That's probably because they are practically most used for the underlying OS of a Kubernetes host (seeing as how it is difficult by definition to configure an immutable install).

If you really think about it, what's the difference between spinning up a VM with a preconfigured image and spinning up a VM with an _immutable_ preconfigured image?

The difference is that one is immutable and the other is not. One can be rolled back to earlier version while retaining user data and the other doesn't offer that ability.

Sure, but the GKE autoscaler will happily erase and recreate machines whenever it wants.

Divergences from the base image are inherently limited because of that.

Despite the name, that's not what immutable distros are for. GKE won't let yet restore previous generation of configured and component versioned base image.

Plus 1 on this - I've probably had direct responsibility for managing fleets of roughly 50,000 linux hosts - never seen an immutable distro. We usually just burn a fresh image of whatever mainline ubuntu is offering every week or two into the fleet. Saying that containers are becoming a defacto standard is reasonable though - pretty much every company I've worked with and my coworkers have worked with have shifted everything into containers (at least in companies with x00k microservice instances running on ~100k machine environments).

>I've probably had direct responsibility for managing fleets of roughly 50,000 linux hosts - never seen an immutable distro.

plus, given your wealth of experience, I'm more interested in what linux you run on your personal laptop

WSL2 + Ubuntu. It's either MacOS or Windows in BigCorp with all the Okta/Crowdstrike/... stuff they require - and I like the apt-get convenience.

Most of my time is in Tmux anyways. Over the last 15 years the client side has been one of MacOS, ArchLinux, Ubuntu, and now Windows/WSL2.

The real activity has shifted up to the orchestration and service discovery layers - nomad, k8s, consul, and whatever fleetmanagement/cluster management layers maintains the hosts (a lot of homebuilt + terraform + chef/argo-workflow in our world). It's been years since I was really that concerned about the linux host side of things - why care about "immutable" when the entire machine/image is ephemeral for < 1 week (or in some cases, <1 day) anyways?