside from our design constraints of minimalism, and immutability, we also avoid C as much as possible. We want to build something using a modern language for all the reasons you would choose a modern language over C today, but mostly for security purposes.

Taking all the above into consideration, this meant that we are still left with figuring out how to manage a machine without degrading minimalism, immutability, and security. So without tooling on the rootfs, without a package manager, and without a way to run custom processes, we still need a way to obtain the information we need from a machine. Thus the API was born.

The API doesn't only solve the management issue, it also reenforces all of our design constraints:

- we can keep the image minimal with a single binary serving the API - we can keep the image immutable by building a robust API - we could retain security by using mutual TLS and offering a read-only API - we could write it in a modern language, using modern tooling (golang and gRPC)

At this point what need is there in SSH/console access if the design constraints essentially remove all usefulness in console access? The problem isn't necessarily the need for SSH/console, its the need for a way to get the data to make informed decisions.

There are also additional benefits to an API. There is a reason the concept exists. With an API you get a standarization, strong types, and constistent and well known output formats. The benefits are many.

I'd like to also point you in the direction of an execellent talk given this year at Blackhat: https://swagitda.com/speaking/us-19-Shortridge-Forsgren-Cont.... The section on D.I.E. in particular will add some additional support to the reasons I gave above.

That is my lengthy response to the reasoning behind the removal of SSH. Remember, just because we don't have SSH baked in, nothing ...